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"),t("span",{pre:!0,attrs:{class:"token class-name"}},[s._v("System")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(".")]),s._v("out"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(".")]),t("span",{pre:!0,attrs:{class:"token function"}},[s._v("println")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("(")]),s._v("list"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(".")]),t("span",{pre:!0,attrs:{class:"token function"}},[s._v("stream")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("(")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(")")]),s._v("\n                "),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(".")]),t("span",{pre:!0,attrs:{class:"token function"}},[s._v("noneMatch")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("(")]),s._v("name "),t("span",{pre:!0,attrs:{class:"token operator"}},[s._v("->")]),s._v(" name"),t("span",{pre:!0,attrs:{class:"token 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punctuation"}},[s._v("@Test")]),s._v("\n    "),t("span",{pre:!0,attrs:{class:"token keyword"}},[s._v("public")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token keyword"}},[s._v("void")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token function"}},[s._v("find")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("(")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(")")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("{")]),s._v("\n        "),t("span",{pre:!0,attrs:{class:"token comment"}},[s._v("// 都是获取第一个元素")]),s._v("\n        "),t("span",{pre:!0,attrs:{class:"token class-name"}},[s._v("Optional")]),t("span",{pre:!0,attrs:{class:"token generics"}},[t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("<")]),t("span",{pre:!0,attrs:{class:"token class-name"}},[s._v("String")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(">")])]),s._v(" optional "),t("span",{pre:!0,attrs:{class:"token operator"}},[s._v("=")]),s._v(" 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"),t("span",{pre:!0,attrs:{class:"token class-name"}},[s._v("System")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(".")]),s._v("out"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(".")]),t("span",{pre:!0,attrs:{class:"token function"}},[s._v("println")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("(")]),s._v("maxAge"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(".")]),t("span",{pre:!0,attrs:{class:"token function"}},[s._v("get")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("(")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(")")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(")")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(";")]),s._v("\n    \n        "),t("span",{pre:!0,attrs:{class:"token comment"}},[s._v("// 获取年龄总和")]),s._v("\n        "),t("span",{pre:!0,attrs:{class:"token class-name"}},[s._v("Optional")]),t("span",{pre:!0,attrs:{class:"token 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       "),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(".")]),t("span",{pre:!0,attrs:{class:"token function"}},[s._v("reduce")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("(")]),t("span",{pre:!0,attrs:{class:"token class-name"}},[s._v("Integer")]),t("span",{pre:!0,attrs:{class:"token operator"}},[s._v("::")]),t("span",{pre:!0,attrs:{class:"token function"}},[s._v("sum")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(")")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(";")]),s._v("\n        "),t("span",{pre:!0,attrs:{class:"token class-name"}},[s._v("System")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(".")]),s._v("out"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(".")]),t("span",{pre:!0,attrs:{class:"token function"}},[s._v("println")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("(")]),s._v("totalAge"),t("span",{pre:!0,attrs:{class:"token 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"),t("div",{staticClass:"line-numbers-wrapper"},[t("span",{staticClass:"line-number"},[s._v("1")]),t("br"),t("span",{staticClass:"line-number"},[s._v("2")]),t("br"),t("span",{staticClass:"line-number"},[s._v("3")]),t("br"),t("span",{staticClass:"line-number"},[s._v("4")]),t("br"),t("span",{staticClass:"line-number"},[s._v("5")]),t("br"),t("span",{staticClass:"line-number"},[s._v("6")]),t("br"),t("span",{staticClass:"line-number"},[s._v("7")]),t("br"),t("span",{staticClass:"line-number"},[s._v("8")]),t("br"),t("span",{staticClass:"line-number"},[s._v("9")]),t("br"),t("span",{staticClass:"line-number"},[s._v("10")]),t("br"),t("span",{staticClass:"line-number"},[s._v("11")]),t("br"),t("span",{staticClass:"line-number"},[s._v("12")]),t("br"),t("span",{staticClass:"line-number"},[s._v("13")]),t("br"),t("span",{staticClass:"line-number"},[s._v("14")]),t("br"),t("span",{staticClass:"line-number"},[s._v("15")]),t("br"),t("span",{staticClass:"line-number"},[s._v("16")]),t("br"),t("span",{staticClass:"line-number"},[s._v("17")]),t("br"),t("span",{staticClass:"line-number"},[s._v("18")]),t("br"),t("span",{staticClass:"line-number"},[s._v("19")]),t("br"),t("span",{staticClass:"line-number"},[s._v("20")]),t("br"),t("span",{staticClass:"line-number"},[s._v("21")]),t("br"),t("span",{staticClass:"line-number"},[s._v("22")]),t("br"),t("span",{staticClass:"line-number"},[s._v("23")]),t("br"),t("span",{staticClass:"line-number"},[s._v("24")]),t("br"),t("span",{staticClass:"line-number"},[s._v("25")]),t("br"),t("span",{staticClass:"line-number"},[s._v("26")]),t("br")])]),t("h4",{attrs:{id:"maptoint"}},[t("a",{staticClass:"header-anchor",attrs:{href:"#maptoint"}},[s._v("#")]),s._v(" 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"),t("span",{pre:!0,attrs:{class:"token comment"}},[s._v("// 将Integer类型转换为int类型, 可以节省空间")]),s._v("\n        "),t("span",{pre:!0,attrs:{class:"token class-name"}},[s._v("IntStream")]),s._v(" intStream "),t("span",{pre:!0,attrs:{class:"token operator"}},[s._v("=")]),s._v(" stream\n                "),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(".")]),t("span",{pre:!0,attrs:{class:"token function"}},[s._v("mapToInt")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("(")]),t("span",{pre:!0,attrs:{class:"token class-name"}},[s._v("Integer")]),t("span",{pre:!0,attrs:{class:"token operator"}},[s._v("::")]),t("span",{pre:!0,attrs:{class:"token function"}},[s._v("intValue")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(")")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(";")]),s._v("\n    "),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("}")]),s._v("\n"),t("span",{pre:!0,attrs:{class:"token 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方法是不同的")])])])]),s._v(" "),t("div",{staticClass:"language-text line-numbers-mode"},[t("pre",{pre:!0,attrs:{class:"language-text"}},[t("code",[s._v("static &lt;T> Stream&lt;T> concat(Stream&lt;? extends T> a, Stream&lt;? extends T> b){...}\n")])]),s._v(" "),t("div",{staticClass:"line-numbers-wrapper"},[t("span",{staticClass:"line-number"},[s._v("1")]),t("br")])]),t("ul",[t("li",[s._v("基本使用")])]),s._v(" "),t("div",{staticClass:"language-java line-numbers-mode"},[t("pre",{pre:!0,attrs:{class:"language-java"}},[t("code",[t("span",{pre:!0,attrs:{class:"token keyword"}},[s._v("public")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token keyword"}},[s._v("class")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token class-name"}},[s._v("StreamTest")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("{")]),s._v("\n    "),t("span",{pre:!0,attrs:{class:"token annotation punctuation"}},[s._v("@Test")]),s._v("\n    "),t("span",{pre:!0,attrs:{class:"token keyword"}},[s._v("public")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token keyword"}},[s._v("void")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token function"}},[s._v("concat")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("(")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(")")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("{")]),s._v("\n        "),t("span",{pre:!0,attrs:{class:"token class-name"}},[s._v("Stream")]),t("span",{pre:!0,attrs:{class:"token generics"}},[t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("<")]),t("span",{pre:!0,attrs:{class:"token class-name"}},[s._v("String")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(">")])]),s._v(" streamA "),t("span",{pre:!0,attrs:{class:"token operator"}},[s._v("=")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token class-name"}},[s._v("Stream")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(".")]),t("span",{pre:!0,attrs:{class:"token function"}},[s._v("of")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("(")]),t("span",{pre:!0,attrs:{class:"token string"}},[s._v('"张三"')]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(")")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(";")]),s._v("\n        "),t("span",{pre:!0,attrs:{class:"token class-name"}},[s._v("Stream")]),t("span",{pre:!0,attrs:{class:"token generics"}},[t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("<")]),t("span",{pre:!0,attrs:{class:"token class-name"}},[s._v("String")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(">")])]),s._v(" streamB "),t("span",{pre:!0,attrs:{class:"token operator"}},[s._v("=")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token class-name"}},[s._v("Stream")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(".")]),t("span",{pre:!0,attrs:{class:"token function"}},[s._v("of")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("(")]),t("span",{pre:!0,attrs:{class:"token string"}},[s._v('"李四"')]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(")")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(";")]),s._v("\n        "),t("span",{pre:!0,attrs:{class:"token comment"}},[s._v("// 将以上流合并, 合并的流就不能够继续操作了")]),s._v("\n        "),t("span",{pre:!0,attrs:{class:"token class-name"}},[s._v("Stream")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(".")]),t("span",{pre:!0,attrs:{class:"token function"}},[s._v("concat")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("(")]),s._v("streamA"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(",")]),s._v(" streamB"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(")")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(".")]),t("span",{pre:!0,attrs:{class:"token function"}},[s._v("forEach")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("(")]),t("span",{pre:!0,attrs:{class:"token class-name"}},[s._v("System")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(".")]),s._v("out"),t("span",{pre:!0,attrs:{class:"token operator"}},[s._v("::")]),t("span",{pre:!0,attrs:{class:"token function"}},[s._v("println")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(")")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(";")]),s._v("\n    "),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("}")]),s._v("\n"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("}")]),s._v("\n")])]),s._v(" "),t("div",{staticClass:"line-numbers-wrapper"},[t("span",{staticClass:"line-number"},[s._v("1")]),t("br"),t("span",{staticClass:"line-number"},[s._v("2")]),t("br"),t("span",{staticClass:"line-number"},[s._v("3")]),t("br"),t("span",{staticClass:"line-number"},[s._v("4")]),t("br"),t("span",{staticClass:"line-number"},[s._v("5")]),t("br"),t("span",{staticClass:"line-number"},[s._v("6")]),t("br"),t("span",{staticClass:"line-number"},[s._v("7")]),t("br"),t("span",{staticClass:"line-number"},[s._v("8")]),t("br"),t("span",{staticClass:"line-number"},[s._v("9")]),t("br")])]),t("h3",{attrs:{id:"_1-5-stream综合案例"}},[t("a",{staticClass:"header-anchor",attrs:{href:"#_1-5-stream综合案例"}},[s._v("#")]),s._v(" 1.5 Stream综合案例")]),s._v(" "),t("ul",[t("li",[s._v("现在有两个 ArrayList 集合存储队伍当中的多个成员姓名，要求使用Stream实现若干操作步骤：\n"),t("ol",[t("li",[s._v("第一个队伍只要名字为3个字的成员姓名；")]),s._v(" "),t("li",[s._v("第一个队伍筛选之后只要前3个人；")]),s._v(" "),t("li",[s._v("第二个队伍只要姓张的成员姓名；")]),s._v(" "),t("li",[s._v("第二个队伍筛选之后不要前2个人；")]),s._v(" "),t("li",[s._v("将两个队伍合并为一个队伍；")]),s._v(" "),t("li",[s._v("根据姓名创建 Person 对象；")]),s._v(" "),t("li",[s._v("打印整个队伍的Person对象信息。")])])])]),s._v(" "),t("div",{staticClass:"language-java line-numbers-mode"},[t("pre",{pre:!0,attrs:{class:"language-java"}},[t("code",[t("span",{pre:!0,attrs:{class:"token keyword"}},[s._v("public")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token keyword"}},[s._v("class")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token class-name"}},[s._v("StreamCaseDemo")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("{")]),s._v("\n    "),t("span",{pre:!0,attrs:{class:"token keyword"}},[s._v("public")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token keyword"}},[s._v("static")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token keyword"}},[s._v("void")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token function"}},[s._v("main")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("(")]),t("span",{pre:!0,attrs:{class:"token class-name"}},[s._v("String")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("[")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("]")]),s._v(" args"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(")")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("{")]),s._v("\n        "),t("span",{pre:!0,attrs:{class:"token class-name"}},[s._v("List")]),t("span",{pre:!0,attrs:{class:"token generics"}},[t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("<")]),t("span",{pre:!0,attrs:{class:"token class-name"}},[s._v("String")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(">")])]),s._v(" one "),t("span",{pre:!0,attrs:{class:"token operator"}},[s._v("=")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token keyword"}},[s._v("new")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token class-name"}},[s._v("ArrayList")]),t("span",{pre:!0,attrs:{class:"token generics"}},[t("span",{pre:!0,attrs:{class:"token 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string"}},[s._v('"苏星河"')]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(",")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token string"}},[s._v('"老子"')]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(",")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token string"}},[s._v('"庄子"')]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(",")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token string"}},[s._v('"孙子"')]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(",")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token string"}},[s._v('"洪七公"')]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(")")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(";")]),s._v("\n        "),t("span",{pre:!0,attrs:{class:"token class-name"}},[s._v("Collections")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(".")]),t("span",{pre:!0,attrs:{class:"token function"}},[s._v("addAll")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("(")]),s._v("two"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(",")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token string"}},[s._v('"古力娜扎"')]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(",")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token string"}},[s._v('"张无忌"')]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(",")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token string"}},[s._v('"张三丰"')]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(",")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token string"}},[s._v('"赵丽颖"')]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(",")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token string"}},[s._v('"张二狗"')]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(",")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token string"}},[s._v('"张天爱"')]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(",")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token string"}},[s._v('"张三"')]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(")")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(";")]),s._v("\n    \n        "),t("span",{pre:!0,attrs:{class:"token class-name"}},[s._v("Stream")]),t("span",{pre:!0,attrs:{class:"token generics"}},[t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("<")]),t("span",{pre:!0,attrs:{class:"token class-name"}},[s._v("String")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(">")])]),s._v(" streamOne "),t("span",{pre:!0,attrs:{class:"token operator"}},[s._v("=")]),s._v(" one"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(".")]),t("span",{pre:!0,attrs:{class:"token function"}},[s._v("stream")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("(")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(")")]),s._v("\n                "),t("span",{pre:!0,attrs:{class:"token comment"}},[s._v("// 1. 第一个队伍只要名字为3个字的成员姓名")]),s._v("\n                "),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(".")]),t("span",{pre:!0,attrs:{class:"token function"}},[s._v("filter")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("(")]),s._v("name "),t("span",{pre:!0,attrs:{class:"token operator"}},[s._v("->")]),s._v(" name"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(".")]),t("span",{pre:!0,attrs:{class:"token function"}},[s._v("length")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("(")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(")")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token operator"}},[s._v("==")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token number"}},[s._v("3")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(")")]),s._v("\n                "),t("span",{pre:!0,attrs:{class:"token comment"}},[s._v("// 2. 第一个队伍筛选之后只要前3个人")]),s._v("\n                "),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(".")]),t("span",{pre:!0,attrs:{class:"token function"}},[s._v("limit")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("(")]),t("span",{pre:!0,attrs:{class:"token number"}},[s._v("3")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(")")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(";")]),s._v("\n    \n        "),t("span",{pre:!0,attrs:{class:"token class-name"}},[s._v("Stream")]),t("span",{pre:!0,attrs:{class:"token generics"}},[t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("<")]),t("span",{pre:!0,attrs:{class:"token class-name"}},[s._v("String")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(">")])]),s._v(" streamTwo "),t("span",{pre:!0,attrs:{class:"token operator"}},[s._v("=")]),s._v(" two"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(".")]),t("span",{pre:!0,attrs:{class:"token function"}},[s._v("stream")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("(")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(")")]),s._v("\n                "),t("span",{pre:!0,attrs:{class:"token comment"}},[s._v("// 3. 第二个队伍只要姓张的成员姓名")]),s._v("\n                "),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(".")]),t("span",{pre:!0,attrs:{class:"token function"}},[s._v("filter")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("(")]),s._v("name "),t("span",{pre:!0,attrs:{class:"token operator"}},[s._v("->")]),s._v(" name"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(".")]),t("span",{pre:!0,attrs:{class:"token function"}},[s._v("startsWith")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("(")]),t("span",{pre:!0,attrs:{class:"token string"}},[s._v('"张"')]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(")")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(")")]),s._v("\n                "),t("span",{pre:!0,attrs:{class:"token comment"}},[s._v("// 4. 第二个队伍筛选之后不要前2个人")]),s._v("\n                "),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(".")]),t("span",{pre:!0,attrs:{class:"token function"}},[s._v("skip")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("(")]),t("span",{pre:!0,attrs:{class:"token number"}},[s._v("2")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(")")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(";")]),s._v("\n        "),t("span",{pre:!0,attrs:{class:"token comment"}},[s._v("// 5. 将两个队伍合并为一个队伍")]),s._v("\n        "),t("span",{pre:!0,attrs:{class:"token class-name"}},[s._v("Stream")]),t("span",{pre:!0,attrs:{class:"token generics"}},[t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("<")]),t("span",{pre:!0,attrs:{class:"token class-name"}},[s._v("String")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(">")])]),s._v(" stream "),t("span",{pre:!0,attrs:{class:"token operator"}},[s._v("=")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token class-name"}},[s._v("Stream")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(".")]),t("span",{pre:!0,attrs:{class:"token function"}},[s._v("concat")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("(")]),s._v("streamOne"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(",")]),s._v(" streamTwo"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(")")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(";")]),s._v("\n        "),t("span",{pre:!0,attrs:{class:"token comment"}},[s._v("// 6. 根据姓名创建 Person 对象")]),s._v("\n        stream"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(".")]),t("span",{pre:!0,attrs:{class:"token function"}},[s._v("map")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("(")]),t("span",{pre:!0,attrs:{class:"token class-name"}},[s._v("Person")]),t("span",{pre:!0,attrs:{class:"token operator"}},[s._v("::")]),t("span",{pre:!0,attrs:{class:"token keyword"}},[s._v("new")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(")")]),s._v("\n                "),t("span",{pre:!0,attrs:{class:"token comment"}},[s._v("// 7. 打印整个队伍的Person对象信息")]),s._v("\n                "),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(".")]),t("span",{pre:!0,attrs:{class:"token function"}},[s._v("forEach")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("(")]),t("span",{pre:!0,attrs:{class:"token class-name"}},[s._v("System")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(".")]),s._v("out"),t("span",{pre:!0,attrs:{class:"token operator"}},[s._v("::")]),t("span",{pre:!0,attrs:{class:"token function"}},[s._v("println")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(")")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(";")]),s._v("\n    "),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("}")]),s._v("\n"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("}")]),s._v("\n")])]),s._v(" "),t("div",{staticClass:"line-numbers-wrapper"},[t("span",{staticClass:"line-number"},[s._v("1")]),t("br"),t("span",{staticClass:"line-number"},[s._v("2")]),t("br"),t("span",{staticClass:"line-number"},[s._v("3")]),t("br"),t("span",{staticClass:"line-number"},[s._v("4")]),t("br"),t("span",{staticClass:"line-number"},[s._v("5")]),t("br"),t("span",{staticClass:"line-number"},[s._v("6")]),t("br"),t("span",{staticClass:"line-number"},[s._v("7")]),t("br"),t("span",{staticClass:"line-number"},[s._v("8")]),t("br"),t("span",{staticClass:"line-number"},[s._v("9")]),t("br"),t("span",{staticClass:"line-number"},[s._v("10")]),t("br"),t("span",{staticClass:"line-number"},[s._v("11")]),t("br"),t("span",{staticClass:"line-number"},[s._v("12")]),t("br"),t("span",{staticClass:"line-number"},[s._v("13")]),t("br"),t("span",{staticClass:"line-number"},[s._v("14")]),t("br"),t("span",{staticClass:"line-number"},[s._v("15")]),t("br"),t("span",{staticClass:"line-number"},[s._v("16")]),t("br"),t("span",{staticClass:"line-number"},[s._v("17")]),t("br"),t("span",{staticClass:"line-number"},[s._v("18")]),t("br"),t("span",{staticClass:"line-number"},[s._v("19")]),t("br"),t("span",{staticClass:"line-number"},[s._v("20")]),t("br"),t("span",{staticClass:"line-number"},[s._v("21")]),t("br"),t("span",{staticClass:"line-number"},[s._v("22")]),t("br"),t("span",{staticClass:"line-number"},[s._v("23")]),t("br"),t("span",{staticClass:"line-number"},[s._v("24")]),t("br"),t("span",{staticClass:"line-number"},[s._v("25")]),t("br"),t("span",{staticClass:"line-number"},[s._v("26")]),t("br")])]),t("h3",{attrs:{id:"_1-6-收集stream流中的结果"}},[t("a",{staticClass:"header-anchor",attrs:{href:"#_1-6-收集stream流中的结果"}},[s._v("#")]),s._v(" 1.6 收集Stream流中的结果")]),s._v(" "),t("ul",[t("li",[s._v("对流操作完成之后，如果需要将流的结果保存到数组或集合中，可以收集流中的数据")])]),s._v(" "),t("h4",{attrs:{id:"收集结果到集合中"}},[t("a",{staticClass:"header-anchor",attrs:{href:"#收集结果到集合中"}},[s._v("#")]),s._v(" 收集结果到集合中")]),s._v(" "),t("ul",[t("li",[s._v("Stream流提供 collect 方法，其参数需要一个"),t("code",[s._v("java.util.stream.Collector<T,A, R>")]),s._v("接口对象来指定收集到哪种集合中。"),t("code",[s._v("java.util.stream.Collectors")]),s._v("类提供一些方法，可以作为Collector`接口的实例：\n"),t("ul",[t("li",[t("code",[s._v("public static <T> Collector<T, ?, List<T>> toList()")]),s._v(": 转换为 List 集合")]),s._v(" "),t("li",[t("code",[s._v("public static <T> Collector<T, ?, Set<T>> toSet()")]),s._v(": 转换为 Set 集合")]),s._v(" "),t("li",[t("code",[s._v("public static <T, C extends Collection<T>> Collector<T, ?, C> toCollection(Supplier<C> collectionFactory)")]),s._v(": 收集到指定的集合中")])])])]),s._v(" "),t("h4",{attrs:{id:"收集结果到数组中"}},[t("a",{staticClass:"header-anchor",attrs:{href:"#收集结果到数组中"}},[s._v("#")]),s._v(" 收集结果到数组中")]),s._v(" "),t("ul",[t("li",[s._v("Stream提供 toArray 方法来将结果放到一个数组中")])]),s._v(" "),t("div",{staticClass:"language-text line-numbers-mode"},[t("pre",{pre:!0,attrs:{class:"language-text"}},[t("code",[s._v("Object[] toArray(); // 返回Object数组\n&lt;A> A[] toArray(IntFunction&lt;A[]> generator); // 返回指定数组\n")])]),s._v(" "),t("div",{staticClass:"line-numbers-wrapper"},[t("span",{staticClass:"line-number"},[s._v("1")]),t("br"),t("span",{staticClass:"line-number"},[s._v("2")]),t("br")])]),t("h4",{attrs:{id:"对流中数据进行聚合计算"}},[t("a",{staticClass:"header-anchor",attrs:{href:"#对流中数据进行聚合计算"}},[s._v("#")]),s._v(" 对流中数据进行聚合计算")]),s._v(" "),t("ul",[t("li",[s._v("当我们使用Stream流处理数据后，可以像数据库的聚合函数一样对某个字段进行操作。比如获取最大值，获取最小值，求总和，平均值，统计数量。")])]),s._v(" "),t("div",{staticClass:"language-java line-numbers-mode"},[t("pre",{pre:!0,attrs:{class:"language-java"}},[t("code",[t("span",{pre:!0,attrs:{class:"token keyword"}},[s._v("public")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token keyword"}},[s._v("class")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token class-name"}},[s._v("StreamCollectTest")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("{")]),s._v("\n    "),t("span",{pre:!0,attrs:{class:"token annotation punctuation"}},[s._v("@Test")]),s._v("\n    "),t("span",{pre:!0,attrs:{class:"token keyword"}},[s._v("public")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token keyword"}},[s._v("void")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token function"}},[s._v("aggregation")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("(")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(")")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("{")]),s._v("\n        "),t("span",{pre:!0,attrs:{class:"token class-name"}},[s._v("List")]),t("span",{pre:!0,attrs:{class:"token generics"}},[t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("<")]),t("span",{pre:!0,attrs:{class:"token class-name"}},[s._v("Person")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(">")])]),s._v(" personList "),t("span",{pre:!0,attrs:{class:"token operator"}},[s._v("=")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token class-name"}},[s._v("Stream")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(".")]),t("span",{pre:!0,attrs:{class:"token function"}},[s._v("of")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("(")]),s._v("\n                        "),t("span",{pre:!0,attrs:{class:"token keyword"}},[s._v("new")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token class-name"}},[s._v("Person")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("(")]),t("span",{pre:!0,attrs:{class:"token string"}},[s._v('"张三"')]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(",")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token number"}},[s._v("18")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(")")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(",")]),s._v("\n                        "),t("span",{pre:!0,attrs:{class:"token keyword"}},[s._v("new")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token class-name"}},[s._v("Person")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("(")]),t("span",{pre:!0,attrs:{class:"token string"}},[s._v('"李四"')]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(",")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token number"}},[s._v("22")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(")")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(",")]),s._v("\n                        "),t("span",{pre:!0,attrs:{class:"token keyword"}},[s._v("new")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token class-name"}},[s._v("Person")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("(")]),t("span",{pre:!0,attrs:{class:"token string"}},[s._v('"王五"')]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(",")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token number"}},[s._v("17")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(")")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(",")]),s._v("\n                        "),t("span",{pre:!0,attrs:{class:"token keyword"}},[s._v("new")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token class-name"}},[s._v("Person")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("(")]),t("span",{pre:!0,attrs:{class:"token string"}},[s._v('"小红"')]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(",")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token number"}},[s._v("19")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(")")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(",")]),s._v("\n                        "),t("span",{pre:!0,attrs:{class:"token keyword"}},[s._v("new")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token class-name"}},[s._v("Person")]),t("span",{pre:!0,attrs:{class:"token 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punctuation"}},[s._v(")")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(";")]),s._v("\n\n        "),t("span",{pre:!0,attrs:{class:"token comment"}},[s._v("// 获取最大值")]),s._v("\n        "),t("span",{pre:!0,attrs:{class:"token class-name"}},[s._v("Optional")]),t("span",{pre:!0,attrs:{class:"token generics"}},[t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("<")]),t("span",{pre:!0,attrs:{class:"token class-name"}},[s._v("Person")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(">")])]),s._v(" optional "),t("span",{pre:!0,attrs:{class:"token operator"}},[s._v("=")]),s._v(" personList"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(".")]),t("span",{pre:!0,attrs:{class:"token function"}},[s._v("stream")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("(")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(")")]),s._v("\n                "),t("span",{pre:!0,attrs:{class:"token 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"')]),s._v(" "),t("span",{pre:!0,attrs:{class:"token operator"}},[s._v("+")]),s._v(" optional"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(".")]),t("span",{pre:!0,attrs:{class:"token function"}},[s._v("get")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("(")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(")")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(")")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(";")]),s._v("\n\n        "),t("span",{pre:!0,attrs:{class:"token comment"}},[s._v("// 获取最小值")]),s._v("\n        "),t("span",{pre:!0,attrs:{class:"token class-name"}},[s._v("Optional")]),t("span",{pre:!0,attrs:{class:"token generics"}},[t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("<")]),t("span",{pre:!0,attrs:{class:"token class-name"}},[s._v("Person")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(">")])]),s._v(" optionalMin "),t("span",{pre:!0,attrs:{class:"token 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punctuation"}},[s._v(")")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(",")]),s._v("\n                    "),t("span",{pre:!0,attrs:{class:"token keyword"}},[s._v("new")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token class-name"}},[s._v("Person")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("(")]),t("span",{pre:!0,attrs:{class:"token string"}},[s._v('"小明"')]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(",")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token number"}},[s._v("21")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(")")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(")")]),s._v("\n                "),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(".")]),t("span",{pre:!0,attrs:{class:"token function"}},[s._v("collect")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("(")]),t("span",{pre:!0,attrs:{class:"token class-name"}},[s._v("Collectors")]),t("span",{pre:!0,attrs:{class:"token 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class-name"}},[s._v("Collectors")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(".")]),t("span",{pre:!0,attrs:{class:"token function"}},[s._v("groupingBy")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("(")]),t("span",{pre:!0,attrs:{class:"token class-name"}},[s._v("Person")]),t("span",{pre:!0,attrs:{class:"token operator"}},[s._v("::")]),t("span",{pre:!0,attrs:{class:"token function"}},[s._v("getAge")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(")")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(")")]),s._v("\n                "),t("span",{pre:!0,attrs:{class:"token comment"}},[s._v("// 分组结果为键值对")]),s._v("\n                "),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(".")]),t("span",{pre:!0,attrs:{class:"token function"}},[s._v("forEach")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("(")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("(")]),s._v("key"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(",")]),s._v(" value"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(")")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token operator"}},[s._v("->")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token class-name"}},[s._v("System")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(".")]),s._v("out"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(".")]),t("span",{pre:!0,attrs:{class:"token function"}},[s._v("println")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("(")]),s._v("key "),t("span",{pre:!0,attrs:{class:"token operator"}},[s._v("+")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token string"}},[s._v('"::"')]),s._v(" "),t("span",{pre:!0,attrs:{class:"token operator"}},[s._v("+")]),s._v(" value"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(")")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(")")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(";")]),s._v("\n\n        "),t("span",{pre:!0,attrs:{class:"token comment"}},[s._v("// 将年龄大于19的分为一组, 小于19分为一组")]),s._v("\n        personList"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(".")]),t("span",{pre:!0,attrs:{class:"token function"}},[s._v("stream")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("(")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(")")]),s._v("\n                "),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(".")]),t("span",{pre:!0,attrs:{class:"token function"}},[s._v("collect")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("(")]),t("span",{pre:!0,attrs:{class:"token class-name"}},[s._v("Collectors")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(".")]),t("span",{pre:!0,attrs:{class:"token function"}},[s._v("groupingBy")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("(")]),s._v("s "),t("span",{pre:!0,attrs:{class:"token operator"}},[s._v("->")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("{")]),s._v("\n                    "),t("span",{pre:!0,attrs:{class:"token keyword"}},[s._v("if")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("(")]),s._v("s"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(".")]),t("span",{pre:!0,attrs:{class:"token function"}},[s._v("getAge")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("(")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(")")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token operator"}},[s._v(">")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token number"}},[s._v("19")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(")")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("{")]),s._v("\n                        "),t("span",{pre:!0,attrs:{class:"token keyword"}},[s._v("return")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token string"}},[s._v('">=19"')]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(";")]),s._v("\n                    "),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("}")]),t("span",{pre:!0,attrs:{class:"token keyword"}},[s._v("else")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("{")]),s._v("\n                        "),t("span",{pre:!0,attrs:{class:"token keyword"}},[s._v("return")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token string"}},[s._v('"<19"')]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(";")]),s._v("\n                    "),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("}")]),s._v("\n                "),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("}")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(")")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(")")]),s._v("\n                "),t("span",{pre:!0,attrs:{class:"token comment"}},[s._v("// 分组结果为键值对, 键为groupingBy返回的数据")]),s._v("\n                "),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(".")]),t("span",{pre:!0,attrs:{class:"token function"}},[s._v("forEach")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("(")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("(")]),s._v("k"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(",")]),s._v(" v"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(")")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token operator"}},[s._v("->")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token class-name"}},[s._v("System")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(".")]),s._v("out"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(".")]),t("span",{pre:!0,attrs:{class:"token function"}},[s._v("println")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("(")]),s._v("k "),t("span",{pre:!0,attrs:{class:"token operator"}},[s._v("+")]),s._v(" 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punctuation"}},[s._v("(")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(")")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token operator"}},[s._v(">")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token number"}},[s._v("19")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(")")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("{")]),s._v("\n                            "),t("span",{pre:!0,attrs:{class:"token keyword"}},[s._v("return")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token string"}},[s._v('"大于19"')]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(";")]),s._v("\n                        "),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("}")]),t("span",{pre:!0,attrs:{class:"token keyword"}},[s._v("else")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("{")]),s._v("\n                            "),t("span",{pre:!0,attrs:{class:"token keyword"}},[s._v("return")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token string"}},[s._v('"小于等于19"')]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(";")]),s._v("\n                        "),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("}")]),s._v("\n                    "),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("}")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(",")]),s._v("\n                    "),t("span",{pre:!0,attrs:{class:"token comment"}},[s._v("// 根据名字长度分组")]),s._v("\n                    "),t("span",{pre:!0,attrs:{class:"token class-name"}},[s._v("Collectors")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(".")]),t("span",{pre:!0,attrs:{class:"token function"}},[s._v("groupingBy")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("(")]),s._v("p "),t("span",{pre:!0,attrs:{class:"token operator"}},[s._v("->")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("{")]),s._v("\n                        "),t("span",{pre:!0,attrs:{class:"token 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"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(")")]),s._v("\n                "),t("span",{pre:!0,attrs:{class:"token comment"}},[s._v("// 结果的类型为: Map<String, Map<String, Person>>")]),s._v("\n                "),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(".")]),t("span",{pre:!0,attrs:{class:"token function"}},[s._v("forEach")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("(")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("(")]),s._v("oneK"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(",")]),s._v(" oneV"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(")")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token operator"}},[s._v("->")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("{")]),s._v("\n                    "),t("span",{pre:!0,attrs:{class:"token class-name"}},[s._v("System")]),t("span",{pre:!0,attrs:{class:"token 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"),t("span",{pre:!0,attrs:{class:"token operator"}},[s._v("->")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("{")]),s._v("\n                        "),t("span",{pre:!0,attrs:{class:"token class-name"}},[s._v("System")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(".")]),s._v("out"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(".")]),t("span",{pre:!0,attrs:{class:"token function"}},[s._v("println")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("(")]),t("span",{pre:!0,attrs:{class:"token string"}},[s._v('"\\t"')]),s._v(" "),t("span",{pre:!0,attrs:{class:"token operator"}},[s._v("+")]),s._v(" twoK "),t("span",{pre:!0,attrs:{class:"token operator"}},[s._v("+")]),s._v(" "),t("span",{pre:!0,attrs:{class:"token string"}},[s._v('"::"')]),s._v(" "),t("span",{pre:!0,attrs:{class:"token operator"}},[s._v("+")]),s._v(" twoV"),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(")")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(";")]),s._v("\n                    "),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("}")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(")")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(";")]),s._v("\n                "),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v("}")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(")")]),t("span",{pre:!0,attrs:{class:"token punctuation"}},[s._v(";")]),s._v("\n        "),t("span",{pre:!0,attrs:{class:"token comment"}},[s._v("/*\n         result -> {\n            年龄小于等于19\n                较长的名字::[Person{name='迪迦奥特曼', age=18}]\n                较短的名字::[Person{name='张三丰', age=18}, Person{name='古力娜扎', age=18}]\n            年龄大于19\n                较长的名字::[Person{name='宇宙无敌法外狂徒张三', age=21}]\n                较短的名字::[Person{name='迪丽热巴', age=22}]\n         }\n        */")]),s._v("\n    "),t("span",{pre:!0,attrs:{class:"token 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