hashMap中如果里面有对用的key，则给value追加数据

?

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32

<code-pre class="code-pre" id="pre-JiP2re"><code-line class="line-numbers-rows"></code-line>    public static void main(String[] args) { <code-line class="line-numbers-rows"></code-line>        Map<Integer, List<Integer>> type2OtherData = new HashMap<>(); <code-line class="line-numbers-rows"></code-line>        List<Integer> i = new ArrayList<>(); <code-line class="line-numbers-rows"></code-line>        i.add(1); <code-line class="line-numbers-rows"></code-line>        type2OtherData.merge(1,i, (x,y) -> { <code-line class="line-numbers-rows"></code-line>            // x 为map中已有key对应的value值 <code-line class="line-numbers-rows"></code-line>            System.out.println("x: " + x); <code-line class="line-numbers-rows"></code-line>            // y 为此时输入的value，也就是此处的 i <code-line class="line-numbers-rows"></code-line>            System.out.println("y: " + y); <code-line class="line-numbers-rows"></code-line>            // 我这里是追加操作，自己可以根据情况修改 <code-line class="line-numbers-rows"></code-line>            x.addAll(y); <code-line class="line-numbers-rows"></code-line>            return x; <code-line class="line-numbers-rows"></code-line>        }); <code-line class="line-numbers-rows"></code-line>        List<Integer> ii = new ArrayList<>(); <code-line class="line-numbers-rows"></code-line>        ii.add(2); <code-line class="line-numbers-rows"></code-line>        type2OtherData.merge(1,ii, (x,y) -> { <code-line class="line-numbers-rows"></code-line>            System.out.println("x: " + x); <code-line class="line-numbers-rows"></code-line>            System.out.println("y: " + y); <code-line class="line-numbers-rows"></code-line>            x.addAll(y); <code-line class="line-numbers-rows"></code-line>            return x; <code-line class="line-numbers-rows"></code-line>        }); <code-line class="line-numbers-rows"></code-line>        List<Integer> iii = new ArrayList<>(); <code-line class="line-numbers-rows"></code-line>        iii.add(3); <code-line class="line-numbers-rows"></code-line>        type2OtherData.merge(1,iii, (x,y) -> { <code-line class="line-numbers-rows"></code-line>            System.out.println("x: " + x); <code-line class="line-numbers-rows"></code-line>            System.out.println("y: " + y); <code-line class="line-numbers-rows"></code-line>            x.addAll(y); <code-line class="line-numbers-rows"></code-line>            return x; <code-line class="line-numbers-rows"></code-line>        }); <code-line class="line-numbers-rows"></code-line>        System.out.println(type2OtherData); <code-line class="line-numbers-rows"></code-line>    } </code-pre>

　　打印

?

1 2 3 4 5 6

<code-pre class="code-pre" id="pre-YjRE5N"><code-line class="line-numbers-rows"></code-line>x: [1] <code-line class="line-numbers-rows"></code-line>y: [2] <code-line class="line-numbers-rows"></code-line>x: [1, 2] <code-line class="line-numbers-rows"></code-line>y: [3] <code-line class="line-numbers-rows"></code-line>{1=[1, 2, 3]} </code-pre>

　　

__EOF__

本文作者：东峰叵.com
本文链接：https://www.cnblogs.com/databank/p/18740362.html
关于博主：评论和私信会在第一时间回复。或者直接私信我。
版权声明：本博客所有文章除特别声明外，均采用 BY-NC-SA 许可协议。转载请注明出处！
声援博主：如果您觉得文章对您有帮助，可以点击文章右下角【推荐】一下。您的鼓励是博主的最大动力！