修改原始列表对象的问题？ [英] Issue in modifying the objects of original list?

问题描述

我遇到问题临时列表也会在原始列表内容被更改时被修改。预期结果应为'Employ Original'。

I have faced problem temporary list is also modified while original list content is being changed. Expected result should be 'Employ Original'.

public static void main(String[] args) {

        List<Employ> e = new ArrayList<Employ>();
        e.add(new Employ("Employ Original"));
        //
        List<Employ> exList = new ArrayList<>(e);
        e.get(0).name = "Employ Modified";

        // Result should be 'Employ Original' 
        System.out.println("" + exList.get(0).name);
    }

    public static class Employ {
        public String name;

        public Employ(String str) {
            this.name = str;
        }
    }

推荐答案

你如果要复制，需要克隆原始对象。 ArrayList只为新列表创建新指针。指针仍然只指向原始对象。

You need to clone the original objects if you want copies. The ArrayList is only making new pointers for new lists. The pointers still only point to the original objects.

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