修改 getter 的结果会影响对象本身吗? [英] Does modifying the result of a getter affect the object itself?

问题描述

我有一个关于在 Java 中使用 getter 方法的问题.假设我有这门课:

I have a question about using getter methods in java. Suppose I had this class:

class Test {
    private ArrayList<String> array = new ArrayList<String>();

    public ArrayList getArray() {
        return this.array;
    }

    public void initArray() {
        array.add("Test 1");
        array.add("Test 2");
    }
}

class Start {
    public static void main(String args[]) {
        initArray();
        getArray().remove(0);
    }
} 

我的问题是:

实际的arraylist 对象是否会被修改(测试1"从中删除)?我想我已经在某些地方看到过这种情况，但我认为 getter 只是提供了该对象的副本.不是对它的引用.如果它确实以这种方式工作(作为参考)，那么这是否也有效(Test 类的 arraylist 对象是否也会由此改变)?:

Would the actual arraylist object be modified ("Test 1" removed from it)? I think I have seen this in places, but I thought that getters were simply providing a copy of that object. Not a reference to it. If it did work that way (as a reference), then would this work as well (Would the arraylist object of the class Test be altered by this as well)?:

class Start {
    public static void main(String args[]) {
        initArray();
        ArrayList aVar = getArray();
        aVar.remove(0);
    }
} 

推荐答案

Java 返回对 Array 的引用，因此它不会是副本，而是会修改 List.通常，除非它是原始类型(int、float 等)，否则您将获得对对象的引用.

Java returns references to the Array, so it won't be a copy and it will modify the List. In general, unless its a primitive type (int,float,etc) you will be getting a reference to the object.

如果你想返回一个重复的数组，你必须自己显式复制数组.

You have to explicitly copy the array yourself if you want a duplicate to be returned.

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