修改吸气剂的结果是否会影响对象本身? [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.假设我上了这个课:

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:

是否会修改实际的arraylist对象(从其中删除测试1")?我认为我已经在某些地方看到了这一点，但是我认为吸气剂只是提供了该物体的一个副本.没有引用它.如果它确实以这种方式起作用(作为参考)，那么它也会起作用(是否也会因此改变Test类的arraylist对象)?

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，因此它不是副本，它将修改List.通常，除非它是原始类型( int ， float 等)，否则您将获得对该对象的引用.

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.

如果要返回重复项，则必须自己明确地复制数组.

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

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