如何在Java中通过引用调用? [英] How to do call by reference in Java?
问题描述
由于Java不支持指针,如何通过Java中的引用来调用函数,就像在C和C ++中一样?
Since Java doesnt support pointers, How is it possible to call a function by reference in Java like we do in C and C++??
推荐答案
Java中不可能实现真正的pass-by-reference。 Java按值传递所有内容,包括引用。但您可以使用容器对象模拟它。
Real pass-by-reference is impossible in Java. Java passes everything by value, including references. But you can simulate it with container Objects.
使用其中任何一个作为方法参数:
Use any of these as a method parameter:
- 一个数组
- 一个集合
- 一个AtomicXYZ类
如果你在一个方法中改变它的内容,改变的内容将可用于调用上下文。
And if you change its contents in a method, the changed contents will be available to the calling context.
哎呀,你显然是指通过引用调用方法。这在Java中也是不可能的,因为方法在Java中不是一级公民。 这可能会在JDK 8中发生变化,但目前,您必须使用接口来解决此限制。
Oops, you apparently mean calling a method by reference. This is also not possible in Java, as methods are no first-level citizens in Java. This may change in JDK 8, but for the time being, you will have to use interfaces to work around this limitation.
public interface Foo{
void doSomeThing();
}
public class SomeFoo implements Foo{
public void doSomeThing(){
System.out.println("foo");
}
}
public class OtherFoo implements Foo{
public void doSomeThing(){
System.out.println("bar");
}
}
使用 Foo
在您的代码中,因此您可以轻松地将 SomeFoo
替换为 OtherFoo
。
Use Foo
in your code, so you can easily substitute SomeFoo
with OtherFoo
.
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