Question

java高手请进

import java.io.*;interface Worker{ public void doSomeWork(); }class Plumber implements Worker{ public void doSomeWork(){ System.out.println("水管工"); }class Carpenter implements Worker{ public void doSomeWork(){ System.out.println("木匠"); } class Aworker implements Worker{ public Worker worker; public Aworker(Worker worker){ this.worker= worker; } @Override public void doSomeWork() { // TODO Auto-generated method stub System.out.println("你好！"); worker.doSomeWork(); } } }}public class Test2 { public static void main(String[] args){ Plumber plumber= new Plumber(); Aworker aworker = new Aworker(plumber); aworker.doSomeWork(); }}eclipse的提示是要我新建一个Awork类，，，我新建以后确实没有问题了，这是为什么呢？，弄成下面这样就可以了。。为什么放在同一个java代码里不行

Answer 1

你是在学习内部类的只是吧？你定义的这3个类的关系是Plumber有内部类Carpenter，Carpenter又有内部类Aworker。所以你声明Aworker的时候应该这样声明：

import java.io.*;

interface Worker {
	public void doSomeWork();
}

class Plumber implements Worker {
	public void doSomeWork() {
		System.out.println("水管工");
	}

	class Carpenter implements Worker {
		public void doSomeWork() {
			System.out.println("木匠");
		}

		class Aworker implements Worker {
			public Worker worker;

			public Aworker(Worker worker) {
				this.worker = worker;
			}

			@Override
			public void doSomeWork() {
				// TODO Auto-generated method stub
				System.out.println("你好！");
				worker.doSomeWork();
			}
		}
	}
}

public class Test2 {
	public static void main(String[] args) {
		Plumber plumber = new Plumber();
		Plumber.Carpenter carpenter = plumber.new Carpenter();
		Plumber.Carpenter.Aworker aworker = carpenter.new Aworker(plumber);
		aworker.doSomeWork();
	}
}

Answer 2

你把Aworker放到Carpenter类里了,放到外面就可以了
class Carpenter implements Worker{
public void doSomeWork(){
System.out.println("木匠");
}

}
class Aworker implements Worker{
public Worker worker;
public Aworker(Worker worker){
this.worker= worker;
}
@Override
public void doSomeWork() {
// TODO Auto-generated method stub
System.out.println("你好！");
worker.doSomeWork();
}
}

Answer 3

一个java文件中 只能有一个 public 的class，接口类默认就是public

Answer 4

你把Aworker写到Carpenter类里面去了，成为了一个成员内部类，那么你在Main方法里能直接new它吗？