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Java中的匿名內部類

通常通過繼承某個類或實現某個接口的方式來編寫代碼，但是有時候某一些代碼隻使用一次，就沒有必要寫專門寫一個子類或實現類了，可以采用匿名內部類的寫法。最常用的場景是線程方麵的應用。

一、不使用匿名內部類
①繼承
abstract class Player
{
public abstract void play();
}

public class FootBallPlayer extends Player
{
public void play()
{
System.out.println("踢足球");
}
}

public class AnonymousInnerClassTest
{
public static void main(String[] args)
{
Player p1 = new FootBallPlayer();
p1.play();
}
}

②接口
interface IPlayer
{
public void play();
}

public class IPlayFootballImpl implements IPlayer
{
public void play()
{
System.out.println("踢足球");
}
}

public class AnonymousInnerClassTest
{
public static void main(String[] args)
{
IPlayer ip1 = new IPlayFootballImpl();
ip1.play();
}
}


二、使用匿名內部類
①繼承
abstract class Player
{
public abstract void play();
}


public class AnonymousInnerClassTest
{
public static void main(String[] args)
{
Player p2 = new Player() {
public void play()
{
System.out.println("打籃球");
}
};
p2.play();
}
}

②接口
interface IPlayer
{
public void play();
}

public class AnonymousInnerClassTest
{
public static void main(String[] args)
{
IPlayer ip2 = new IPlayer() {
public void play()
{
System.out.println("打籃球");
}
};
}
}

三、線程中的應用
實現線程的方法有兩種：①繼承Thread類 ②實現Runnable接口。給出用匿名類實現的例子：

public class ThreadTest
{
public static void main(String[] args)
{
// 繼承Thread類
Thread thread = new Thread() {
@Override
public void run()
{
while (true)
{
try
{
Thread.sleep(1000);
System.out.println(Thread.currentThread().getName());
System.out.println(this.getName());
}
catch (InterruptedException e)
{
System.out.println(e.getMessage());
}
}
}
};
thread.start();

// 實現Runnable接口
Thread thread2 = new Thread(new Runnable() {
@Override
public void run()
{
while (true)
{
try
{
Thread.sleep(1000);
System.out.println(Thread.currentThread().getName());
}
catch (InterruptedException e)
{
System.out.println(e.getMessage());
}
}
}
});
thread2.start();
}
}

最後更新：2017-04-04 07:32:25

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