线程总结(二)

/*
 * 线程同步的例子
 * 
 */
public class Test {
    public static void main(String[] args) {
        //创建两个线程并执行同一条语句
        Run r=new Run();
        Thread t1=new Thread(r,"t1");
        Thread t2=new Thread(r,"t2");
        t1.start();
        t2.start();

    }
}


class Run implements Runnable{
    Timer t=new Timer();


    //两个开始的线程调用同一个类中的方法
    public void run(){
        t.add(Thread.currentThread().getName());
    }
}


class Timer{

    int num=0;               //计数
    Thread t=new Thread();
    //当第一个线程执行完计数，睡眠1ms时，第二个线程开始执行计数并睡眠1ms，然后第一个线程打印，
    //接着第二个线程打印,打印时计数以累加到2.
    public void add(String ThreadName){
        num++;        
        try {
            t.sleep(1);
        } catch (InterruptedException e) { }
        System.out.println(ThreadName+"第"+num+"次执行");
    }


}

/*
 * 避免线程同步。
 * 
 */
public class Test {
    public static void main(String[] args) {
        //创建两个线程并执行同一条语句
        Run r=new Run();
        Thread t1=new Thread(r,"t1");
        Thread t2=new Thread(r,"t2");
        t1.start();
        t2.start();

    }
}


class Run implements Runnable{
    Timer t=new Timer();


    //两个开始的线程调用同一个类中的方法
    public void run(){
        t.add(Thread.currentThread().getName());
    }
}


class Timer{

    int num=0;               //计数
    Thread t=new Thread();
    public  synchronized  void add(String ThreadName){
        //通过关键字synchronized，在执行方法的过程中锁定当前对象。
    //    synchronized (this){
            num++;        
            try {
                t.sleep(1);
            } catch (InterruptedException e) { }
            System.out.println(ThreadName+"第"+num+"次执行");
        //}
    }


}

/*
 * 线程死锁
 * 
 */
public class Test {
    public static void main(String[] args) {
        //创建两个线程执行不同语句
        Run r1=new Run();
        Run r2=new Run();
        r1.flag=1;
        r2.flag=0;
        Thread t1=new Thread(r1);
        Thread t2=new Thread(r2);
        t1.start();
        t2.start();

    }
}


class Run implements Runnable{

    int flag=1;                   //通过flag的值区分两个不同线程执行的不同操作
    static Object o1=new Object(),o2=new Object();
    
    //flag==1的线程无法得到o2，flag==0的线程无法得到o1，进入死锁状态
    public void run(){
        System.out.println("flag="+flag);
        //flag==1的线程先锁住o1，在锁o2
        if(flag==1){
            synchronized(o1){
                try {
                    Thread.sleep(500);
                } catch (InterruptedException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
                synchronized(o2){
                    System.out.println("1");
                }
            }
        }
            //flag==1的线程先锁住o2，在锁o1
            if(flag==0){
                synchronized(o2){
                    try {
                        Thread.sleep(500);
                    } catch (InterruptedException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }
                    synchronized(o1){
                        System.out.println("0");
                    }

                }
            }
        }
    }

/*
 * 线程死锁
 * 
 */
public class Test {
    public static void main(String[] args) {
        //创建一个线程执行语句
        Run r=new Run();
        Thread t=new Thread(r);
        t.start();
        
        //使线程锁定run()
        try {
            Thread.sleep(1000);
        } catch (InterruptedException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        r.getb();

    }
}


class Run implements Runnable{
    int b=100;

    public void run(){
        synchronized(this){
            b=1000;
            try {
                Thread.sleep(5000);
            } catch (InterruptedException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            System.out.println("runner:b="+b);
        }
    }
    
    public void getb(){
        System.out.println("m2:b="+b);
    }

}

/*
 * 线程死锁
 * 
 */
public class Test {
    public static void main(String[] args) {
        
        Run r=new Run();
        Thread t=new Thread(r);
        t.start();

        
        try {
            Thread.sleep(8000);
        } catch (InterruptedException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        
        r.m2();
        System.out.println(r.b);

    }
}


class Run implements Runnable{
    int b=100;

    public synchronized void m1(){
        b=1000;

        try {
            Thread.sleep(5000);
        } catch (InterruptedException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
    public void run(){
        m1();
        System.out.println("runner:b="+b);

    }

    public synchronized void m2(){
        b=2000;
        System.out.println("m2:b="+b);
    }
}