java多线程

 创建线程的两种传统方式
  1).在Thread子类覆盖的run方法中编写运行代码

Thread thread1=new Thread(){
            @Override
            publicvoid run() {
                while(true){
                    try {
                        Thread.sleep(500);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                    System.out.println("0 : "+Thread.currentThread      ().getName());
                }
            }
        };

        thread1.start();

Thread thread1=new Thread(){
			@Override
			public void run() {
				while(true){
					try {
						Thread.sleep(500);
					} catch (InterruptedException e) {
						e.printStackTrace();
					}
					System.out.println("0 : "+Thread.currentThread		().getName());
				}
			}
		};
		
		thread1.start();

2).在传递给Thread对象的Runnable对象的run方法中编写代码

Thread thread2=new Thread(new Runnable() {

            @Override
            publicvoid run() {

                while(true){
                    try {
                        Thread.sleep(500);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                    System.out.println("1 : "+Thread.currentThread().getName());
                }
            }
        });
        thread2.start();

Thread thread2=new Thread(new Runnable() {
			
			@Override
			public void run() {
				
				while(true){
					try {
						Thread.sleep(500);
					} catch (InterruptedException e) {
						e.printStackTrace();
					}
					System.out.println("1 : "+Thread.currentThread().getName());
				}
			}
		});
		thread2.start();

总结：查看Thread类的run()方法的源代码，可以看到其实这两行方式都是在调用Thread对象的run方      法，如果Thread类的run方法没有被覆盖，并且为该Thread对象设置了一个Runnable对象，该run       方法会调用Runnable对象的run方法。
   如果在Thread子类覆盖的run方法中编写了运行代码，也为Thread子类对象传递了一个Runnable对象    ，那么，线程运行时的执行代码是子类的Run方法的代码。   

new Thread(new Runnable() {

        @Override
        publicvoid run() {
            while(true){
                try {
                    Thread.sleep(500);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                System.out.println("runnable : "+Thread.currentThread().getName());
            }

        }
    }){
        publicvoid run() {
            while(true){
                try {
                    Thread.sleep(500);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                System.out.println("thread : "+Thread.currentThread().getName());
            }
        };
    }.start();

	new Thread(new Runnable() {
			
			@Override
			public void run() {
				while(true){
					try {
						Thread.sleep(500);
					} catch (InterruptedException e) {
						e.printStackTrace();
					}
					System.out.println("runnable : "+Thread.currentThread().getName());
				}
				
			}
		}){
			public void run() {
				while(true){
					try {
						Thread.sleep(500);
					} catch (InterruptedException e) {
						e.printStackTrace();
					}
					System.out.println("thread : "+Thread.currentThread().getName());
				}
			};
		}.start();

输出结果为thread : Thread-2
2.定时器的应用    1)Timer类    2)TimerTask类

new Timer().schedule(new TimerTask() {

            @Override
            publicvoid run() {
                System.out.println("bombing");

            }
        }, 10000,3000);

new Timer().schedule(new TimerTask() {
			
			@Override
			public void run() {
				System.out.println("bombing");
				
			}
		}, 10000,3000);

3.线程的同步互斥与通信
  1)使用synchronized代码块及其原理 public  void output(String name){ synchronized (this) { for (int i = 0; i < name.length(); i++) { System.out.print(name.charAt(i)+" "); } System.out.println(); } }   2)使用synchronized方法 class OutPuter{ public synchronizedvoid output(String name){ for (int i = 0; i < name.length(); i++) { System.out.print(name.charAt(i)+" "); } System.out.println(); } }
面试题：子线程循环10次，接着主线程循环100次，接着又回到子线程循环10次，接着再回到主线程又         循环100次，如此循环50次，请写出程序。

publicclass TraditionalThreadCommunication {


    /**
     * @param args
     */
    publicstaticvoid main(String[] args) {

        final Business business=new Business();

        //子线程
        new Thread(new Runnable() {

            @Override
            publicvoid run() {
                for (int i = 1; i <=50; i++) {
                    business.sub(i);
                }
            }
        }).start();


        //主线程
        for (int i = 1; i <=50; i++) {
            business.main(i);
        }


    }


}


class Business{

    privateboolean bShouldSub=true;

    publicsynchronizedvoid sub(int i){
        while(!bShouldSub){
            try {
                this.wait();//等待
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
        for (int j = 1; j <= 10; j++) {
            System.out.println("sub thread sequence of " + j
                        + " , loop of " + i);
        }

        bShouldSub=false;
        this.notify();//唤醒（防止死锁）

    }
    publicsynchronizedvoid main(int i){
        while(bShouldSub){
            try {
                this.wait();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
        for (int j = 1; j <= 20; j++) {
            System.out.println("main thread sequence of " + j
                    + " , loop of " + i);
        }

        bShouldSub=true;
        this.notify();
    }

}

public class TraditionalThreadCommunication {


	/**
	 * @param args
	 */
	public static void main(String[] args) {
		
		final Business business=new Business();
		
	 	//子线程
		new Thread(new Runnable() {
			
			@Override
			public void run() {
				for (int i = 1; i <=50; i++) {
					business.sub(i);
			    }
			}
		}).start();
		
		
		//主线程
		for (int i = 1; i <=50; i++) {
			business.main(i);
	    }


	}


}


class Business{
	
	private boolean bShouldSub=true;
	
	public synchronized void sub(int i){
		while(!bShouldSub){
		    try {
				this.wait();//等待
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
		}
		for (int j = 1; j <= 10; j++) {
			System.out.println("sub thread sequence of " + j
						+ " , loop of " + i);
		}
		
		bShouldSub=false;
		this.notify();//唤醒（防止死锁）
		
	}
	public synchronized void main(int i){
		while(bShouldSub){
			try {
				this.wait();
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
		}
		for (int j = 1; j <= 20; j++) {
			System.out.println("main thread sequence of " + j
					+ " , loop of " + i);
		}
		
		bShouldSub=true;
		this.notify();
	}
	
}

   (总结：要用到共同数据（包括同步锁）的若干个方法，应该归在同一个类身上，这种设计正好体现了高类聚和程序的健壮性。)