安全多线程例子

package com.ygl;

public interface Output {
public void output(String str);

}

//**************************

package com.ygl;
public class Outputer implements Output{
  public void output(String str){
 int len=str.length();
synchronized(this) //或者用方法锁
    {
 for(int i=0;i<len;i++){
System.out.print(str.charAt(i));  
 }
 System.out.println();
 }
  }
}

或者

package com.ygl;


import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;


public class Outputer implements Output{
Lock lock=new ReentrantLock();
  public void output(String str){
 
 int len=str.length();
   lock.lock();
   try{
    for(int i=0;i<len;i++){
System.out.print(str.charAt(i));  
 }
 System.out.println();
   }finally{
    lock.unlock();
   }
 

  }
}

//************************************

package com.ygl;
public class MyRunnable implements Runnable{
   private  Output obj;
   private String str;
public  MyRunnable ( Output obj,String str){
    this.obj=obj;
    this.str=str;
    }
    public MyRunnable (){
   
    }
@Override
public void run() {
while(true){
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
obj.output(str);
}

}

}

//*********************************

package com.ygl;


public class TraditionalThreadSynchronized {
   public static void main(String[] args) {
Output output=new Outputer();
Runnable  runnable1 =new MyRunnable(output,"ygl"); 
Runnable  runnable2 =new MyRunnable(output,"liming"); 
Thread thread1=new Thread(runnable1);
thread1.start();
Thread thread2=new Thread(runnable2);
thread2.start();
}
}