Java并发学习之十四——使用Lock同步代码块

Java提供另外的机制用来同步代码块。它比synchronized关键字更加强大、灵活。Lock 接口比synchronized关键字提供更多额外的功能。在使用Lock时需要注意的是要释放Lock锁。

package chapter2;  
  
import java.util.concurrent.locks.Lock;  
import java.util.concurrent.locks.ReentrantLock;  
  
/* 
 * 打印队列 
 */  
public class PrintQueue {  
    private final Lock queueLock = new ReentrantLock();  
    public void printJob(Object document){  
        queueLock.lock();//获取Lock对象的控制权  
          
        try {  
            Long duration = (long)(Math.random()*10000);  
            System.out.println(Thread.currentThread().getName()  
                    +"PrintQueue:Printing a Job during "  
                    +(duration/1000)+" seconds");  
            Thread.sleep(duration);           
        } catch (Exception e) {  
            e.printStackTrace();  
        } finally{  
            queueLock.unlock();//释放Lock对象的控制  
        }  
    }  
}

package chapter2;  
  
public class Job implements Runnable{  
    private PrintQueue printQueue;  
    public Job(PrintQueue printQueue){  
        this.printQueue = printQueue;  
    }  
    @Override  
    public void run() {  
        System.out.printf("%s:Going to print a document\n",   
                Thread.currentThread().getName());  
        printQueue.printJob(new Object());  
        System.out.printf("%s:The document has been printed\n",Thread.currentThread().getName());  
    }  
      
      
}

package chapter2;  
/** 
 *  
 * <p> 
 * Description: 使用Lock同步代码块 
 * </p> 
 * @author zhangjunshuai 
 * @version 1.0 
 * Create Date: 2014-9-16 下午4:57:06 
 * Project Name: Java7Thread 
 * 
 * <pre> 
 * Modification History:  
  *             Date                                Author                   Version          Description  
 * -----------------------------------------------------------------------------------------------------------   
 * LastChange: $Date::             $      $Author: $          $Rev: $          
 * </pre> 
 * 
 */  
public class Main5 {  
  
    /** 
     * <p> 
     * </p> 
     * @author zhangjunshuai 
     * @date 2014-9-16 下午4:57:00 
     * @param args 
     */  
    public static void main(String[] args) {  
  
        PrintQueue printQueue = new PrintQueue();  
        Thread thread[] = new Thread[10];  
        for(int i=0;i<10;i++){  
            thread[i] = new Thread(new Job(printQueue),"Thread"+i);  
        }  
        for(int i=0;i<10;i++){  
            thread[i].start();  
        }  
    }  
  
}