静态工具方法的并发控制

静态工具方法并发时候不能简单的用同步关键字来同步方法，因为静态方法是类级别的方法，锁定的是这个类class本身，这样的结果就是任何一个同步的静态方法运行，都会导致其他同步方法调用的阻塞。这个也是问题所在。

这里给出一个简单的方法来避免这个问题：

通过给每个方法一个锁来控制并发，就可以巧妙的解决阻塞问题。

import java.util.concurrent.locks.Lock; 
import java.util.concurrent.locks.ReentrantLock; 
  
/** 
 * 静态工具方法的并发控制 
 * 
 * @author leizhimin 2014/7/19 17:18 
 */
public class Test { 
    private static final Lock lock1 = new ReentrantLock(); 
    private static final Lock lock2 = new ReentrantLock(); 
  
    public static void t1() throws InterruptedException { 
        lock1.lock(); 
        System.out.println(Thread.currentThread().getName() + ": t1..."); 
        Thread.sleep(500L); 
        lock1.unlock(); 
    } 
  
    public static void t2() throws InterruptedException { 
        lock2.lock(); 
        System.out.println(Thread.currentThread().getName() + ": t2..."); 
        lock2.unlock(); 
    } 
  
    public static void main(String[] args) { 
        new Thread(new Runnable() { 
            @Override
            public void run() { 
                try { 
                    t1(); 
                } catch (InterruptedException e) { 
                    e.printStackTrace(); 
                } 
            } 
        }).start(); 
        new Thread(new Runnable() { 
            @Override
            public void run() { 
                try { 
                    t1(); 
                } catch (InterruptedException e) { 
                    e.printStackTrace(); 
                } 
            } 
        }).start(); 
        new Thread(new Runnable() { 
            @Override
            public void run() { 
                try { 
                    t1(); 
                } catch (InterruptedException e) { 
                    e.printStackTrace(); 
                } 
            } 
        }).start(); 
  
        new Thread(new Runnable() { 
            @Override
            public void run() { 
                try { 
                    t2(); 
                } catch (InterruptedException e) { 
                    e.printStackTrace(); 
                } 
            } 
        }).start(); 
        new Thread(new Runnable() { 
            @Override
            public void run() { 
                try { 
                    t2(); 
                } catch (InterruptedException e) { 
                    e.printStackTrace(); 
                } 
            } 
        }).start(); 
        new Thread(new Runnable() { 
            @Override
            public void run() { 
                try { 
                    t2(); 
                } catch (InterruptedException e) { 
                    e.printStackTrace(); 
                } 
            } 
        }).start(); 
    } 
} 

123456789 D:\jdk1.7.0_55\bin\java 。。。 
Thread-0: t1... 
Thread-3: t2... 
Thread-4: t2... 
Thread-5: t2... 
Thread-2: t1... 
Thread-1: t1... 
  
Process finished with exit code 0