使用synchronized和Lock对象获取对象锁

public class Resource3 {
    private Lock lock = new ReentrantLock();

    public void f() {
       // other operations should not be locked...
       System.out.println(Thread.currentThread().getName()
              + ":not synchronized in f()");
       lock.lock();
       try {
           for (int i = 0; i < 5; i++) {
              System.out.println(Thread.currentThread().getName()
                     + ":synchronized in f()");
              try {
                  TimeUnit.SECONDS.sleep(3);
              } catch (InterruptedException e) {
                  e.printStackTrace();
              }
           }
       } finally {
           lock.unlock();
       }
    }

    public void g() {
       // other operations should not be locked...
       System.out.println(Thread.currentThread().getName()
              + ":not synchronized in g()");
       lock.lock();
       try {
           for (int i = 0; i < 5; i++) {
              System.out.println(Thread.currentThread().getName()
                     + ":synchronized in g()");
              try {
                  TimeUnit.SECONDS.sleep(3);
              } catch (InterruptedException e) {
                  e.printStackTrace();
              }
           }
       } finally {
           lock.unlock();
       }
    }

    public void h() {
       // other operations should not be locked...
       System.out.println(Thread.currentThread().getName()
              + ":not synchronized in h()");
       lock.lock();
       try {
           for (int i = 0; i < 5; i++) {
              System.out.println(Thread.currentThread().getName()
                     + ":synchronized in h()");
              try {
                  TimeUnit.SECONDS.sleep(3);
              } catch (InterruptedException e) {
                  e.printStackTrace();
              }
           }
       } finally {
           lock.unlock();
       }
    }

    public static void main(String[] args) {
       final Resource3 rs = new Resource3();

       new Thread() {
           public void run() {
              rs.f();
           }
       }.start();

       new Thread() {
           public void run() {
              rs.g();
           }
       }.start();

       rs.h();
        }
    }

    结果：
    Thread-0:not synchronized in f()
    Thread-0:synchronized in f()
    main:not synchronized in h()
    Thread-1:not synchronized in g()
    Thread-0:synchronized in f()
    Thread-0:synchronized in f()
    Thread-0:synchronized in f()
    Thread-0:synchronized in f()
    main:synchronized in h()
    main:synchronized in h()
    main:synchronized in h()
    main:synchronized in h()
    main:synchronized in h()
    Thread-1:synchronized in g()
    Thread-1:synchronized in g()
    Thread-1:synchronized in g()
    Thread-1:synchronized in g()
    Thread-1:synchronized in g()
    Resource4.java
    package com.zj.lock;
    import java.util.concurrent.TimeUnit;
    import java.util.concurrent.locks.Lock;
    import java.util.concurrent.locks.ReentrantLock;

    public class Resource4 {
        private Lock lock1 = new ReentrantLock();
        private Lock lock2 = new ReentrantLock();
        private Lock lock3 = new ReentrantLock();

        public void f() {
           // other operations should not be locked...
           System.out.println(Thread.currentThread().getName()
                  + ":not synchronized in f()");
           lock1.lock();
           try {
           for (int i = 0; i < 5; i++) {
              System.out.println(Thread.currentThread().getName()
                     + ":synchronized in f()");
              try {
                  TimeUnit.SECONDS.sleep(3);
              } catch (InterruptedException e) {
                  e.printStackTrace();
              }
           }
       } finally {
           lock1.unlock();
       }
    }

    public void g() {
       // other operations should not be locked...
       System.out.println(Thread.currentThread().getName()
              + ":not synchronized in g()");
       lock2.lock();
       try {
           for (int i = 0; i < 5; i++) {
              System.out.println(Thread.currentThread().getName()
                     + ":synchronized in g()");
              try {
                  TimeUnit.SECONDS.sleep(3);
              } catch (InterruptedException e) {
                  e.printStackTrace();
              }
           }
       } finally {
           lock2.unlock();
       }
    }

    public void h() {
       // other operations should not be locked...
       System.out.println(Thread.currentThread().getName()
              + ":not synchronized in h()");
       lock3.lock();
       try {
           for (int i = 0; i < 5; i++) {
              System.out.println(Thread.currentThread().getName()
                     + ":synchronized in h()");
              try {
                  TimeUnit.SECONDS.sleep(3);
              } catch (InterruptedException e) {
                  e.printStackTrace();
              }
           }
       } finally {
           lock3.unlock();
        }
     }

     public static void main(String[] args) {
       final Resource4 rs = new Resource4();

       new Thread() {
           public void run() {
              rs.f();
           }
       }.start();

       new Thread() {
           public void run() {
              rs.g();
           }
       }.start();

       rs.h();
       }
    }