/** * @author admin * @date 2018/1/12 9:48 * 作用在同一个实例对象上讨论 * synchronized同步方法的测试 * 两个线程,一个线程调用synchronized修饰方法,另一个线程可以调用非synchronized修饰的方法,互不影响 */ public class SynchronizedTest { public synchronized void methodA() { try { for (int i = 0; i < 5; i++) { System.out.println("methodA-" + i); Thread.sleep(1000); } } catch (InterruptedException e) { e.printStackTrace(); } } public void methodB() { try { for (int i = 0; i < 5; i++) { System.out.println("methodB-" + i ); Thread.sleep(1000); } } catch (InterruptedException e) { e.printStackTrace(); } } public static void main(String[] args) { SynchronizedTest test = new SynchronizedTest(); Thread thread1 = new Thread(new Runnable() { @Override public void run() { test.methodA(); } }); thread1.start(); Thread thread2 = new Thread(new Runnable() { @Override public void run() { test.methodB(); } }); thread2.start(); } } 运行结果: methodA-0 methodB-0 methodA-1 methodB-1 methodB-2 methodA-2 methodA-3 methodB-3 methodA-4 methodB-4
/** * @author admin * @date 2018/1/12 10:16 * 作用在同一个实例对象上讨论 * Sychronized代码块的测试 * 两个线程,一个线程执行synchronized代码块,另一个线程执行非synchronized代码块 */ public class SychronizedTest2 { public void methodA() { synchronized (this) { try { for (int i = 0; i < 5; i++) { System.out.println("methodA-" + i); Thread.sleep(1000); } } catch (InterruptedException e) { e.printStackTrace(); } } } public void methodB() { try { for (int i = 0; i < 5; i++) { System.out.println("methodB-" + i); Thread.sleep(1000); } } catch (InterruptedException e) { e.printStackTrace(); } } public static void main(String[] args) { SychronizedTest2 test2 = new SychronizedTest2(); Thread thread1 = new Thread(new Runnable() { @Override public void run() { test2.methodA(); } }); thread1.start(); Thread thread2 = new Thread(new Runnable() { @Override public void run() { test2.methodB(); } }); thread2.start(); } } 运行结果: methodA-0 methodB-0 methodA-1 methodB-1 methodA-2 methodB-2 methodB-3 methodA-3 methodA-4 methodB-4
/** * @author admin * @date 2018/1/12 10:33 * 作用在同一个实例对象上讨论 * Synchronized同步方法和同步代码块 * 1、synchronized和synchronized(this)二者没区别,都作用在this对象锁上面,所以会同步 * 2、synchronized(obj),这个是作用在obj对象锁上面,和this对象锁不同,所以不会同步 */ public class SynchronizedTest3 { public synchronized void methodA() { try { for (int i = 0; i < 5; i++) { System.out.println("methodA-" + i); Thread.sleep(1000); } } catch (InterruptedException e) { e.printStackTrace(); } } public void methodB() { synchronized (this) { try { for (int i = 0; i < 5; i++) { System.out.println("methodB-" + i); Thread.sleep(1000); } } catch (InterruptedException e) { e.printStackTrace(); } } } public void methodC() { Object obj = new Object(); synchronized (obj) { try { for (int i = 0; i < 5; i++) { System.out.println("methodC-" + i); Thread.sleep(1000); } } catch (InterruptedException e) { e.printStackTrace(); } } } public static void main(String[] args) { SynchronizedTest3 test3 = new SynchronizedTest3(); Thread thread1 = new Thread(new Runnable() { @Override public void run() { test3.methodA(); } }); thread1.start(); Thread thread2 = new Thread(new Runnable() { @Override public void run() { test3.methodB(); } }); thread2.start(); Thread thread3 = new Thread(new Runnable() { @Override public void run() { test3.methodC(); } }); thread3.start(); } } 运行结果: methodA-0 methodC-0 methodA-1 methodC-1 methodA-2 methodC-2 methodA-3 methodC-3 methodA-4 methodC-4 methodB-0 methodB-1 methodB-2 methodB-3 methodB-4
/** * @author admin * @date 2018/1/12 10:48 * 作用在同一个类上讨论,每一个类只有一个类锁 * synchronized类锁 * static synchronized 和 synchronized(SynchronizedTest4.class),都是作用在同一个类锁上,所以会同步 */ public class SynchronizedTest4 { public synchronized static void methodA() { try { for (int i = 0; i < 5; i++) { System.out.println("methodA-" + i); Thread.sleep(1000); } } catch (InterruptedException e) { e.printStackTrace(); } } public void methodB() { synchronized (SynchronizedTest4.class) { try { for (int i = 0; i < 5; i++) { System.out.println("methodB-" + i); Thread.sleep(1000); } } catch (InterruptedException e) { e.printStackTrace(); } } } public static void main(String[] args) { SynchronizedTest4 test4 = new SynchronizedTest4(); Thread thread1 = new Thread(new Runnable() { @Override public void run() { test4.methodA(); } }); thread1.start(); Thread thread2 = new Thread(new Runnable() { @Override public void run() { test4.methodB(); } }); thread2.start(); } } 运行结果: methodA-0 methodA-1 methodA-2 methodA-3 methodA-4 methodB-0 methodB-1 methodB-2 methodB-3 methodB-4
/** * @author admin * @date 2018/1/12 11:03 * synchronized的对象锁和static synchronized的类锁,是两个不同的锁,所以不会同步 * 两个线程,一个调用对象锁,一个调用类锁 */ public class SynchronizedTest5 { public synchronized void methodA() { try { for (int i = 0; i < 5; i++) { System.out.println("methodA-" + i); Thread.sleep(1000); } } catch (InterruptedException e) { e.printStackTrace(); } } public synchronized static void methodB() { try { for (int i = 0; i < 5; i++) { System.out.println("methodB-" + i); Thread.sleep(1000); } } catch (InterruptedException e) { e.printStackTrace(); } } public static void main(String[] args) { SynchronizedTest5 test5 = new SynchronizedTest5(); Thread thread1 = new Thread(new Runnable() { @Override public void run() { test5.methodA(); } }); thread1.start(); Thread thread2 = new Thread(new Runnable() { @Override public void run() { test5.methodB(); } }); thread2.start(); } } 运行结果: methodA-0 methodB-0 methodA-1 methodB-1 methodB-2 methodA-2 methodB-3 methodA-3 methodB-4 methodA-4