基于synchronized的对象锁，类锁以及死锁模拟

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分为对象锁和类锁

public class T {public void test1() throws Exception{     synchronized(this){ //对象锁     System.out.println(Thread.currentThread().getName()+"---test1  Doing");     Thread.currentThread().sleep(2000);     test2();     };}public synchronized void test2() throws Exception{ //同test1方法    System.out.println(Thread.currentThread().getName()+"--- test2 Doing");    Thread.currentThread().sleep(2000);    test1();}public void testclass1() throws Exception{     synchronized(T.class){//类锁     System.out.println(Thread.currentThread().getName()+"---testclass1  Doing");     Thread.currentThread().sleep(2000);          };}public static synchronized void testclass2() throws Exception{ //同testclass1方法     System.out.println(Thread.currentThread().getName()+"---testclass2  Doing");     Thread.currentThread().sleep(2000);     testclass3();}public static synchronized void testclass3() throws Exception{ //同testclass1方法     System.out.println(Thread.currentThread().getName()+"---testclass3  Doing");     Thread.currentThread().sleep(2000);     testclass2();}}

不同对象访问类锁测试：

public class clent {public static void main(String[] args) throws Exception {final CountDownLatch c=new CountDownLatch(1);new Thread(new Runnable(){@Overridepublic void run() {T t1=new T();try {System.out.println(Thread.currentThread().getName()+"启动");c.await();t1.testclass3();} catch (Exception e) {e.printStackTrace();}}}).start();   new Thread(new Runnable(){@Overridepublic void run() {T t1=new T();try {System.out.println(Thread.currentThread().getName()+"启动");c.await();t1.testclass2();} catch (Exception e) {e.printStackTrace();}}}).start();   c.countDown();   /* 可以发现 类的synchronized一个线程获得不释放，其他线程就不能访问 通过Jconsole可以看到Thread0 一直在等待Thread1   Thread-1启动   Thread-1---testclass2  Doing   Thread-0启动   Thread-1---testclass3  Doing   Thread-1---testclass2  Doing   Thread-1---testclass2  Doing   Thread-1---testclass3  Doing*/}

不同对象访问对象锁测试：

public class clent1 {public static void main(String[] args) {final CountDownLatch c=new CountDownLatch(1);new Thread(new Runnable(){@Overridepublic void run() {T t1=new T();try {System.out.println(Thread.currentThread().getName()+"启动");c.await();t1.test1();} catch (Exception e) {e.printStackTrace();}}}).start();   new Thread(new Runnable(){@Overridepublic void run() {T t1=new T();try {System.out.println(Thread.currentThread().getName()+"启动");c.await();t1.test2();} catch (Exception e) {e.printStackTrace();}}}).start();   c.countDown();  /* Thread-0启动   Thread-0---test1  Doing   Thread-1启动   Thread-1--- test2 Doing      */}

同一个对象，多个线程访问对象锁测试：

public class client2 {public static void main(String[] args) {final CountDownLatch c=new CountDownLatch(1);final T t1=new T();new Thread(new Runnable(){@Overridepublic void run() {try {System.out.println(Thread.currentThread().getName()+"启动");c.await();t1.test1();} catch (Exception e) {e.printStackTrace();}}}).start();   new Thread(new Runnable(){@Overridepublic void run() {try {System.out.println(Thread.currentThread().getName()+"启动");c.await();t1.test2();} catch (Exception e) {e.printStackTrace();}}}).start();   c.countDown();}/*结果 同一个对象，当其中一个线程没有释放锁时，另一个会一直等待。Thread-1启动Thread-1--- test2 DoingThread-0启动Thread-1---test1  DoingThread-1--- test2 DoingThread-1---test1  DoingThread-1--- test2 Doing*/}

以上演示的是阻塞等待，下面演示死锁。

public class E {public static synchronized void testclass() throws Exception{     System.out.println(Thread.currentThread().getName()+"---E.method  Doing");    Thread.currentThread().sleep(2000);    E1.testclass();}}

public class E1 {public static synchronized void testclass() throws Exception{     System.out.println(Thread.currentThread().getName()+"---E1.method  Doing");   Thread.currentThread().sleep(1000);    E.testclass();}}

public class SiSuo {public static void main(String[] args) {final CountDownLatch c=new CountDownLatch(1);new Thread(new Runnable(){@Overridepublic void run() {try {c.await();E.testclass();E1.testclass();} catch (Exception e) {// TODO Auto-generated catch blocke.printStackTrace();}}}).start();new Thread(new Runnable(){@Overridepublic void run() {try {c.await();E1.testclass();E.testclass();} catch (Exception e) {// TODO Auto-generated catch blocke.printStackTrace();}}}).start();c.countDown();}/*执行结果，一直等待Thread-1---E1.method  DoingThread-0---E.method  Doing*/}

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