基于synchronized的对象锁，类锁以及死锁模拟

矫情吗；* 2023-09-27 22:28 4阅读 0赞

**基于****synchronized****的对象锁，类锁以及死锁模拟**

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()\{

@Override

public 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()\{ @Override

public 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---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()\{

@Override

public 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()\{

@Override

public 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()\{

@Override

public 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()\{

@Override

public 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 Doing

Thread-0启动

Thread-1---test1 Doing

Thread-1--- test2 Doing

Thread-1---test1 Doing

Thread-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()\{

@Override

public void run() \{

try \{

c.await();

E.testclass();

E1.testclass();

\} catch (Exception e) \{

// TODO Auto-generated catch block

e.printStackTrace();

\}).start();

new Thread(new Runnable()\{

@Override

public void run() \{

try \{

c.await();

E1.testclass();

E.testclass();

\} catch (Exception e) \{

// TODO Auto-generated catch block

e.printStackTrace();

基于synchronized的对象锁，类锁以及死锁模拟

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