java的同步方法和同步代碼塊，對象鎖，類鎖區別

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/** * @author admin * @date 2018/1/12 9:48 * 作用在同一個執行個體對象上討論 * synchronized同步方法的測試 * 兩個線程，一個線程調用synchronized修飾方法，另一個線程可以調用非synchronized修飾的方法，互不影響 */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();    }}運行結果：methodA-0methodB-0methodA-1methodB-1methodB-2methodA-2methodA-3methodB-3methodA-4methodB-4

 

/** * @author admin * @date 2018/1/12 10:16 * 作用在同一個執行個體對象上討論 * Sychronized代碼塊的測試 * 兩個線程，一個線程執行synchronized代碼塊，另一個線程執行非synchronized代碼塊 */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();    }}運行結果：methodA-0methodB-0methodA-1methodB-1methodA-2methodB-2methodB-3methodA-3methodA-4methodB-4

 

/** * @author admin * @date 2018/1/12 10:33 * 作用在同一個執行個體對象上討論 * Synchronized同步方法和同步代碼塊 * 1、synchronized和synchronized（this）二者沒區別，都作用在this對象鎖上面，所以會同步 * 2、synchronized（obj），這個是作用在obj對象鎖上面，和this對象鎖不同，所以不會同步 */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();    }}運行結果：methodA-0methodC-0methodA-1methodC-1methodA-2methodC-2methodA-3methodC-3methodA-4methodC-4methodB-0methodB-1methodB-2methodB-3methodB-4

 

/** * @author admin * @date 2018/1/12 10:48 * 作用在同一個類上討論，每一個類只有一個類鎖 * synchronized類鎖 * static synchronized 和 synchronized（SynchronizedTest4.class）,都是作用在同一個類鎖上，所以會同步 */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();    }}運行結果：methodA-0methodA-1methodA-2methodA-3methodA-4methodB-0methodB-1methodB-2methodB-3methodB-4

 

/** * @author admin * @date 2018/1/12 11:03 * synchronized的對象鎖和static synchronized的類鎖，是兩個不同的鎖，所以不會同步 * 兩個線程，一個調用對象鎖，一個調用類鎖 */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();    }}運行結果：methodA-0methodB-0methodA-1methodB-1methodB-2methodA-2methodB-3methodA-3methodB-4methodA-4

 

java的同步方法和同步代碼塊，對象鎖，類鎖區別