Synchroniz用法

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1.同一个类的synchronized 锁住的方法，同一时间不能有多个线程同时访问

package com.mercurylake.test.tree;import java.util.HashSet;import java.util.Set;import org.apache.commons.lang.StringUtils;import com.sun.swing.internal.plaf.synth.resources.synth;public class A  {public static void main(String[] args) {A x=new A();Runnable r1=new B(x,0);Runnable r2=new B(x,1);Thread t1=new Thread(r1);Thread t2=new Thread(r2);t1.start();t2.start();}public synchronized void  a1(){System.out.println("a1..begin");try {Thread.sleep(10000);} catch (InterruptedException e) {// TODO Auto-generated catch blocke.printStackTrace();}System.out.println("a1..end");}public synchronized void  b1(){System.out.println("b1");}}class B implements Runnable{private A a;private int mark;public B(A a, int mark) {super();this.a = a;this.mark = mark;}@Overridepublic void run() {// TODO Auto-generated method stubif(mark==0){a.a1();}else a.b1();}}

返回值：a1..begin ；a1..end ；b1

2.synchronized（this）代码块与 public synchronized void a() 效果相同

package com.mercurylake.test.tree;import java.util.HashSet;import java.util.Set;import org.apache.commons.lang.StringUtils;import com.sun.swing.internal.plaf.synth.resources.synth;public class A  {public static void main(String[] args) {A x=new A();Runnable r1=new B(x,0);Runnable r2=new B(x,1);Thread t1=new Thread(r1);Thread t2=new Thread(r2);t1.start();try {Thread.sleep(1000);} catch (InterruptedException e) {// TODO Auto-generated catch blocke.printStackTrace();}t2.start();}public synchronized void  a1(){System.out.println("a1..begin");try {Thread.sleep(10000);} catch (InterruptedException e) {// TODO Auto-generated catch blocke.printStackTrace();}System.out.println("a1..end");}public  void  b1(){synchronized (this) {System.out.println("b1");}}}class B implements Runnable{private A a;private int mark;public B(A a, int mark) {super();this.a = a;this.mark = mark;}@Overridepublic void run() {// TODO Auto-generated method stubif(mark==0){a.a1();}else a.b1();}}

输出值与例1中相同

3.synchronized static 用法：锁的不再是实例，而是Class，同一个Class 都会受到同步约束

package com.mercurylake.test.tree;import java.util.HashSet;import java.util.Set;import org.apache.commons.lang.StringUtils;import com.sun.swing.internal.plaf.synth.resources.synth;public class A  {public static void main(String[] args) {A x=new A();A y=new A();Runnable r1=new B(x,0);Runnable r2=new B(y,1);Thread t1=new Thread(r1);Thread t2=new Thread(r2);t1.start();try {Thread.sleep(1000);} catch (InterruptedException e) {// TODO Auto-generated catch blocke.printStackTrace();}t2.start();}public synchronized static void  a1(){System.out.println("a1..begin");try {Thread.sleep(10000);} catch (InterruptedException e) {// TODO Auto-generated catch blocke.printStackTrace();}System.out.println("a1..end");}public synchronized  static void  b1(){System.out.println("b1");}}class B implements Runnable{private A a;private int mark;public B(A a, int mark) {super();this.a = a;this.mark = mark;}@Overridepublic void run() {// TODO Auto-generated method stubif(mark==0){a.a1();}else a.b1();}}

返回值与例1相同

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