第一种：package com.ucmed.zsyy.util;
/**
* Created by ucmed on 2017/2/8.
*/
public class DirtyRead {
private String username = "zjkj";
private String password = "123";
public
synchronized void setValue(String username, String password) {
System.out.println("set线程：" + Thread.currentThread().getPriority());
this.username = username;
try {
Thread.sleep(2000);
} catch(InterruptedException e) {
e.printStackTrace();
}
this.password = password;
System.out.println("setValue最终结果：username = " + username + " , password = " + password);
}
public void getValue() {
System.out.println("get线程：" + Thread.currentThread().getPriority());
System.out.println("getValue最终结果：username = " + username + " , password = " + password);
}
public static void main(String[] args) throws InterruptedException {
final DirtyRead dr = new DirtyRead();
Thread t1 = new Thread(new Runnable() {
@Override
public void run() {
dr.setValue("z3", "456");
}
});
System.out.println("主线程：" + Thread.currentThread().getPriority());
t1.start();
Thread.sleep(1000);
dr.getValue();
}
}
第二种:
package com.ucmed.zsyy.util;
/**
* Created by ucmed on 2017/2/8.
*/
public class DirtyRead {
private String username = "zjkj";
private String password = "123";
public
synchronized void setValue(String username, String password) {
System.out.println("set线程：" + Thread.currentThread().getPriority());
this.username = username;
try {
Thread.sleep(2000);
} catch(InterruptedException e) {
e.printStackTrace();
}
this.password = password;
System.out.println("setValue最终结果：username = " + username + " , password = " + password);
}
public
synchronized void getValue() {
System.out.println("get线程：" + Thread.currentThread().getPriority());
System.out.println("getValue最终结果：username = " + username + " , password = " + password);
}
public static void main(String[] args) throws InterruptedException {
final DirtyRead dr = new DirtyRead();
Thread t1 = new Thread(new Runnable() {
@Override
public void run() {
dr.setValue("z3", "456");
}
});
System.out.println("主线程：" + Thread.currentThread().getPriority());
t1.start();
Thread.sleep(1000);
dr.getValue();
}
}
理解：
这里只有一个对象，一个对象的多个synchronized修饰的方法的情况
上面例子是当get方法加上锁后，要等待set方法执行完后再执行
在方法上加synchronized关键字，持有的锁为当前对象，当一个线程调用了其中一个synchronized的方法后，其他线程再调用该类中其他synchronized修饰的方法会挂起等待，需要等上一个线程执行完，释放锁后，其他调用线程取得锁后才会执行
不是多个锁，是多个synchronized修饰的方法..这些方法是同一个锁