public class PersonService {
private Person person;
private int count=0;
public PersonService() {
}
public PersonService(Person person) {
this.person = person;
}
/**
* 同步方法锁定的是当前对象，等同同步代码块 synchronized(this){}
*/
public synchronized void testMethod() {
for (int i = 0; i <10; i++) {
count++;
System.out.println(Thread.currentThread().getName()+":"+count);
}
}
/**
* PersonService.class 是Class类的实例,线程获取的对象锁是class锁，
* class锁对类的所有对象实例起到同步作用
*/
public void testClass() {
synchronized (PersonService.class) {
for (int i = 0; i <10; i++) {
count++;
System.out.println(Thread.currentThread().getName()+":"+count);
}
}
}
/**
* this表示当前运行的对象,synchronized锁定的是当前对象，
* 如果线程的this不同，则不是同一个锁，会进行异步操作而不是同步操作
*/
public void testThis() {
synchronized (this){
for (int i = 0; i < 10; i++) {
count++;
System.out.println(Thread.currentThread().getName()+":"+count);
}
}
}
/**
* 参数传递object,synchronized锁定的是object对象，如果线程获取的object对象不同，
* 则不是同一个对象锁，会进行异步操作而不是同步操作
* @param object
*/
public void testObject(Object object) {
synchronized (object) {
for (int i = 0; i <10; i++) {
count++;
System.out.println(Thread.currentThread().getName()+":"+count);
}
}
}
}
public class PersonThread extends Thread {
private PersonService personService;
public PersonThread(PersonService personService) {
this.personService = personService;
}
@Override
public void run() {
// personService.testObject(personService);//运行代码获取结果
// personService.testClass();//运行代码获取结果
personService.testThis();
}
}
public class Demo {
public static void main(String[] args) {
PersonService personService = new PersonService();
测试不是同一个对象锁的结果：测试结果1
PersonThread p1 = new PersonThread(personService);
PersonThread p2 = new PersonThread(new PersonService());
PersonThread p3 = new PersonThread(new PersonService());
PersonThread p4 = new PersonThread(new PersonService());
PersonThread p5 = new PersonThread(new PersonService());
//测试同一个对象锁的结果：测试结果2
// PersonThread p1 = new PersonThread(personService);
// PersonThread p2 = new PersonThread(personService);
// PersonThread p3 = new PersonThread(personService);
// PersonThread p4 = new PersonThread(personService);
// PersonThread p5 = new PersonThread(personService);
p1.start();
p2.start();
p3.start();
p4.start();
p5.start();
}
}
测试结果1：线程之间异步执行
Thread-2:1
Thread-1:1
Thread-2:2
Thread-1:2
Thread-2:3
Thread-2:4
Thread-1:3
Thread-1:4
Thread-1:5
Thread-1:6
Thread-1:7
Thread-2:5
Thread-1:8
Thread-3:1
Thread-0:1
Thread-1:9
Thread-2:6
Thread-1:10
Thread-0:2
Thread-0:3
Thread-0:4
Thread-0:5
Thread-3:2
Thread-0:6
Thread-4:1
Thread-2:7
Thread-4:2
Thread-0:7
Thread-3:3
Thread-0:8
Thread-4:3
Thread-2:8
Thread-2:9
Thread-2:10
Thread-4:4
Thread-4:5
Thread-4:6
Thread-4:7
Thread-4:8
Thread-4:9
Thread-4:10
Thread-0:9
Thread-0:10
Thread-3:4
Thread-3:5
Thread-3:6
Thread-3:7
Thread-3:8
Thread-3:9
Thread-3:10
测试结果2：线程之间同步执行
Thread-0:1
Thread-0:2
Thread-0:3
Thread-0:4
Thread-0:5
Thread-0:6
Thread-0:7
Thread-0:8
Thread-0:9
Thread-0:10
Thread-2:11
Thread-2:12
Thread-2:13
Thread-2:14
Thread-2:15
Thread-2:16
Thread-2:17
Thread-2:18
Thread-2:19
Thread-2:20
Thread-1:21
Thread-1:22
Thread-1:23
Thread-1:24
Thread-1:25
Thread-1:26
Thread-1:27
Thread-1:28
Thread-1:29
Thread-1:30
Thread-4:31
Thread-4:32
Thread-4:33
Thread-4:34
Thread-4:35
Thread-4:36
Thread-4:37
Thread-4:38
Thread-4:39
Thread-4:40
Thread-3:41
Thread-3:42
Thread-3:43
Thread-3:44
Thread-3:45
Thread-3:46
Thread-3:47
Thread-3:48
Thread-3:49
Thread-3:50
