多线程的锁是一个很重要的东西,使用好万事好,使用不好,事事糟糕。下面这个例子,如果你感兴趣,可以在文后留言共同探讨。
例子代码:
public class ShareBody {
public void print(int count) throws Exception {
synchronized ("123") {
System.out.println(Thread.currentThread().getName() + "开始打印");
for (int i = 1; i < count; i++) {
System.out.println(Thread.currentThread().getName() + " " + i);
}
Thread.sleep(2000);
}
}
}
public class ShareBodyB {
public void print(int count) throws Exception {
synchronized ("123") {
System.out.println(Thread.currentThread().getName() + "开始打印");
for (int i = 1; i < count; i++) {
System.out.println(Thread.currentThread().getName() + " " + i);
}
Thread.sleep(2000);
}
}
}
提示:上面两个类除了类名不同外,其它都完全一样。
public class ThreadA implements Runnable {
private ShareBody shareBody;
public ThreadA(ShareBody shareBody) {
this.shareBody = shareBody;
}
@Override
public void run() {
while (true) {
try {
this.shareBody.print(10);
} catch (Exception e) {
e.printStackTrace();
}
}
}
}
public class ThreadB implements Runnable {
private ShareBodyB shareBody;
public ThreadB(ShareBodyB shareBody) {
this.shareBody = shareBody;
}
@Override
public void run() {
while (true) {
try {
this.shareBody.print(20);
} catch (Exception e) {
e.printStackTrace();
}
}
}
}
提示:上面两个线程的代码,其成员变量是不同的,也就是说两个线程没有共享资源。
public class Main {
public static void main(String[] args) throws Exception {
ShareBody shareBody = new ShareBody();
ShareBodyB shareBodyB = new ShareBodyB();
ThreadA a = new ThreadA(shareBody);
ThreadB b = new ThreadB(shareBodyB);
new Thread(a).start();
new Thread(b).start();
}
}
提示:在主方法main中,创建了ShareBody和ShareBodyB两个对象,两个线程分别使用两个对象作为共享资源。
那么问题来了:输出的结果会是怎样的呢?两个线程会交叉输出?还是同步输出(一个线程输出完后,另外一个线程再输出)?
欢迎各位大神来讨论