多线程唤醒问题
public class FlagWork {
public static void main(String[] args) {
final Business1 b1 = new Business1();
new Thread(new Runnable() {
@Override
public void run() {
b1.a();
}
}).start();
new Thread(new Runnable() {
@Override
public void run() {
b1.b();
}
}).start();
new Thread(new Runnable() {
@Override
public void run() {
b1.c();
}
}).start();
}
}
class Business1 {
private int flag = 1;
public void a() {
for (int i = 0; i < 50; i++) {
synchronized (this) {
while (flag != 1) {
try {
this.wait();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
for (int j = 1; j <= 10; j++) {
System.out.println("线程a运行" + j + "次");
}
flag = 2;
this.notify();
}
}
}
public void b() {
for (int i = 0; i < 50; i++) {
synchronized (this) {
while (flag != 2) {
try {
this.wait();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
for (int j = 1; j <= 20; j++) {
System.out.println("线程b运行" + j + "次");
}
flag = 3;
this.notify();
}
}
}
public void c() {
for (int i = 0; i < 50; i++) {
synchronized(this){
while(flag!=3){
try {
this.wait();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
for (int j = 1; j <= 30; j++) {
System.out.println("线程c运行"+j+"次");
}
flag = 1;
this.notifyAll();
}
}
}
}A线程先运行10次，然后B线程运行20次，然后C线程运行30次，如此反复50次的代码，为什么次c方法里要用this.notifyAll，而用this.notify就不行
