下面是一个具有同步功能的多线程示例，这是和上篇文章同样的例子，它依次打印计数器值，每次运行它时，它产生相同的结果。
实例
class PrintDemo {
public void printCount() {
try {
for(int i = 5; i > 0; i--) {
System.out.println("Counter --- " + i );
}
}catch (Exception e) {
System.out.println("Thread interrupted.");
}
}
}
class ThreadDemo extends Thread {
private Thread t;
private String threadName;
PrintDemo PD;
ThreadDemo( String name, PrintDemo pd) {
threadName = name;
PD = pd;
}
public void run() {
synchronized(PD) {
PD.printCount();
}
System.out.println("Thread " + threadName + " exiting.");
}
public void start () {
System.out.println("Starting " + threadName );
if (t == null) {
t = new Thread (this, threadName);
t.start ();
}
}
}
public class TestThread {
public static void main(String args[]) {
PrintDemo PD = new PrintDemo();
ThreadDemo T1 = new ThreadDemo( "Thread - 1 ", PD );
ThreadDemo T2 = new ThreadDemo( "Thread - 2 ", PD );
T1.start();
T2.start();
// wait for threads to end
try {
T1.join();
T2.join();
}catch( Exception e) {
System.out.println("Interrupted");
}
}
}
每次运行此程序时都会产生相同的结果 -
Starting Thread - 1
Starting Thread - 2
Counter --- 5
Counter --- 4
Counter --- 3
Counter --- 2
Counter --- 1
Thread Thread - 1 exiting.
Counter --- 5
Counter --- 4
Counter --- 3
Counter --- 2
Counter --- 1
Thread Thread - 2 exiting.
