1.描述
最近在刷面試題，看到了一個很好玩的面試題，就是使用線程技術創建3個線程，分別打印A,B,C的線程，然後按順序打印ABC，連續打印3次。我感覺這個面試題挺有意思的就花了點時間，寫了一下，下面貼出代碼，如果有地方錯誤的請大神多多指點。
public class LockDemo3 {
public static void main(String[] args) {
new LockDemo3().doMain();
}
public void doMain(){
Res res = new Res();
ThreadA threadA = new ThreadA(res);
ThreadB threadB = new ThreadB(res);
ThreadC threadC = new ThreadC(res);
threadA.start();
threadB.start();
threadC.start();
}
class Res{
private int flag = 0;
}
class ThreadA extends Thread{
private Res res;
public ThreadA(Res res) {
this.res = res;
}
@Override
public void run() {
int count = 0;
while(count < 3){
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
}
synchronized (res) {
if(res.flag != 0){
try {
res.wait();
} catch (InterruptedException e) {
}
}else{
System.out.println("A");
res.flag = 1;
++count;
}
res.notify();
}
}
}
}
class ThreadB extends Thread{
private Res res;
public ThreadB(Res res) {
this.res = res;
}
@Override
public void run() {
int count = 0;
while(count < 3){
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
}
synchronized (res) {
if(res.flag != 1){
try {
res.wait();
} catch (InterruptedException e) {
}
}else{
System.out.println("B");
res.flag = 2;
++count;
}
res.notify();
}
}
}
}
class ThreadC extends Thread{
private Res res;
public ThreadC(Res res) {
this.res = res;
}
@Override
public void run() {
int count = 0;
while(count < 3){
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
}
synchronized (res) {
if(res.flag != 2){
try {
res.wait();
} catch (InterruptedException e) {
}
}else {
System.out.println("C");
res.flag = 0;
++count;
}
res.notify();
}
}
}
}
}
我在doMain方法中創建了3個線程，分別是ThreadA,ThreadB,ThreadC,它們分別打印A,B,C；然後使用線程的wait(),notify()實現線程間的通信。你們只需將代碼拷貝，運行一下就可以了。其中的知識還得你們自己悟。