问题：
ABC三个线程交替打印10遍，要求A打印5次，B打印10次，C打印15次，
第一遍
AAAAABBBBBBBBBBCCCCCCCCCCCCCCC
第二遍
AAAAABBBBBBBBBBCCCCCCCCCCCCCCC
...共打印10遍
1.使用Sychronized+wait()+notify()的方式
package com.yang.test;
/**
* ABC三个线程交替打印10遍，要求A打印5次，B打印10次，C打印15次
* 第一遍
* AAAAABBBBBBBBBBCCCCCCCCCCCCCCC
* 第二遍
* AAAAABBBBBBBBBBCCCCCCCCCCCCCCC
* ...共打印10遍
* @author yang yajun
* @date 2020/12/2615:31
*/
public class OrderThreadPrint {
public static void main(String[] arg0){
Print print = new Print();
new Thread(()->{
for (int i = 0; i < 10; i++) {
print.printA();
}
},"A").start();
new Thread(()->{
for (int i = 0; i < 10; i++) {
print.printB();
}
},"B").start();
new Thread(()->{
for (int i = 0; i < 10; i++) {
print.printC();
}
},"C").start();
}
}
class Print{
private int i = 1;
public synchronized void printA(){
while (i%3!=1) {
try {
wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
for (int j = 0; j < 5; j++) {
System.out.print(Thread.currentThread().getName() + i);
}
i++;
notifyAll();
}
public synchronized void printB(){
while (i%3!=2) {
try {
wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
for (int j = 0; j < 10; j++) {
System.out.print(Thread.currentThread().getName()+i);
}
i++;
notifyAll();
}
public synchronized void printC(){
while (i%3!=0) {
try {
wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
for (int j = 0; j < 15; j++) {
System.out.print(Thread.currentThread().getName() + i);
}
i++;
notifyAll();
}
}
2.使用Lock(Condition)+await()+signal()来实现
package com.yang.test;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
/**
* ABC三个线程交替打印10遍，要求A打印5次，B打印10次，C打印15次
* 第一遍
* AAAAABBBBBBBBBBCCCCCCCCCCCCCCC
* 第二遍
* AAAAABBBBBBBBBBCCCCCCCCCCCCCCC
* ...共打印10遍
* @author yang yajun
* @date 2020/12/2615:31
*/
public class OrderThreadPrintLock {
public static void main(String[] arg0){
PrintLk print = new PrintLk();
new Thread(()->{
for (int i = 0; i < 10; i++) {
print.printA();
}
},"A").start();
new Thread(()->{
for (int i = 0; i < 10; i++) {
print.printB();
}
},"B").start();
new Thread(()->{
for (int i = 0; i < 10; i++) {
print.printC();
}
},"C").start();
}
}
class Print{
private int i = 1;
private Lock lock = new ReentrantLock();
private Condition condition1 = lock.newCondition();
private Condition condition2 = lock.newCondition();
private Condition condition3 = lock.newCondition();
public synchronized void printA(){
lock.lock();
try {
while (i!=1) {//判断，多线程通信，使用while代替if
try {
condition1.await();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
//干活
for (int j = 0; j < 5; j++) {
System.out.print(Thread.currentThread().getName() + i);
}
i=2;
condition2.signal();//通知
}finally {
lock.unlock();
}
}
public synchronized void printB(){
lock.lock();
try {
while (i!=2) {
try {
condition2.await();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
for (int j = 0; j < 10; j++) {
System.out.print(Thread.currentThread().getName()+i);
}
i=3;
condition3.signal();
}finally {
lock.unlock();
}
}
public synchronized void printC(){
lock.lock();
try {
while (i!=3) {
try {
condition3.await();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
for (int j = 0; j < 15; j++) {
System.out.print(Thread.currentThread().getName() + i);
}
i=1;
condition1.signal();
}finally {
lock.unlock();
}
}
}
总结：使用Synchronized和Lock都能实现，而Lock的优势是可以精准唤醒，不像Synchronized的只能notifyAll()