多线程----线程通信

线程通信方法

Java实现线程通信的方法

wait()方法

挂起当前线程，并释放共享资源的锁

notify()方法

在因调用该对象的wait()方法而阻塞的线程中随机选择一个解除阻塞，但要等到获得锁后才可真正执行

notifyAll()方法

将因调用该对象的wait()方法而阻塞的所有线程一次性全部解除阻塞

案例1--存钱取钱

需求：对前面存钱、取钱案例进行线程通信，保证存一笔，取一笔，不存 就不能取。

package com.qf.day22_1;
public class Demo2 {
public static void main(String[] args) {
bankCard card = new bankCard();
addMoney add = new addMoney(card);
subMoney sub = new subMoney(card);

Thread zhangsan = new Thread(add,"张三");
Thread lisi = new Thread(add,"李四");
Thread xiaoming = new Thread(sub,"小明");
Thread xiaohong = new Thread(sub,"小红");

zhangsan.start();
lisi.start();
xiaohong.start();
xiaoming.start();

}
}
/**
* 银行卡
* @author Administrator
*
*/
class bankCard{
double money;
boolean flage=false;//false 为没钱，true为有钱
/**
* 存钱
* @param d
*/
public synchronized void SaveMoey(double d) {

while (flage) {
try {
this.wait();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

}
money=money+d;
System.out.println(Thread.currentThread().getName()+"存了"+d+",卡上余额"+money);

flage = true;
this.notifyAll();
}
/**
* 取钱
* @param d
* @return
*/
public synchronized void recMoney(double d) {
while (!flage) {
try {
this.wait();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}

if (money>=d) {
money = money-d;
System.out.println(Thread.currentThread().getName()+"取了"+d+",卡上余额"+money);

}else {
System.out.println("余额不足");

}
flage = false;
this.notifyAll();
}
}

/**
* 存钱类
* @author Administrator
*
*/
class addMoney implements Runnable{
bankCard card;
public addMoney(bankCard card) {
// TODO Auto-generated constructor stub
this.card = card;
}
@Override
public void run() {
// TODO Auto-generated method stub
for (int i = 0; i < 10; i++) {
//			synchronized (card) {
//				this.card.money += 1000;
//				System.out.println(Thread.currentThread().getName()
//						+ "存了1000,卡上余额" + this.card.money);
//			}
this.card.SaveMoey(1000);
}
}

}
/**
* 取钱类
* @author Administrator
*
*/
class subMoney implements Runnable{

bankCard card;
public subMoney(bankCard card) {
// TODO Auto-generated constructor stub
this.card = card;
}
@Override
public void run() {
// TODO Auto-generated method stub
for (int i = 0; i < 10; i++) {
//			synchronized (card) {
//				if (this.card.money >= 1000) {
//
//					this.card.money -= 1000;
//					System.out.println(Thread.currentThread().getName()
//							+ "取了1000，卡上余额" + this.card.money);
//				} else {
//					System.out.println("余额不足");
//					i--;
//				}

this.card.recMoney(1000);

}
}

}

案例2--输入输出字母

需求：按照26个字母表顺序，依次 输入一个字母，输出一个字母。

package com.qf.day22_1;

public class Demo3 {
public static void main(String[] args) {
LetterCon letterCon = new LetterCon();
InputThread in = new InputThread(letterCon);
OutputThread out = new OutputThread(letterCon);
Thread in1 = new Thread(in,"线程1");
Thread out1 = new Thread(out,"线程2");
Thread in2 = new Thread(in,"线程3");
Thread out2 = new Thread(out,"线程4");
in1.start();
in2.start();
out1.start();
out2.start();
}
}

class LetterCon{
char let;
boolean flage=false;//true 为 有数据，false  为无数据

public synchronized void input(char c) {

while (flage) {
try {
this.wait();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}

System.out.println(Thread.currentThread().getName()+"输入"+c);
let = c;

flage = true;
this.notifyAll();

}
public synchronized void output(){
while (!flage) {
try {
this.wait();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
System.out.println(Thread.currentThread().getName()+"输出"+let);

flage = false;
this.notifyAll();
}
}

class InputThread implements Runnable{
private LetterCon letterCon ;
public InputThread(LetterCon letterCon){
this.letterCon = letterCon;
}
@Override
public void run() {
// TODO Auto-generated method stub
for (char i = 'A'; i <='Z'; i++) {
letterCon.input(i);
}
}

}

class OutputThread implements Runnable{
private LetterCon letterCon;
public OutputThread(LetterCon letterCon){
this.letterCon=letterCon;
}
@Override
public void run() {
// TODO Auto-generated method stub
for (int i = 0; i < 26; i++) {
letterCon.output();
}
}

}

案例三----生产者消费者问题

需求

生产者可以生产面包 ，面包放入一个容器中，容器大小为6，消费者可以从容器中消费，如果没有面包是不能消费的，要通知生产者生产，如果容器中已经满了，也不能再生产，要通知消费者去消费。

package com.qf.day22_1;

public class Product_ConsumeDemo {
public static void main(String[] args) {
BreadCon breadCon = new BreadCon();
ProductThread p = new ProductThread(breadCon);
ConsumThread c = new ConsumThread(breadCon);

Thread zhangsan = new Thread(p,"张三");
Thread lisi = new Thread(p,"李四");
Thread xiaoming = new Thread(c, "小明");
Thread xiaohong = new Thread(c, "小红");
zhangsan.start();
lisi.start();
xiaoming.start();
xiaohong.start();

}

}

class Bread{
private String Pro_name;
private int bread_Id;
public String getPro_name() {
return Pro_name;
}
public void setPro_name(String pro_name) {
Pro_name = pro_name;
}
public int getBread_Id() {
return bread_Id;
}
public void setBread_Id(int bread_Id) {
this.bread_Id = bread_Id;
}
public Bread(String pro_name, int bread_Id) {
super();
Pro_name = pro_name;
this.bread_Id = bread_Id;
}

}

class BreadCon{
Bread[] breads = new Bread[6];
int length = -1;
//生产方法
public synchronized void product(Bread bread){
while(length>=5){
try {
this.wait();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}

length++;
breads[length]=bread;
System.out.println(Thread.currentThread().getName()+"生产了"+bread.getBread_Id()+"面包");

this.notifyAll();

}

//消费方法
public synchronized void consum() {

while(length<=-1){
try {
this.wait();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}

Bread b = breads[length];
length--;
System.out.println(Thread.currentThread().getName()+"消费了"+b.getBread_Id()+"面包 ");
this.notifyAll();
}

}

class ProductThread implements Runnable{
BreadCon breadCon;
public ProductThread(BreadCon breadCon){
this.breadCon = breadCon;
}
@Override
public void run() {
// TODO Auto-generated method stub
for (int i = 0; i < 30; i++) {
Bread bread = new Bread(Thread.currentThread().getName(), i);
breadCon.product(bread);
}
}

}

class ConsumThread implements Runnable{
BreadCon breadCon;
public ConsumThread(BreadCon breadCon){
this.breadCon = breadCon;
}
@Override
public void run() {
// TODO Auto-generated method stub
for (int i = 0; i < 30; i++) {
breadCon.consum();
}
}

}