多线程的理解与使用介绍
①process进程 ②current当前的③thread线程④runnable可获取的
⑤interrupt中断⑥join加入⑦yield产生⑧synchronize同时发生
二.预习部分
1.线程与进程的区别:
进程是系统运行程序的基本单位
线程是进程中执行运算的最小单位
2.说明创建线程的方式有哪两种
①继承thread类
②实现Runnable接口
3.线程的生命周期可分为几个阶段,各是什么阶段
五个阶段:①创建②就绪③运行④阻塞⑤死亡
4.使用线程的什么方法可以设置线程的休眠,线程的强制执行,线程的礼让
分别为:sleep(),join(),yield()
5.什么情况下需要进行线程的同步,线程的同步有几种方式
当访问冲突时需要进行
两种方式:①同步方法②同步代码块
三.练习部分
1.使用继承Thread类的方法创建线程,显示相应内容
首先创建一个线程类:
package oneOne;
public class MyRunnableone extends Thread{
public void run() {
for(int i=1;i<=20;i++){
System.out.println(i+".你好,来自线程"+Thread.currentThread().getName());
}
}
}
再创建main方法类去掉用就行了
package oneOne;
public class testone {
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
MyRunnableone my=new MyRunnableone();
MyRunnableone my1=new MyRunnableone();
my.start();
my1.start();
}
}
2.使用实现Runnable接口方式创建线程
同第一个先创建实现类:
package oneTwo;
public class MyRunnabletwo implements Runnable{
public void run() {
for(int i=1;i<=20;i++){
System.out.println(i+".你好,来自线程"+Thread.currentThread().getName());
}
}
}
再main方法:
package oneTwo;
public class testtwo {
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
MyRunnabletwo my=new MyRunnabletwo();
MyRunnabletwo my1=new MyRunnabletwo();
Thread tr=new Thread(my);
Thread tr1=new Thread(my1);
tr.start();
tr1.start();
}
}
3.使用多线程模拟多人徒步爬山
先创建继承或者实现类(我这里用了继承):
package oneThree;
public class MyRunnablethree extends Thread{
private int time;
public int num=0;
public MyRunnablethree(String name,int time,int kio) {
super(name);
this.time=time;
this.num=kio*1000/100;
}
public void run() {
while (num>0) {
try {
Thread.sleep(this.time);
} catch (InterruptedException e) {
// TODO: handle exception
e.printStackTrace();
}
System.out.println(Thread.currentThread().getName()+"爬完100米!");
num--;
}
System.out.println(Thread.currentThread().getName()+"到达终点!");
}
}
再main方法:
package oneThree;
public class testthree {
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
MyRunnablethree young=new MyRunnablethree("年轻人", 500, 1);
MyRunnablethree old=new MyRunnablethree("老年人", 1500, 1);
MyRunnablethree child=new MyRunnablethree("小孩", 600, 1);
System.out.println("**********开始爬山*********");
old.start();
young.start();
child.start();
}
}
4.显示,设置线程优先级
先继承或者实现类:
package oneFour;
public class MyRunnablefour extends Thread{
public void run() {
Thread.currentThread().setPriority(1);
System.out.println("子线程名:"+Thread.currentThread().getName()+",优先级:"+Thread.currentThread().getPriority());
}
}
再main:
package oneFour;
public class testfour {
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
MyRunnablefour myf=new MyRunnablefour();
myf.start();
System.out.println("*************显示默认优先级********");
System.out.println("主线程名:"+Thread.currentThread().getName()+",优先级:"+Thread.currentThread().getPriority());
Thread.currentThread().setPriority(10);
System.out.println("***********修改默认优先级后***********");
//myf.setPriority(1);
System.out.println("主线程名:"+Thread.currentThread().getName()+",优先级:"+Thread.currentThread().getPriority());
//System.out.println("子线程名:"+MyRunnablefour.currentThread().getName()+",优先级:"+MyRunnablefour.currentThread().getPriority());
}
}
5.模拟叫号看病
先继承或实现类:
package oneFive;
public class MyRunnablefive extends Thread{
private int time;
//public int pertail=0;
public MyRunnablefive(String common,int time) {
super(common);
this.time=time;
}
public void run() {
Thread.currentThread().setPriority(8);
for(int i=1;i<=10;i++){
try {
Thread.sleep(this.time);
} catch (InterruptedException e) {
// TODO: handle exception
e.printStackTrace();
}
System.out.println("特需号:"+i+"号病人在看病!");
}
}
}
再main:
package oneFive;
public class testfive {
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
//MyRunnablefive pertail=new MyRunnablefive("特需号", 1000);
Thread temp=new Thread(new MyRunnablefive("特需号", 400));
temp.start();
Thread.currentThread().setPriority(4);
for(int i=1;i<=50;i++){
if(i==11){
try {
temp.join();
} catch (InterruptedException e) {
// TODO: handle exception
e.printStackTrace();
}
}
try {
Thread.sleep(200);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
System.out.println("普通号:"+i+"号病人在看病");
}
}
}
6.多线程模拟 接力赛跑
先创建继承或者实现类:
package oneSix;
public class runSix implements Runnable{
private int meters=1000;
public runSix(){
}
@Override
public void run() {
// TODO Auto-generated method stub
//System.out.println("进来了");
while (true) {
//type type = (type) true.nextElement();
synchronized (this) {
if(meters<=100){
break;
}
System.out.println(Thread.currentThread().getName()+"拿到了接力棒!");
for (int i = 0; i < 100; i+=10) {
try {
Thread.sleep(100);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
System.out.println(Thread.currentThread().getName()+"跑了"+(i+10)+"米!");
}
meters-=100;
}
}
}
}
再main接口类:
package oneSix;
public class testsix {
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
runSix ru=new runSix();
for (int i = 0; i < 5; i++) {
new Thread(ru,(i+1)+"号选手").start();
}
}
}
7.多线程模拟网络购票
桃跑跑,张票票,黄牛党,共同抢十张票,限制黄牛党只能抢一次票
先创建继承或者实现类:
package oneSeven;
public class siteSeven implements Runnable{
private int count=10;
private int num=0;
private boolean flag=false;
@Override
public void run() {
// TODO Auto-generated method stub
//System.out.println("进来了");
while (!flag) {
synchronized (this){
//System.out.println("进来了");
if(count<=0){
flag=true;
return;
}
num++;
count--;
try {
Thread.sleep(500);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
String name=Thread.currentThread().getName();
if(name.equals("黄牛党")){
System.out.println(name+"抢到第"+num+"张票,剩余"+count+"张票!");
break;
}
System.out.println(name+"抢到第"+num+"张票,剩余"+count+"张票!");
}
}
}
}
再创建main接口类:
package oneSeven;
public class testseven {
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
siteSeven si=new siteSeven();
Thread per1=new Thread(si,"大东");
Thread yellow=new Thread(si,"黄牛党");
Thread per2=new Thread(si,"启圳");
per1.start();
yellow.start();
per2.start();
}
}
四:总结:
1.Thread类中的方法实现对线程对象的操作
①调整线程的优先级
②线程睡眠sleep()
③线程的强制运行join()
④线程礼让yield()
2.多线程允许程序员编写可最大利用CPU的高效程序
3.两种方式创建线程:
①声明一个继承了Thread类的子类并实现Thread类的run()方法
②声明一个实现Runnable接口的类,然后实现run()方法
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