本文为大家分享了java多线程的简单实现及线程池实例，供大家参考，具体内容如下
一、多线程的两种实现方式
1、继承Thread类的多线程
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/**
* 继承Thread类的多线程简单实现
*/
public class extThread extends Thread {
public void run(){
for(int i=0;i<100;i++){
System.out.println(getName()+"-"+i);
}
}
public static void main(String arg[]){
for(int i=0;i<100;i++){
System.out.println(Thread.currentThread().getName()+"-"+i);
if(i==50){
new extThread().start();
new extThread().start();
}
}
}
}
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2、实现Runnable接口的多线程
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/**
* 实现runable接口的多线程实例
*/
public class runThread implements Runnable {
public void run(){
for(int i=0;i<100;i++){
System.out.println(Thread.currentThread().getName()+"-"+i);
}
}
public static void main(String arg[]){
for(int i=0;i<100;i++){
System.out.println(Thread.currentThread().getName()+"-"+i);
if(i==50){
runThread rt = new runThread();
new Thread(rt,"新线程1").start();
new Thread(rt,"新线程2").start();
}
}
}
}
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二、线程池的简单实现
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//实现Runnable接口
class TestThread implements Runnable{
public void run() {
for(int i = 0;i < 100;i++){
System.out.println(Thread.currentThread().getName() + "i的值为：" + i);
}
}
}
public class threadPoolTest {
public static void main(String[] args) {
//创建一个具有固定线程数的线程池
ExecutorService pool = Executors.newFixedThreadPool(5);
//向线程池中提交三个线程
pool.submit(new TestThread());
pool.submit(new TestThread());
pool.submit(new TestThread());
//关闭线程池
pool.shutdown();
}
}
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三、java爬虫使用线程池实例
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/**
* 爬虫调度线程池
*/
public class threadPool {
public static HashMap<String, Spiders> statusMap = new HashMap<String, Spiders>();
// 存放爬虫，key为爬虫的id，value为爬虫的线程池
static HashMap<Integer, ThreadPoolExecutor> threadMap = new HashMap<Integer, ThreadPoolExecutor>();
//创建一个线程池
static ThreadPoolExecutor threadPool = new ThreadPoolExecutor(200, 230,80000L,
TimeUnit.SECONDS,
new ArrayBlockingQueue<Runnable>(10),
new ThreadPoolExecutor.CallerRunsPolicy());
public static void executeThread(Spiders spider) {
statusMap.put(String.valueOf(spider.getId()), spider);
// 爬虫有效
if (spider.getFlag() == 0) {
if (spider.getStatus() == 0) {
// 表示爬虫进入抓取状态
ThreadPoolExecutor detailPool = null;
if (threadMap.get(spider.getId()) == null) {
detailPool = new ThreadPoolExecutor(30, 80, 80000L,
TimeUnit.SECONDS, new ArrayBlockingQueue<Runnable>(
10),
new ThreadPoolExecutor.CallerRunsPolicy());
threadMap.put(spider.getId(), detailPool);
threadPool.execute(new threadRun(spider, threadMap));
}
}
}
}
}
//实现Runnable接口
class threadRun implements Runnable {
private HashMap<Integer, ThreadPoolExecutor> threadPoolMap;
private Spiders spider;
public threadRun(Spiders spider,
HashMap<Integer, ThreadPoolExecutor> threadPoolMap) {
this.threadPoolMap = threadPoolMap;
this.spider = spider;
}
//线程执行体
public void run() {
try {
if ("rong360".equals(spider.getWebsite())) {
new RongThread(threadPoolMap.get(spider.getId()), spider)
.startSpider();
} else if ("xxgg_sd".equals(spider.getWebsite())) {
new Spider_ShanDong(threadPoolMap.get(spider
.getId()), spider).startSpider();
} else if ("xxgg_gz".equals(spider.getWebsite())) {
new Spider_GuiZhou(threadPoolMap.get(spider
.getId()), spider).startSpider();
} else if ("sx".equals(spider.getWebsite())) {
new SpiderSX(spider).startSpider();
} else if ("baidu".equals(spider.getWebsite())) {
new SpiderBaiDu(spider).startSpider();
} else if ("11315".equals(spider.getWebsite())) {
new Spider11315ByName(spider).startSpider();
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
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以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持服务器之家。
原文链接：https://blog.csdn.net/William_hangshao/article/details/67644335