java Callable使用实例

多个线程实现累加

package com.thread;import java.util.concurrent.Callable;import java.util.concurrent.ExecutionException;import java.util.concurrent.ExecutorService;import java.util.concurrent.Executors;import java.util.concurrent.Future;/** * @author:xxx * @TODO:使用callable进行自增 */public class AddCallable {public static void main(String[] args) {long begin = System.currentTimeMillis();ExecutorService threadPool = Executors.newCachedThreadPool();AddTask task01 = new AddTask("Task-01", 1, 50);AddTask task02 = new AddTask("Task-02", 51, 100);//得到的结果集Future<Long> resultSet01 = threadPool.submit(task01);Future<Long> resultSet02 = threadPool.submit(task02);try {System.out.println("最后的结果是："+(resultSet01.get()+resultSet02.get()));} catch (InterruptedException e) {e.printStackTrace();} catch (ExecutionException e) {e.printStackTrace();}finally{threadPool.shutdown();}System.out.println(System.currentTimeMillis() - begin);}};/** * @author:xxx * @TODO:泛型中的Long表示返回的类型 */class AddTask implements Callable<Long> {private String name;private long begin;private long end;public AddTask(String name, long begin, long end) {this.name = name;this.begin = begin;this.end = end;}@Overridepublic Long call() throws Exception {System.out.println(Thread.currentThread().getName());System.out.println(name + " 执行中.......");long sum = 0;for (long i = begin; i <= end; i++) {sum += i;}return sum;}};

例子 2

/** *  */package com.comtop.test;import java.util.ArrayList;import java.util.List;import java.util.concurrent.ArrayBlockingQueue;import java.util.concurrent.Callable;import java.util.concurrent.ExecutionException;import java.util.concurrent.ThreadPoolExecutor;import java.util.concurrent.TimeUnit;/** * @ProjectName:Skeleton * @PackageName:com.comtop.test * @Verson :0.1 * @CreateUser :lanweixing * @CreateDate :2014-9-3上午9:41:16 * @UseFor : */public class DoThread {public static void main(String[] args) {List<Num> list = new ArrayList<Num>();List<Message> result1 = new ArrayList<Message>();List<Message> result = new ArrayList<Message>();// ExecutorService pool = Executors.newCachedThreadPool() ;//使用线程池处理ThreadPoolExecutor pool = new ThreadPoolExecutor(3, 4, 3000L,TimeUnit.MILLISECONDS, new ArrayBlockingQueue<Runnable>(2));for (int i = 0; i < 1000000; i++) {list.add(new Num(i));}long begin = System.currentTimeMillis();try {//1000000条数据5个线程跑   每个线程跑集合中的一部分for (int i = 0; i < 5; i++) {result1 = pool.submit(new Main4Thread(list, i * 200000, (i + 1) * 200000)).get();result.addAll(result1);}} catch (InterruptedException e) {e.printStackTrace();} catch (ExecutionException e) {e.printStackTrace();}pool.shutdown();System.out.println("所用时间" + (System.currentTimeMillis() - begin));System.out.println(result.size());}};class Main4Thread implements Callable<List<Message>> {private List<Num> num;private int begin;private int end;/** * @param num */Main4Thread(List<Num> num, int begin, int end) {super();this.num = num;this.begin = begin;this.end = end;}@Overridepublic List<Message> call() throws Exception {List<Message> msgList = new ArrayList<Message>();for (int i = begin; i < end; i++) {if (num.get(i).getAge() >= 500000) {//线程逻辑处理Message msg = new Message();msg.setMsg(num.get(i).getAge() + " Too old");msgList.add(msg);}}System.out.println(Thread.currentThread().getName());return msgList;}};class Message {private String msg;public String getMsg() {return msg;}public void setMsg(String msg) {this.msg = msg;}};class Num {private int age;/** * @param age */Num(int age) {super();this.age = age;}public int getAge() {return age;}public void setAge(int age) {this.age = age;}};

3.使用线程处理项目中的需求

需求：三个线程并行处理三个SQL语句查询

线程类

@Scope("prototype")//线程类需要注解到spring中 不然无法使用具体DAO操作@Servicepublic class MainExcutor implements Callable<List<XXXVO>> {// 日志记录private final static Logger logger = LoggerFactory.getLogger(MainExcutor.class);@Resourceprivate XXXDAO xxxDAO;private XXXVO xxxVO;public XXXVO getXXXVO() {return xxxVO;}public void setXXXVO(XXXVO xxxVO) {this.xxxVO = xxxVO;}MainExcutor() {super();}@Overridepublic List<XXXVO> call() throws Exception {logger.info(" 线程查询数据中。。。");List<XXXVO> resultList = new ArrayList<XXXVO>();resultList = this.xxxDAO.queryXXXData(xxxVO);logger.info(" 线程查询数据结束。。。");return resultList;}};

XXXDAO代码片段

 //三个线程实例 @Resourceprivate MainExcutor mainExcutor1;@Resourceprivate MainExcutor mainExcutor2;@Resourceprivate MainExcutor mainExcutor3; Map<String, Callable<List<XXXVO>>> taskMap = new HashMap<String, Callable<List<XXXVO>>>();// 三个参数对象各不相同BeanCopier beanCopier = BeanCopier.create(XXXVO.class,XXXVO.class, false);XXXVO xxxVO02 = new XXXVO();XXXVO xxxVO03 = new ElectricTopicVO();beanCopier.copy(xxxVO, xxxVO02, null);beanCopier.copy(xxxVO, xxxVO03 , null);// 1   2  3 xxxVO.setType("1");this.mainExcutor1.setXXXVO(xxxVO);taskMap.put("Task1", this.mainExcutor1);xxxVO02.setType("2");this.mainExcutor2.setXXXVO(xxxVO02);taskMap.put("Task2", this.mainExcutor2);xxxVO03 .setType("3");this.mainExcutor3.setXXXVO(xxxVO03);taskMap.put("Task3", this.mainExcutor3);MessageThreadPoolExecutor executor = new MessageThreadPoolExecutor(3,4, 3000L, TimeUnit.MILLISECONDS,new ArrayBlockingQueue<Runnable>(4));try {Map<String, List<XXXVO>> resultMap = executor.performTasks(taskMap);for (String key : resultMap.keySet()) {tempList = resultMap.get(key);resultList.addAll(tempList);}} catch (InterruptedException e1) {e1.printStackTrace();}

线程池实现类（实现并发执行的关键）

class MessageThreadPoolExecutor extends ThreadPoolExecutor {// 把父类的构造函数全弄出来算了。。。public MessageThreadPoolExecutor(int corePoolSize, int maximumPoolSize,long keepAliveTime, TimeUnit unit,BlockingQueue<Runnable> workQueue, RejectedExecutionHandler handler) {super(corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue,handler);}public MessageThreadPoolExecutor(int corePoolSize, int maximumPoolSize,long keepAliveTime, TimeUnit unit,BlockingQueue<Runnable> workQueue, ThreadFactory threadFactory) {super(corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue,threadFactory);}public MessageThreadPoolExecutor(int corePoolSize, int maximumPoolSize,long keepAliveTime, TimeUnit unit, BlockingQueue<Runnable> workQueue) {super(corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue);}public MessageThreadPoolExecutor(int corePoolSize, int maximumPoolSize,long keepAliveTime, TimeUnit unit,BlockingQueue<Runnable> workQueue, ThreadFactory threadFactory,RejectedExecutionHandler handler) {super(corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue,threadFactory, handler);}// 线程池主要执行方法public <T> Map<String, T> performTasks(Map<String, Callable<T>> taskMap)throws InterruptedException {// 无任务集合if (taskMap == null || taskMap.isEmpty()) {throw new NullPointerException();}Map<String, Future<T>> futureMap = new HashMap<String, Future<T>>();Map<String, T> messageMap = new HashMap<String, T>();boolean done = false;try {for (String key : taskMap.keySet()) {futureMap.put(key, submit(taskMap.get(key)));}for (String key : futureMap.keySet()) {Future<T> f = futureMap.get(key);try {T result = f.get();messageMap.put(key, result);} catch (ExecutionException e) {System.out.println(e.getMessage());}}done = true;return messageMap;} finally {if (!done) {for (String key : futureMap.keySet()) {futureMap.get(key).cancel(true);}}this.shutdown();}}};

多线程调用多线程需要注意的是子线程的线程池需要调大到大于8否则会导致不同步

import java.util.HashMap;import java.util.Map;import java.util.concurrent.ArrayBlockingQueue;import java.util.concurrent.Callable;import java.util.concurrent.TimeUnit;public class Test implements Callable<String> {private static final MainPoolExecutor executor = new MainPoolExecutor(3,4, 3000L, TimeUnit.MILLISECONDS, new ArrayBlockingQueue<Runnable>(10));private String name;public String getName() {return name;}public void setName(String name) {this.name = name;}public Test() {super();}public Test(String name) {this.name = name;}@Overridepublic String call() throws Exception {System.out.println(name + " 开始！");Thread.sleep(1000);System.out.println(name + " 结束！");return null;}public static void main(String[] args) {SuperTest[] testArr = new SuperTest[] { new SuperTest("父线程1"),new SuperTest("父线程2"), new SuperTest("父线程3") };Map<String, Callable<String>> taskMap = new HashMap<String, Callable<String>>();try {for (SuperTest test : testArr) {taskMap.put(String.valueOf(Math.random()), test);}executor.performTasks(taskMap);} catch (InterruptedException e) {e.printStackTrace();} finally {executor.shutdown();}}};class SuperTest implements Callable<String> {// 一共有9个线程所以 corePoolSize 和 maximumPoolSize得设置成大于等于9的数字 否则不同步private static final MainPoolExecutor executor = new MainPoolExecutor(9,9, 3000L, TimeUnit.MILLISECONDS, new ArrayBlockingQueue<Runnable>(10));private String name;public String getName() {return name;}public SuperTest() {super();}public SuperTest(String name) {this.name = name;}@Overridepublic String call() {Test[] testArr = new Test[] { new Test(name + " 子线程1"),new Test(name + " 子线程2"), new Test(name + " 子线程3") };Map<String, Callable<String>> taskMap = new HashMap<String, Callable<String>>();for (Test test : testArr) {taskMap.put(String.valueOf(Math.random()), test);}try {executor.performTasks(taskMap);} catch (InterruptedException e) {e.printStackTrace();} finally {executor.shutdown();}return null;}}

FutureTask不会阻塞主线程

import java.util.concurrent.Callable;import java.util.concurrent.ExecutorService;import java.util.concurrent.Executors;import java.util.concurrent.FutureTask;import java.util.concurrent.locks.ReadWriteLock;import java.util.concurrent.locks.ReentrantReadWriteLock;/** * FutureTask线程执行不会阻塞主线程 * @author Test * */public class NoInterruptTest implements Callable<String> {private long longTime;// 锁对象 需要放外部 否则private final ReadWriteLock lock =new ReentrantReadWriteLock();public long getLongTime() {return longTime;}public void setLongTime(long longTime) {this.longTime = longTime;}public NoInterruptTest() {super();}public NoInterruptTest(long longTime) {this.longTime = longTime;}@Overridepublic String call() throws Exception {// synchronized 用于控制同一个对象的多个线程访问lock.writeLock().lock();System.out.println(Thread.currentThread().getName()+" 开始！");Thread.sleep(longTime);System.out.println(Thread.currentThread().getName()+" 结束！");lock.writeLock().unlock() ;return "lanweixing";}public static void main(String[] args) throws Exception{long n1 = System.currentTimeMillis() ;NoInterruptTest callable1 = new NoInterruptTest(3000);NoInterruptTest callable2 = new NoInterruptTest(3000);ExecutorService executorService = Executors.newCachedThreadPool(); FutureTask<String> task1 = new FutureTask<String>(callable1);FutureTask<String> task2 = new FutureTask<String>(callable1);executorService.execute(task1);executorService.execute(task2);while(true){if(task1.isDone() && task2.isDone()){// 获得线程执行结果System.out.println(task1.get());System.out.println("任务已处理。");break ;}}System.out.println((System.currentTimeMillis()-n1)/1000);executorService.shutdown();}};