详解Java多线程处理List数据

import java.util.ArrayList;import java.util.List;import org.apache.commons.lang3.ArrayUtils;public class Test_4 {/*** 多线程处理list** @param data 数据list* @param threadNum 线程数*/public synchronized void handleList(List<String> data, int threadNum) {int length = data.size();int tl = length % threadNum == 0 ? length / threadNum : (length/ threadNum + 1);for (int i = 0; i < threadNum; i++) {int end = (i + 1) * tl;HandleThread thread = new HandleThread("线程[" + (i + 1) + "] ", data, i * tl, end > length ? length : end);thread.start();}}class HandleThread extends Thread {private String threadName;private List<String> data;private int start;private int end;public HandleThread(String threadName, List<String> data, int start, int end) {this.threadName = threadName;this.data = data;this.start = start;this.end = end;}public void run() {List<String> subList = data.subList(start, end)/*.add("^&*")*/;System.out.println(threadName+"处理了"+subList.size()+"条！");}}public static void main(String[] args) {Test_4 test = new Test_4();// 准备数据List<String> data = new ArrayList<String>();for (int i = 0; i < 6666; i++) {data.add("item" + i);}test.handleList(data, 5);System.out.println(ArrayUtils.toString(data));}}

//测试读取List的线程类，大概34秒package com.thread.list; import java.util.ArrayList;import java.util.HashMap;import java.util.List;import java.util.Map; public class Main {    public static void main(String[] args) {        List<String> list = new ArrayList<String>();    Map<Long,Integer> map = new HashMap<Long,Integer>();    for(int i = 0;i<1000;i++){      list.add(""+i);    }        int pcount = Runtime.getRuntime().availableProcessors();        long start = System.currentTimeMillis();            for(int i=0;i<pcount;i++){            Thread t = new MyThread1(list,map);      map.put(t.getId(),Integer.valueOf(i));      t.start();      try {        t.join();      } catch (InterruptedException e) {               e.printStackTrace();      }            // System.out.println(list.get(i));    }        System.out.println("----"+(System.currentTimeMillis() - start));  }  }//线程类package com.thread.list; import java.util.List;import java.util.Map; public class MyThread1 extends Thread {   private List<String> list;  private Map<Long,Integer> map;    public MyThread1(List<String> list,Map<Long,Integer> map){    this.list = list;    this.map = map;  }    @Override  public void run() {        int pcount = Runtime.getRuntime().availableProcessors();    int i = map.get(Thread.currentThread().getId());        for(;i<list.size();i+=pcount){      System.out.println(list.get(i));    }         }  }

public static void main(String[] args) throws Exception {    // 开始时间    long start = System.currentTimeMillis();    List<String> list = new ArrayList<String>();    for (int i = 1; i <= 3000; i++) {      list.add(i + "");    }    // 每500条数据开启一条线程    int threadSize = 500;    // 总数据条数    int dataSize = list.size();    // 线程数    int threadNum = dataSize / threadSize + 1;    // 定义标记,过滤threadNum为整数    boolean special = dataSize % threadSize == 0;    // 创建一个线程池    ExecutorService exec = Executors.newFixedThreadPool(threadNum);    // 定义一个任务集合    List<Callable<Integer>> tasks = new ArrayList<Callable<Integer>>();    Callable<Integer> task = null;    List<String> cutList = null;    // 确定每条线程的数据    for (int i = 0; i < threadNum; i++) {      if (i == threadNum - 1) {        if (special) {          break;        }        cutList = list.subList(threadSize * i, dataSize);      } else {        cutList = list.subList(threadSize * i, threadSize * (i + 1));      }      // System.out.println("第" + (i + 1) + "组：" + cutList.toString());      final List<String> listStr = cutList;      task = new Callable<Integer>() {        @Override        public Integer call() throws Exception {          System.out.println(Thread.currentThread().getName() + "线程：" + listStr);          return 1;        }      };      // 这里提交的任务容器列表和返回的Future列表存在顺序对应的关系      tasks.add(task);    }    List<Future<Integer>> results = exec.invokeAll(tasks);    for (Future<Integer> future : results) {      System.out.println(future.get());    }    // 关闭线程池    exec.shutdown();    System.out.println("线程任务执行结束");    System.err.println("执行任务消耗了 ：" + (System.currentTimeMillis() - start) + "毫秒");  }