Java多线程处理List数据的三个示例（代码）

实例1：

解决问题：如何让n个线程顺序遍历含有n个元素的List集合

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)); } }

实例2：

List多线程并发读取读取现有的list对象

//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));         }                   }     }

实例3：

多线程分段处理List集合

List集合分段,

将对比操作在多线程中实现

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");   }

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