详解Java多线程处理List数据

import java.util.arraylist;

import java.util.list;

import org.apache测试数据mons.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" );

   }