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
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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
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//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
场景:大数据list集合,需要对list集合中的数据同标准库中数据进行对比,生成新增,更新,取消数据
解决方案:
- list集合分段,
- 动态创建线程池newfixedthreadpool
- 将对比操作在多线程中实现
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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"); } |
以上所述是小编给大家介绍的java多线程处理list数据详解整合，希望对大家有所帮助，如果大家有任何疑问请给我留言，小编会及时回复大家的。在此也非常感谢大家对服务器之家网站的支持！
