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public void dealListWithMutiThread(){
List<Object> list = new ArrayList<Object>(10000);
int index = 0;
ExecutorService ex = Executors.newFixedThreadPool(5);
int dealSize = 2000;
List<Future<List<Object>>> futures = new ArrayList<>(5);
//分配
for(int i=0;i<5;i++,index+=dealSize){
int start = index;
if(start>=list.size()) break;
int end = start + dealSize;
end = end>list.size() ? list.size() : end;
futures.add(ex.submit(new Task(list,start,end)));
}
try {
//处理
List<Object> result = new ArrayList<>();
for(Future<List<Object>> future : futures){
//合并操作
result.addAll(future.get());
}
} catch (Exception e) {
e.printStackTrace();
}
}
private class Task implements Callable<List<Object>>{
private List<Object> list;
private int start;
private int end;
public Task(List<Object> list,int start,int end){
this.list = list;
this.start = start;
this.end = end;
}
@Override
public List<Object> call() throws Exception {
Object obj = null;
List<Object> retList = new ArrayList<Object>();
for(int i=start;i<end;i++){
obj = list.get(i);
//你的处理逻辑
}
//返回处理结果
return retList;
}
}
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ForkJoinPool;
import java.util.concurrent.Future;
import java.util.concurrent.RecursiveTask;
public class FJTest {
private List<String> list;
public static void main(String[] args) {
System.out.println(new FJTest().run().length());
}
private void init(){
//模拟初始化1W条数据
list = new ArrayList<String>();
for (int i = 0; i < 10000; i++) {
list.add(i + "");
}
}
public String run(){
init();
ForkJoinPool pool = new ForkJoinPool(5);
Task task = new Task(list);
Future<String> result = pool.submit(task);
String str = "";
try {
str = result.get();
} catch (InterruptedException e) {
e.printStackTrace();
} catch (ExecutionException e) {
e.printStackTrace();
}
return str;
}
class Task extends RecursiveTask<String>{
private int size = 2000;
private List<String> data;
public Task(List<String> data){
this.data = data;
}
@Override
protected String compute() {
StringBuffer sb = new StringBuffer();
if(data.size() <= size){
System.out.println("******************************** size:" + data.size());
for (String str : data) {
sb.append(str);
}
}else{
//细分成小任务
List<Task> tasks = new ArrayList<FJTest.Task>();
for (int index = 0; index * size < data.size(); index++) {
Task task;
if((index + 1) * size > data.size()){
task = new Task(data.subList(index * size, data.size()));
}else{
task = new Task(data.subList(index * size, (index + 1) * size));
}
task.fork();
tasks.add(task);
}
for (Task task : tasks) {
sb.append(task.join());
}
}
return sb.toString();
}
}
}