多线程分批处理list内的值

时间:2022-03-12 23:04:14
package three;

import java.util.LinkedList;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;


/**
*
* 这个方法没有返回值,不能接到最后的处理结果
*
*/
public class MyExecutors {
private static LinkedList<Integer> list = new LinkedList<Integer>();

public static void main(String[] args) throws InterruptedException {
for (int i = 0; i < 100; i++) {
list.add(i);
}

// 创建线程池
ExecutorService executorService = Executors.newFixedThreadPool(90);
for (Integer every : list) {
executorService.execute(
new Runnable() {
@Override
public void run() {
System.out.println(Thread.currentThread().getName()
+ " " + every);
}
});
}
System.out.println(
"------------------------------------------");
// 任务执行完毕后结束线程
executorService.shutdown();
}
}




//---------------------------------------------------下面的这个类是智慧的网友写的,有返回值--------------------------------------------------------------------------
package four;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;

public class CunsumerList {
public static void main(String[] args) {
try {
List
<String> list = new ArrayList<>();
for (int i = 0; i < 100; i++) {
list.add(i
+ ",");
}

System.out.println(
new CunsumerList().list2Str(list, 5));
}
catch (Exception e) {
e.printStackTrace();
}
}
/**
* 这个能知道线程的处理结果,因为有返回值
*
@param list
*
@param nThreads
*
@return
*
@throws Exception
*/
public String list2Str(List<String> list, final int nThreads) throws Exception {
if (list == null || list.isEmpty()) {
return null;
}

StringBuffer ret
= new StringBuffer();

int size = list.size();
ExecutorService executorService
= Executors.newFixedThreadPool(nThreads);
List
<Future<String>> futures = new ArrayList<Future<String>>(nThreads);


for (int i = 0; i < nThreads; i++) {
final List<String> subList = list.subList(size / nThreads * i, size / nThreads * (i + 1));
Callable
<String> task = new Callable<String>() {
@Override
public String call() throws Exception {
System.out.println(Thread.currentThread().getName());
StringBuffer sb
= new StringBuffer();
for (String str : subList) {
sb.append(str);
}
return sb.toString();
}
};
futures.add(executorService.submit(task));
}
for (Future<String> future : futures) {
ret.append(future.get());
}
executorService.shutdown();

return ret.toString();
}
}