有返回值的多線程

package com.example.demo.demo; import java.util.concurrent.*; import java.util.Date; import java.util.List; import java.util.ArrayList; /** * 有返回值的線程 */ @SuppressWarnings("unchecked") public class Test { public static void main(String[] args) throws ExecutionException, InterruptedException { System.out.println("----程序開始運行----"); Date date1 = new Date(); int taskSize = 5; // 創建一個線程池 ExecutorService pool = Executors.newFixedThreadPool(taskSize); // 創建多個有返回值的任務 List<Future> list = new ArrayList<Future>(); for (int i = 0; i < taskSize; i++) { Callable c = new MyCallable(i + " "); // 執行任務並獲取Future對象 Future f = pool.submit(c); // System.out.println(">>>" + f.get().toString()); list.add(f); } // 關閉線程池 pool.shutdown(); // 獲取所有併發任務的運行結果 for (Future f : list) { // 從Future對象上獲取任務的返回值，並輸出到控制檯 System.out.println(">>>" + f.get().toString()); } Date date2 = new Date(); System.out.println("----程序結束運行----，程序運行時間【" + (date2.getTime() - date1.getTime()) + "毫秒】"); } } class MyCallable implements Callable<Object> { private String taskNum; MyCallable(String taskNum) { this.taskNum = taskNum; } public Object call() throws Exception { System.out.println(">>>" + taskNum + "任務啓動"); Date dateTmp1 = new Date(); Thread.sleep(1000); Date dateTmp2 = new Date(); long time = dateTmp2.getTime() - dateTmp1.getTime(); System.out.println(">>>" + taskNum + "任務終止"); return taskNum + "任務返回運行結果,當前任務時間【" + time + "毫秒】"; } } 注意 1返回值要 f.get().toString()這樣才能轉