Java中创建线程的三种方式及其优缺点
1.自定义一个继承Thread的类，由于Java的单继承特性，限制了该类的扩展性。
2.实现Runnable接口，重写run()方法。
3.实现Callable接口，重写call方法。线程执行体可以有返回值，并且可以抛出异常。
1 import java.util.concurrent.Callable; 2 import java.util.concurrent.ExecutionException; 3 import java.util.concurrent.FutureTask; 4 5 public class Main { 6 public static void main(String[] args) { 7 // 1.继承Thread类 8 new DefineThread().start(); 9 // 2.实现Runnable接口 10 new Thread(new DefineRunnable()).start(); 11 // 3.实现Callable接口 12 new Thread(futureTask).start(); 13 String result = ""; 14 try { 15 result = futureTask.get(); 16 } catch (InterruptedException e) { 17 e.printStackTrace(); 18 } catch (ExecutionException e) { 19 //ExecutionException封装了call()方法抛出的异常 20 e.printStackTrace(); 21 e.getCause(); 22 //getCause()方法把被包装的原始异常提取出来 23 } 24 System.out.println(result); 25 } 26 27 static class DefineThread extends Thread { 28 29 @Override 30 public void run() { 31 for (int i = 0; i < 100; i++) { 32 String name2 = getName(); 33 try { 34 sleep(100); 35 } catch (InterruptedException e) { 36 e.printStackTrace(); 37 } 38 System.out.println(name2 + ": " + i); 39 } 40 } 41 } 42 43 static class DefineRunnable implements Runnable { 44 45 @Override 46 public void run() { 47 for (int i = 0; i < 100; i++) { 48 // String name2 = getName(); 49 String name = Thread.currentThread().getName(); // 实现runnable接口，使用Thread类的currentThread()获取当前线程对象 50 try { 51 Thread.currentThread().sleep(100); 52 } catch (InterruptedException e) { 53 e.printStackTrace(); 54 } 55 System.out.println(name + ": " + i); 56 } 57 } 58 } 59 60 static FutureTask<String> futureTask = new FutureTask<>(new Callable<String>() { 61 62 @Override 63 public String call() throws InterruptedException { 64 String name = ""; 65 int i = 0; 66 for (; i < 100; i++) { 67 name = Thread.currentThread().getName(); 68 Thread.currentThread().sleep(100); 69 System.out.println(name + ": " + i); 70 } 71 return name + " ----->Result=" + i; 72 } 73 }); 74 }
