java - 即使没有 dekker/peterson 的算法，Java 中的多线程也能工作吗？

Question

是的，这是一项家庭作业，但我已经尝试了所有可能的方法，但无法想出一个可能的方案。这个作业的目的是为了说明，在实现dekker算法/peterson算法之前，很可能两个进程不会先后走下去。

 import java.util.*;

public class myProcess
{

     private static final Random R = new Random();
     private int id;


     public myProcess(int i){
         id = i;
    }


    private static void delay(int value){

         try{
             java.lang.Thread.sleep(R.nextInt(value));
         }
         catch(InterruptedException e){
         }
     }

     public void run(){              

         System.out.println("");
         delay(20);
         System.out.println(this.id + " is starting");
         delay(20);
         System.out.println("LINE ONE");
         delay(20);
         System.out.println("LINE TWO");
         delay(20);
         System.out.println("LINE THREE");
         delay(20);
         System.out.println(this.id+ " is ending ");
         delay(20);

     }

     public static void main(String [] args){
         final int N = 2;
         myProcess[] t = new myProcess[N];

         for(int i = 0; i < N; i++){
             t[i] = new myProcess(i);
             t[i].run();

         }


  }

现在的输出是

 0 is starting
 LINE ONE
 LINE TWO
 LINE THREE
 0 is ending
 1 is starting
 LINE ONE
 LINE TWO
 LINE THREE
 1 is ending

但应该将其全部混合起来，以说明进程不一定要等待另一个进程完成。

我尝试了其他定义 run() 的方法，例如

 String[] statements = new String[5];
         statements[0] = "Thread " + this.id + " is starting iteration ";
         statements[1] = "We hold these truths to be self-evident, that all men are          created equal,";
         statements[2] = "that they are endowed by their Creator with certain unalienable Rights,";
         statements[3] = "that among these are Life, Liberty and the pursuit of Happiness.";
         statements[4] = "Thread " + this.id+ " is done with iteration ";

    for(int i = 0; i< 5; i++){

        System.out.println(statements[i]);
        delay(20);
    } 

但它仍然没有返回给我任何“错误的输出”

我做错了什么，导致输出如此正确？

Answer 1

您应该在线程上调用 start() 函数，而不是 run()。

编辑:您的类还应该实现 Runnable 接口(interface)或扩展 Thread 类。

您没有在代码中创建新线程，所有内容都在一个线程中运行。

public class myProcess extends Thread

...

for(int i = 0; i < N; i++){
    t[i] = new myProcess(i);
    t[i].start();
}