将对象传递给线程(访问线程外部的对象)

时间:2016-12-31 18:03:33

标签: java multithreading java-threads

我正在做一个简单的服务器 - 客户端系统。

服务器启动,创建一个只存储信息的对象,然后在收到连接后,创建一个运行线程的新对象。

对于每个线程我想传递第一个对象作为参数来改变它(添加/获取信息),但我认为传递它的东西不是。发现它尝试我的第一次尝试菜单并尝试做的事情。

已经看到一些有关此问题的帖子,但我无法弄清楚如何申请我的代码。

这是服务器代码:

import java.io.*;
import java.net.*;
import java.net.*;

public class Servidor {

    static final int PORT = 8000;

    public static void main(String args[]) {
        ServerSocket serverSocket = null;
        Socket socket = null;
        int i = 0;

        //the object that will only store info
        WorkLoad wk;
        wk = new WorkLoad();

        try {
            serverSocket = new ServerSocket(PORT);
            System.out.println("Leiloes do Ave 2097");
        } catch (IOException e) {
            e.printStackTrace();

        }
        while (true) {
            try {
                socket = serverSocket.accept();
            } catch (IOException e) {
                System.out.println("I/O error: " + e);
            }
            // new thread passing the previously created object
            //new WorkLoad(socket, wk).start();
            Thread t = new Thread(new WorkLoad(socket, wk));
            t.start();
        }

    }
}

将要完成这些工作的课程:

import java.net.*;
import java.util.*;
import java.io.*;
import java.lang.*;


public class WorkLoad extends Thread implements Runnable {
    protected Socket socket;
    //private int y; //usado no menu?
    private int clientes;
    private int leiloes;
    private int tid; //thread id
    private HashMap<Integer,Cliente> lClientes; //lista de todos os clientes existentes <ID,Cliente()>
    private HashMap<Integer,Leilao> lLeiloes; //lista de todos os leilões existents <ID, Leilao()>
    private HashMap<Integer,String> lThreads; //lista das threads
    private String[] menu = new String[10];
   // the construtor of the object to store info
    public WorkLoad() { this.clientes = 0; this.leiloes = 0 ; this.tid = 0;} //fazer sempre ++ ao criar
    // and here what i thought would pass the object to the thread, the thread constructor
    public WorkLoad(Socket clientSocket, WorkLoad wk) {
        this.socket = clientSocket;
        //this.tid = id;
        //wk.addTid(id,"");
    }

    public HashMap<Integer,Cliente> getListaClientes() { return this.lClientes; }
    public HashMap<Integer,Leilao> getListaLeiloes() { return this.lLeiloes; }
    public void addCliente(Integer id, Cliente c) { this.lClientes.put(id,c); }
    public void addLeilao(Integer id, Leilao l) { this.lLeiloes.put(id,l); }
    public int getTotalLeiloes() { return this.leiloes; }
    public int getTotalClientes() { return this.clientes; }
    public void addTid(int id,String s) { lThreads.put(id,s); } //adiciona thread lista
    public int getTid() { return this.tid; }
    public String getTidMsg(int id) { return lThreads.get(id);} //devolve mensagem da lista de threads
    public Leilao getLeilao(Integer id) { return this.lLeiloes.get(id); } //devolve o leilao pela id



    public void run() {

        PrintWriter out = null;
        BufferedReader in = null;
        DataOutputStream cout = null;
       //private HashMap<Integer,String> lThreads;
        //MENU
        menu[0] = "1"; //menu de escolha menu[0] = MENU.A.APRESENTAR
        menu[1] = "- Registo de utilizador - :insere o username e depois a password\n"; //tem de fazer 2 readlines
        menu[2] = "- Login de utilizador - :insere o username e depois a password\n"; //tem de fazer 2 readlines
        menu[3] = "- Menu geral - :1)Criar Leilao:2)Listar Leiloes:3)Licitar leilao:4)Terminar Leilao:Para sair escreva exit\n";
        menu[4] = "- Licitar leilao - :Insere o id de leilao e depois o valor da tua licitação com . (ex 5.5)\n"; //tem de fazer 2 readlines
        menu[5] = "- Criar leilao - :Insere a descricao do item\n";
        menu[6] = "- Terminar Leilao -:Insere a id do leilao que queres terminar\n";


        try {
            //System.out.println(socket.getInetAddress() + " entrou.");
            //ArrayList<String>
            out = new PrintWriter(socket.getOutputStream());
            in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
            //v2
            cout = new DataOutputStream(socket.getOutputStream());            
            cout.writeBytes("Bem vindo ao leilões do Ave :1) Registo :2) login :exit para sair.\n");

            String input;
            //cria nova instancia de cliente
            Cliente clithread = new Cliente(wk.getTotalClientes());

             //while((input = in.readLine()) != null) {
             while(true) {
                input = in.readLine(); //Lê uma linha - tem de se tratar linha a linha
                if(input.equals("exit")) { in.close(); cout.close(); socket.close(); return; }
                if(input.equals("1")) { } // registo cliente
                //cout.writeBytes(menu[input.toString()]); //print menu registo
                //input = in.readLine(); //lê username
                //cout.writeBytes("Recebi a mensagem:" + input + "\n"); //POR O \n no fim ou o cliente nao funciona direito!!
                //System.out.println(input); //print no server local
             }

           // in.close();
           // out.close();
          //  socket.close();

        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

    }



}

当我试图访问run()中的wk.get时,我注意到了我的问题,并且说它无法找到该对象。

2 个答案:

答案 0 :(得分:4)

这里有几件事情。

每次获得连接时都会创建一个新的WorkLoad对象。我认为您希望所有与共享的连接都是您在程序开始时创建的WorkLoad,但这不是正在发生的事情。

第一次连接后,您有两个WorkLoad对象:在程序开头创建的对象,以及您在此处创建的对象:

Thread t = new Thread(new WorkLoad(socket, wk));

第二个问题是你如何定义Thread对象。

  • 线程已经实现了Runnable,因此如果您已经有“extends Thread”,则不需要“implements Runnable”。
  • WorkLoad是一个Thread(“extends Thread”),所以你不需要将它包装在另一个线程中(“new Thread(new Workload(...))”)。

如果您希望在多个线程之间共享一个WorkLoad,则需要将WorkLoad(其中只有一个)的概念与线程的概念(您将拥有多个线程)分开。

  • 没有WorkLoad扩展Thread或实现Runnable。删除套接字成员。
  • 创建一个实现Runnable且具有Socket成员的新类(Worker?)。

当您获得新连接时,请执行以下操作:

Thread t = new Thread(new Worker(socket, wk));
t.start();

答案 1 :(得分:2)

好的....你的代码中很多东西都很可疑。

  1. wk永远不会保存在本地。因此,无法通过代码读取 线程已启动
  2. 使用Thread和implements来对类进行子类化 Runnable接口。这是完全错误的。你可以扩展Thread或 实现Runnable以有效地完成它。
  3. 所以我建议的是; 将构造函数更改为

      Workload(Socket socket) {
        this.clientes = 0; this.leiloes = 0 ; this.tid = 0;
        this.socket = socket;
      }
    

    无需创建一个Workload对象并将其传递给另一个Workload对象。