Question

所以我必须做一些简单的客户端 - 服务器程序。服务器端 `

public static void main(String[] args) throws IOException
{
    ServerSocket ss = null;
    try{ss= new ServerSocket(119);}
    catch(IOException ioe){System.out.println("Can't connect to port.");}

    Socket sock = null;
    try{sock = ss.accept();}
    catch(IOException ioe){System.out.println("Can't connect to client.");}
    System.out.println("Connection successful.");

    PrintStream out = null;
    Scanner in = null;

    try{
        out = new PrintStream(sock.getOutputStream());
        in = new Scanner(sock.getInputStream());
    }catch(Exception e)
    {
        System.out.println("Error.");
    }

    String line;
    String lines = "";

    while((line = in.nextLine()) != null)
    {
        switch(line)
        {
        case "list":out.println("Printing something");break;
        case "loop":
        {
            FileReader fr = new FileReader("D:\\Eclipse\\TestFiles\\text2.txt");
            BufferedReader br = new BufferedReader(fr);
            while((lines = br.readLine()) != null)
            {
                out.println(lines);
            }
            break;
        }
        default:
        {
            if(!(line.equals("end"))) out.println("Unknown command.Try again.");break;
        }
        }
        out.flush();
        if(line.equals("end"))
        {
            out.println("Connection over.");
            break;
        }
    }

    try{
        in.close();
        out.close();
        sock.close();
        ss.close();
    }catch(IOException ioe){}

}

`

客户端

public static void main(String[] args)
{
    Socket sock = null;
    PrintStream out = null;
    Scanner in = null;
    Scanner sIn = null;

    try{
        sock = new Socket("localhost",119);
        out = new PrintStream(sock.getOutputStream());
        in = new Scanner(sock.getInputStream());
        sIn = new Scanner(System.in);
    }catch(Exception e){
        System.out.println("Error connecting to server.");
        System.exit(1);
    }

    System.out.println("Connection successful.");

    String temp = "";

    while((temp = sIn.nextLine()) != null)
    {
        out.println(temp);
        while(in.hasNextLine())System.out.println(in.nextLine());
        out.flush();
        if(temp.equals("end")) break;
    }

    try{
        sock.close();
        in.close();
        out.close();
    }catch(IOException ioe){}

}

我的问题是，在客户端，当第二个while循环（第一个while循环内部）必须结束时，它不会，我只是在客户端输入命令而没有任何响应

Answer 1

<强>修复

使用PrintWriter来写入套接字，使用BufferedReader来读取套接字。在PrintWriter中打开auto flush mode，在下面的语句中为true表示。通过这种方式，您不必担心冲洗流。
```
PrintWriter out = new PrintWriter(sock.getOutputStream(),true);
```
你的结束语句在循环内，它会关闭流，你不能在下一次迭代中使用它们，因为你会得到一个exception。将它们拉出while循环。
用于分隔交换机中案例的不必要的大括号。
您的连接终止声明应该不在切换案例中。只有这样，break才会对循环产生影响，而不是在开关上。

我使用br.ready()来检测流是否已准备好被读取，然后迭代循环。这比您的版本有效。

while((temp = sIn.nextLine()) != null)
{
    out.println(temp);
    Thread.currentThread().sleep(1000);
    while(in.ready())System.out.println(in.readLine());
    out.flush();
    if(temp.equals("end")) break;
}

Thread.currentThread（）。sleep（1000），是获取主线程的句柄并将其休眠1000ms，这样我就可以准备好服务器响应了。否则br.ready（）对于当前请求将为false，并在下一次迭代中准备就绪。我想你知道我想传达什么。

我没有检查案例循环;

服务器

import java.net.*; import java.io.*; import java.util.*; public class chatServer { public static void main(String[] args) throws IOException { ServerSocket ss = null; try { ss= new ServerSocket(8000); } catch(IOException ioe){System.out.println("Can't connect to port.");} Socket sock = null; try{sock = ss.accept();} catch(IOException ioe){System.out.println("Can't connect to client.");} System.out.println("Connection successful."); PrintWriter out = null; Scanner in = null; try{ out = new PrintWriter(sock.getOutputStream(),true); in = new Scanner(sock.getInputStream()); }catch(Exception e) { System.out.println("Error."); } String line; String lines = ""; while((line = in.nextLine()) != null) { switch(line) { case "list": out.println("1. bla | 2. ble | 3. bli");break; case "group":out.println("Here group will be chosen.");break; case "header":out.println("Returns header.");break; case "loop": FileReader fr = new FileReader("D:\\Eclipse\\TestFiles\\text2.txt"); BufferedReader br = new BufferedReader(fr); while((lines = br.readLine()) != null) { out.println(lines); } break; default: if(!(line.equals("end"))) { out.println("Unknown command.Try again."); break; } } if(line.equals("end")) { out.println("Connection over."); break; } } try{ in.close(); out.close(); sock.close(); ss.close(); }catch(IOException ioe){} }

}

<强>客户端

import java.net.*; import java.io.*; import java.util.*; public class chatClient { public static void main(String[] args) throws IOException, InterruptedException { Socket sock = null; PrintStream out = null; BufferedReader in = null; Scanner sIn = null; try { sock = new Socket("localhost",8000); out = new PrintStream(sock.getOutputStream()); in = new BufferedReader(new InputStreamReader(sock.getInputStream())); sIn = new Scanner(System.in); } catch(Exception e) { System.out.println("Error connecting to server."); System.exit(1); } System.out.println("Connection successful."); String temp = ""; while((temp = sIn.nextLine()) != null) { out.println(temp); Thread.currentThread().sleep(1000); while(in.ready())System.out.println(in.readLine()); out.flush(); if(temp.equals("end")) break; } try { sock.close(); in.close(); out.close(); } catch(IOException ioe){} }

}

在客户端 - 服务器程序中循环

1 个答案: