Question

我想在localhost上创建Delphi6和Eclipse之间的套接字通信。 Delphi-Code似乎有效，我可以将数据从Delphi-Server发送到Delphi-Client。现在我想将数据从相同的Delphi-Server发送到Java-Client。以下代码我使用了几个例子。似乎已经建立了Delphi和Java之间的连接，但是在while循环（stdIn.readLine（））中，程序不再起作用了。没有例外。该程序停止工作。如何从Delphi-server读取数据？

谢谢！

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.Socket;

public class JavaClientSocketEx {
    public static void main(String[] args) {
        try {
            Socket echoSocket = new Socket("127.0.0.1", 10003);
            PrintWriter out =
                new PrintWriter(echoSocket.getOutputStream(), true);
            BufferedReader in =
                new BufferedReader(
                    new InputStreamReader(echoSocket.getInputStream()));
            BufferedReader stdIn =
                new BufferedReader(
                    new InputStreamReader(System.in));
            String userInput;
            echoSocket.close();
            while ((userInput = stdIn.readLine()) != null) { // at this point the programm doesnt work anymore!
                out.println(userInput);
                System.out.println("echo: " + in.readLine());
            }
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } 
    }
}

编辑：Delphi代码

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, ScktComp, ExtCtrls, StdCtrls;

type
  CustomRec = record
    Zahl: byte;
end;
TForm1 = class(TForm)
    Edit1: TEdit;
    Timer1: TTimer;
    sendenButton: TButton;
    Edit2: TEdit;
    ClientSocket1: TClientSocket;
    ServerSocket1: TServerSocket;
    procedure Timer1Timer(Sender: TObject);
    procedure FormActivate(Sender: TObject);
    procedure sendenButtonClick(Sender: TObject);
    procedure ServerSocket1ClientError(Sender: TObject;
      Socket: TCustomWinSocket; ErrorEvent: TErrorEvent;
      var ErrorCode: Integer);
    procedure ServerSocket1ClientRead(Sender: TObject;
      Socket: TCustomWinSocket);
    procedure ClientSocket1Error(Sender: TObject; Socket: TCustomWinSocket;
      ErrorEvent: TErrorEvent; var ErrorCode: Integer);
  private
    { Private-Deklarationen }
  public
    { Public-Deklarationen }
  end;

var
  Form1: TForm1;
  senden : boolean;

implementation

{$R *.dfm}

procedure TForm1.Timer1Timer(Sender: TObject);
var
text : string;
begin

        text :=  Edit1.Text;
        ClientSocket1.Socket.SendText(text);

end;

procedure TForm1.FormActivate(Sender: TObject);
begin
        sendenButton.Caption := 'Send';
        senden := false;
        ClientSocket1.Port := 10003;
        ClientSocket1.Host := '127.0.0.1';
        ClientSocket1.Active := true;
        ServerSocket1.Port := 10003;
        ServerSocket1.Active := true;

end;

procedure TForm1.sendenButtonClick(Sender: TObject);
begin

  if senden then
   begin
        senden := false;
        sendenButton.Caption := 'Send';
        Timer1.Enabled := false;
   end
  else
   begin
        senden :=true;
        sendenButton.Caption := 'Stopp';
        Timer1.Enabled := true;
  end;
end;

procedure TForm1.ServerSocket1ClientError(Sender: TObject;
  Socket: TCustomWinSocket; ErrorEvent: TErrorEvent;
  var ErrorCode: Integer);
begin
Errorcode := 0;
end;

procedure TForm1.ServerSocket1ClientRead(Sender: TObject;
  Socket: TCustomWinSocket);
var  Rec: CustomRec;
begin
     edit2.Text := Socket.ReceiveText;
     rec.Zahl:=StrToInt(Edit2.Text);
     Socket.SendBuf(Rec,sizeof(Rec));
end;

procedure TForm1.ClientSocket1Error(Sender: TObject;
  Socket: TCustomWinSocket; ErrorEvent: TErrorEvent;
  var ErrorCode: Integer);
begin
Errorcode :=0;
end;

end.

在点击＆＃34; sendenButton＆＃34;之后，delphi-client开始在一秒间隔内定期发送第一个edit-Element（即输入）的数据。第二个edit-Element是接收数据的输出。在我再次点击此按钮后停止发送。

Answer 1

问题可能出在while循环中，您尝试在已经关闭的套接字上进行读写。
```
echoSocket.close();
while ((userInput = stdIn.readLine()) != null) { // at this point the programm doesnt work anymore!
  out.println(userInput);
  . . .
```
这可以通过循环后移动echoSocket.close();来解决之后，Java客户端工作;现在问题出在服务器上。
Delphi客户端绑定到服务器并优先于Java服务器要解决此问题，请禁用Delphi客户端：
```
//ClientSocket1.Active := true;
```
之后服务器正常工作。
此时，当您通过控制台发送号码时，请说42，服务器会引发异常：

项目Project1.exe引发了一个异常类EConvertError，消息为''42
'不是有效的整数值'。

问题出现在ServerSocket1ClientRead mehod中，并附带此说明：
```
rec.Zahl := StrToInt(Edit2.Text);
```
因为sockect收到的字符串是
```
'42'#$D#$A
```
您可以考虑清理文本：
```
rec.Zahl := StrToInt(StringReplace(Trim(Edit2.Text), '''', '', [rfReplaceAll]));
```
将回复发送到客户端时，消息终结符#$D#$A丢失。这条线
```
Socket.SendBuf(Rec, sizeof(Rec));
```
必须像
一样进行更改
```
Socket.SendText(IntToStr(rec.Zahl) + #13#10);
```
这解决了阻止客户端问题。

已编辑的程序如下 - 我已将逻辑从OnActivate移至OnCreate表单事件：

Delphi服务器/客户端

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, ScktComp, ExtCtrls, StdCtrls;

type
  CustomRec = record
    Zahl: Byte;
  end;

TForm1 = class(TForm)
  Edit2: TEdit;
    Edit1: TEdit;
    sendenButton: TButton;
  procedure ServerSocket1ClientError(Sender: TObject;
    Socket: TCustomWinSocket; ErrorEvent: TErrorEvent;
    var ErrorCode: Integer);
  procedure ServerSocket1ClientRead(Sender: TObject;
    Socket: TCustomWinSocket);
  procedure ClientSocket1Error(Sender: TObject; Socket: TCustomWinSocket;
    ErrorEvent: TErrorEvent; var ErrorCode: Integer);
  procedure FormCreate(Sender: TObject);
    procedure sendenButtonClick(Sender: TObject);
private
  { Private-Deklarationen }
  ClientSocket1: TClientSocket;
  ServerSocket1: TServerSocket;
public
  { Public-Deklarationen }
end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.FormCreate(Sender: TObject);
begin
  ClientSocket1 := TClientSocket.Create(Self);
  ClientSocket1.OnError := ClientSocket1Error;

  ServerSocket1 := TServerSocket.Create(Self);
  ServerSocket1.OnClientError := ServerSocket1ClientError;
  ServerSocket1.OnClientRead := ServerSocket1ClientRead;

  ClientSocket1.Port := 10003;
  ClientSocket1.Host := '127.0.0.1';
  //ClientSocket1.Open;

  ServerSocket1.Port := 10003;
  ServerSocket1.Open;
end;

procedure TForm1.sendenButtonClick(Sender: TObject);
begin
  sendenButton.Enabled := False;
  ClientSocket1.Open;
  ClientSocket1.Socket.SendText(Edit1.Text);
  ClientSocket1.Close;
  sendenButton.Enabled := True;
end;

procedure TForm1.ServerSocket1ClientError(Sender: TObject;
  Socket: TCustomWinSocket; ErrorEvent: TErrorEvent;
  var ErrorCode: Integer);
begin
  Errorcode := 0;
end;

procedure TForm1.ServerSocket1ClientRead(Sender: TObject; Socket: TCustomWinSocket);
var
  rec: CustomRec;
  sInt, reply: string;
  iInt, iCode: Integer;
begin
  edit2.Text := Socket.ReceiveText;

  sInt := StringReplace(Trim(Edit2.Text), '''', '', [rfReplaceAll]);
  Val(sInt, iInt, iCode);

  if iCode = 0 then begin
    if iInt in [Low(Byte)..High(Byte)] then begin
      rec.Zahl := iInt;
      reply := IntToStr(rec.Zahl);
    end;
  end
  else
    reply := '-1';

  Socket.SendText(reply + #13#10);
end;

procedure TForm1.ClientSocket1Error(Sender: TObject;
  Socket: TCustomWinSocket; ErrorEvent: TErrorEvent;
  var ErrorCode: Integer);
begin
  Errorcode := 0;
end;

end.

Java客户端

public static void main(String[] args) throws UnknownHostException, IOException {

    Socket echoSocket = new Socket("127.0.0.1", 10003);
    try {
        PrintWriter out = new PrintWriter(echoSocket.getOutputStream(), true);
        BufferedReader in = new BufferedReader(new InputStreamReader(echoSocket.getInputStream()));
        BufferedReader stdIn = new BufferedReader(new InputStreamReader(System.in));
        String userInput;

        while ((userInput = stdIn.readLine()) != null) {

            //the next 2 lines resume like: if you have to die, die fast
            int value = Integer.parseInt(userInput);//ensure that input is an Integer
            assert (value >= 0 && value <= 255);// ensure that the Integer is in the Delphi's Byte range

            out.println(value);

            System.out.println("server replies: " + in.readLine());
        }
    } finally {
        echoSocket.close();
    }            
}

除了使用writeLine和readLine的实现之外，还可以使用DataOutput.writeUTF和DataInput.readUTF方法向服务器发送消息并从中读取消息：

Socket echoSocket = new Socket("127.0.0.1", 10003);
OutputStream os = echoSocket.getOutputStream();
DataOutputStream out = new DataOutputStream(os);
out.writeUTF("Hi, it's me!");//your message to the server

InputStream in = echoSocket.getInputStream();
DataInputStream din = new DataInputStream(in);
System.out.println("Server response: " + din.readUTF());

echoSocket.close();

Answer 2

现在我找到了解决问题的方法。非常感谢你的建议，fantaghirocco，它帮助我找到答案。我似乎不理解服务器 - 客户端架构的原则。我修改了你的代码，现在它对我来说很好。

的Delphi码：

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, ScktComp, ExtCtrls, StdCtrls;

type
  CustomRec = record
    Zahl: Byte;
  end;

TForm1 = class(TForm)
    edit1: TEdit;
    ClientSocket1: TClientSocket;
    ServerSocket1: TServerSocket;
    Label1: TLabel;
  procedure ServerSocket1ClientError(Sender: TObject;
    Socket: TCustomWinSocket; ErrorEvent: TErrorEvent;
    var ErrorCode: Integer);
  procedure MyServerSocket1ClientRead(Sender: TObject;
    Socket: TCustomWinSocket);
  procedure ClientSocket1Error(Sender: TObject; Socket: TCustomWinSocket;
    ErrorEvent: TErrorEvent; var ErrorCode: Integer);
    procedure FormActivate(Sender: TObject);
private
public
  { Public-Deklarationen }
end;

var
  Form1: TForm1;

implementation

{$R *.dfm}


procedure TForm1.ServerSocket1ClientError(Sender: TObject;
  Socket: TCustomWinSocket; ErrorEvent: TErrorEvent;
  var ErrorCode: Integer);
begin
  Errorcode := 0;
end;

procedure TForm1.MyServerSocket1ClientRead(Sender: TObject; Socket: TCustomWinSocket);
var
  rec: CustomRec;
  sInt, reply: string;
  iInt, errorPos: Integer;
begin
  edit1.Text := Socket.ReceiveText;

  sInt := StringReplace(Trim(Edit1.Text), '''', '', [rfReplaceAll]);
  Val(sInt, iInt, errorPos);

  if errorPos = 0 then begin
    if iInt in [Low(Byte)..High(Byte)] then begin
      rec.Zahl := iInt;
      iInt := iInt +1;
      reply := IntToStr(rec.Zahl);
    end;
  end
  else
    reply := '-1';
    reply := 'reply ' + reply + ' accepted';
  Socket.SendText(reply + #13#10);
end;

procedure TForm1.ClientSocket1Error(Sender: TObject;
  Socket: TCustomWinSocket; ErrorEvent: TErrorEvent;
  var ErrorCode: Integer);
begin
  Errorcode := 0;
end;

procedure TForm1.FormActivate(Sender: TObject);
begin
  ClientSocket1 := TClientSocket.Create(Self);
  ClientSocket1.OnError := ClientSocket1Error;

  ServerSocket1 := TServerSocket.Create(Self);
  ServerSocket1.OnClientError := ServerSocket1ClientError;
  ServerSocket1.OnClientRead := MyServerSocket1ClientRead;

  ClientSocket1.Port := 10003;
  ClientSocket1.Host := '127.0.0.1';

  ServerSocket1.Port := 10003;
  ServerSocket1.Open;
end;

end.

的Delphi-形式：

Java的代码：

class TCPClient {
    private static int input;
public static void main(String[] args) throws UnknownHostException, IOException {

    Socket echoSocket = new Socket("127.0.0.1", 10003);
    Timer timer = new Timer();
    input = 0;
    timer.schedule(new TimerTask() {
        @Override
        public void run() {
            try {
                input = input +1;
                doTime(echoSocket, input);
            } catch (IOException e) {
                e.printStackTrace();
            }  
        }
    }, 1000,1000);   
}

private static void doTime(Socket echoSocket, int input) throws IOException {
    try {
        PrintWriter out = new PrintWriter(echoSocket.getOutputStream(), true);
        BufferedReader in = new BufferedReader(new InputStreamReader(echoSocket.getInputStream()));
        //the next 2 lines resume like: if you have to die, die fast
        int value = input;//ensure that input is an Integer
        assert (value >= 0 && value <= 255);// ensure that the Integer is in the Delphi's Byte range
        System.out.println("sending server reply number : " + value);
        out.println(value);
        System.out.println("server replies: " + in.readLine());

    } finally {
        //  echoSocket.close();
    }
}

}

Delphi与Java之间的套接字通信

2 个答案: