Java 试图让一个简单的回声客户端服务器程序在两台计算机之间工作
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/20103736/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
Trying to make a simple echo client server program work between two computers
提问by kofhearts
I have been trying to resolve this issue but with no success so finally i am here to get some help from experts.
我一直在尝试解决这个问题，但没有成功，所以最后我在这里寻求专家的帮助。
I just wanted to make a simple client server program work between two computers.
我只是想让一个简单的客户端服务器程序在两台计算机之间工作。
The server will reside in my laptop which is connected to the internet through a linksys router.
服务器将驻留在我的笔记本电脑中，该笔记本电脑通过 linksys 路由器连接到互联网。
The client will reside in a university computer. I scped the file to a university computer and then i run it through ssh.
客户端将驻留在大学计算机中。我将文件 scped 到大学计算机，然后通过 ssh 运行它。
Now also two things worth noting is that i have also disabled firewall in my computer as well as i have configured port forwaring in my linksys router i.e it will forward request to the port to my ipaddress. I have also made my ipadddress static.
现在还有两件值得注意的事情是，我还在我的计算机中禁用了防火墙，并且我在我的 linksys 路由器中配置了端口转发，即它将请求转发到我的 ipaddress 的端口。我也使我的 ipaddaddress 是静态的。
Here is the server code to reside in my laptop.
这是驻留在我的笔记本电脑中的服务器代码。
/* EchoServer.java
*
* Copyright (c) 2000 Sean Walton and Macmillan Publishers. Use may be in
* whole or in part in accordance to the General Public License (GPL).
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/*****************************************************************************/
/*** EchoServer.java ***/
/*** ***/
/*****************************************************************************/
import java.io.*;
import java.net.*;
public class EchoServer
{
public EchoServer(int portnum)
{
try
{
server = new ServerSocket(portnum);
}
catch (Exception err)
{
System.out.println(err);
}
}
public void serve()
{
try
{
while (true)
{
Socket client = server.accept();
BufferedReader r = new BufferedReader(new InputStreamReader(client.getInputStream()));
PrintWriter w = new PrintWriter(client.getOutputStream(), true);
w.println("Welcome to the Java EchoServer. Type 'bye' to close.");
String line;
do
{
line = r.readLine();
if ( line != null )
w.println("Got: "+ line);
}
while ( !line.trim().equals("bye") );
client.close();
}
}
catch (Exception err)
{
System.err.println(err);
}
}
public static void main(String[] args)
{
EchoServer s = new EchoServer(3000);
s.serve();
}
private ServerSocket server;
}
Here is the client code that will reside in university computer.
这是将驻留在大学计算机中的客户端代码。
/* EchoClient.java
*
* Copyright (c) 2000 Sean Walton and Macmillan Publishers. Use may be in
* whole or in part in accordance to the General Public License (GPL).
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/*****************************************************************************/
/*** EchoClient.java ***/
/*** ***/
/*****************************************************************************/
import java.io.*;
import java.net.*;
public class EchoClient
{
public static void main(String[] args)
{
try
{
Socket s = new Socket("my static ip address here", 3000);
BufferedReader r = new BufferedReader(new InputStreamReader(s.getInputStream()));
PrintWriter w = new PrintWriter(s.getOutputStream(), true);
BufferedReader con = new BufferedReader(new InputStreamReader(System.in));
String line;
do
{
line = r.readLine();
if ( line != null )
System.out.println(line);
line = con.readLine();
w.println(line);
}
while ( !line.trim().equals("bye") );
}
catch (Exception err)
{
System.err.println(err);
}
}
}
When i run it(both). The client program runs and it halts without any error. It just hangs.
当我运行它（两者）。客户端程序运行并停止，没有任何错误。它只是挂起。
I appreciate your help very much!
我非常感谢你的帮助！
回答by M S Parmar
Actually when your client code try to connect to server and send "string massage" to server at this time server read inputstream (by bufferreader) i.e. line = r.readLine(); // server code
实际上，当您的客户端代码尝试连接到服务器并向服务器发送“字符串消息”时，此时服务器读取输入流（通过 bufferreader）即 line = r.readLine(); // 服务器代码
here it would wait for \n or \r or \n\r (Line Feed, Carriage Return )at the end of String.
在这里它会在字符串的末尾等待 \n 或 \r 或 \n\r （换行，回车）。
so you need to append last character as \n or \r or \n\r both side while sending massage to server or vis-versa..
所以你需要在向服务器发送消息时将最后一个字符附加为 \n 或 \r 或 \n\r 。
.
.
.
do
{
line = r.readLine();
line = line +"\n"; // Add this line
if ( line != null )
System.out.println(line);
line = con.readLine();
w.println(line);
}
.
.
.
@Client code
@客户端代码
