问题
我正在尝试实现TCP连接,从服务器端一切正常,但是当我运行客户端程序(从客户端计算机)时,我收到以下错误:
java.net.ConnectException: Connection refused
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:351)
at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:213)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:200)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:432)
at java.net.Socket.connect(Socket.java:529)
at java.net.Socket.connect(Socket.java:478)
at java.net.Socket.<init>(Socket.java:375)
at java.net.Socket.<init>(Socket.java:189)
at TCPClient.main(TCPClient.java:13)
我尝试更改套接字号以防它正在使用但无济于事,是否有人知道是什么导致此错误以及如何解决它。
服务器代码:
//TCPServer.java
import java.io.*;
import java.net.*;
class TCPServer {
public static void main(String argv[]) throws Exception {
String fromclient;
String toclient;
ServerSocket Server = new ServerSocket(5000);
System.out.println("TCPServer Waiting for client on port 5000");
while (true) {
Socket connected = Server.accept();
System.out.println(" THE CLIENT" + " " + connected.getInetAddress()
+ ":" + connected.getPort() + " IS CONNECTED ");
BufferedReader inFromUser = new BufferedReader(
new InputStreamReader(System.in));
BufferedReader inFromClient = new BufferedReader(
new InputStreamReader(connected.getInputStream()));
PrintWriter outToClient = new PrintWriter(
connected.getOutputStream(), true);
while (true) {
System.out.println("SEND(Type Q or q to Quit):");
toclient = inFromUser.readLine();
if (toclient.equals("q") || toclient.equals("Q")) {
outToClient.println(toclient);
connected.close();
break;
} else {
outToClient.println(toclient);
}
fromclient = inFromClient.readLine();
if (fromclient.equals("q") || fromclient.equals("Q")) {
connected.close();
break;
} else {
System.out.println("RECIEVED:" + fromclient);
}
}
}
}
}
客户代码:
//TCPClient.java
import java.io.*;
import java.net.*;
class TCPClient {
public static void main(String argv[]) throws Exception {
String FromServer;
String ToServer;
Socket clientSocket = new Socket("localhost", 5000);
BufferedReader inFromUser = new BufferedReader(new InputStreamReader(
System.in));
PrintWriter outToServer = new PrintWriter(
clientSocket.getOutputStream(), true);
BufferedReader inFromServer = new BufferedReader(new InputStreamReader(
clientSocket.getInputStream()));
while (true) {
FromServer = inFromServer.readLine();
if (FromServer.equals("q") || FromServer.equals("Q")) {
clientSocket.close();
break;
} else {
System.out.println("RECIEVED:" + FromServer);
System.out.println("SEND(Type Q or q to Quit):");
ToServer = inFromUser.readLine();
if (ToServer.equals("Q") || ToServer.equals("q")) {
outToServer.println(ToServer);
clientSocket.close();
break;
} else {
outToServer.println(ToServer);
}
}
}
}
}
#1 热门回答(245 赞)
此异常表示没有服务侦听你尝试连接的IP /端口:
- 你正在尝试连接到错误的IP /端口。
- 你尚未启动服务器。
- 你的服务器没有侦听连接。
- 在Windows服务器上,侦听backlog队列已满。
#2 热门回答(31 赞)
我会检查:
- 你尝试连接的主机名和端口
- 服务器端已成功开始正确监听
- 没有防火墙阻止连接
最简单的起点可能是尝试使用telnet或Putty从客户端计算机手动连接。如果成功,则问题出在你的客户端代码中。如果没有,你需要工作,不能没有.Wireshark可以帮助你在这方面。
#3 热门回答(4 赞)
你必须将客户端套接字连接到远程ServerSocket。代替Socket clientSocket = new Socket("localhost", 5000);
做Socket clientSocket = new Socket(serverName, 5000);
客户端必须连接到serverName,该名称应与实例化你的ServerSocket
的框的名称或IP匹配(名称必须可从客户端计算机访问)。顺便说一句:这不是重要的名字,而是关于IP地址......