我正在尝试学习如何在下学期之前使用Java套接字。我写了这个程序，它应该接受来自发件人的邮件并将邮件发送给收件人。您可以通过写入已连接的客户端的名称来指定接收方，如果客户端未连接，则服务器将通过发送消息“DISCONNECTED”进行响应。但由于某种原因，邮件不会发送给收件人。我仍然可以将消息发送给发件人。这是寻求这种帮助的正确论坛吗？
这是我的客户端类
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.Socket;
public class MyTestClient {
static int port = 0;
static String ip = "";
static String name = "";
public static void main(String args[] ) {
if(args.length == 3) {
try{
port = Integer.parseInt(args[1]);
} catch(NumberFormatException e) {
System.out.println("Usage: Java MyTestClient <ip> <port> <name>");
System.exit(0);
}
ip = args[0];
name = args[2];
} else {
System.out.println("Usage: Java MyTestClient <ip> <port> <name>");
System.exit(0);
}
try {
Socket socket = new Socket(ip, port);
new Thread(new MessageHandler(socket)).start();
new Thread(new InputHandler(socket)).start();
} catch (IOException e) {
System.out.println("Could not connect to: " + ip + " : " + port);
System.exit(0);
}
}
public static class MessageHandler implements Runnable {
Socket socket;
public MessageHandler(Socket socket) {
this.socket = socket;
}
@Override
public void run() {
PrintWriter out = null;
BufferedReader in = null;
try {
out = new PrintWriter(socket.getOutputStream(), true);
in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
}catch(IOException e) {
e.printStackTrace();
}
String fromServer;
try {
while ((fromServer = in.readLine()) != null) {
System.out.println(fromServer);
fromServer.trim();
if(fromServer.contains(" ")) {
String split[] = fromServer.split(" ", 2);
System.out.println(split.length == 2 ? split[1] + " Is a two part message" : "Strange message");
} else {
if(fromServer.equals("NAME")) {
System.out.println("Server asks for name | gives given name to server");
out.println(name);
}
if(fromServer.equals("SUCCESS")) {
System.out.println("Message succesfully sent");
}
if(fromServer.equals("ERROR")) {
System.out.println("Something went wrong when sending the message");
}
if(fromServer.equals("OCCUPIED")) {
System.out.println("Name was already used. Start the program with another name");
socket.close();
System.exit(0);
}
if(fromServer.equals("DISCONNECTED")) {
System.out.println("The reciever was not connected");
}
if(fromServer.equals("REGISTERED")) {
System.out.println("Successfully logged in to server");
}
}
}
} catch(IOException e) {
e.printStackTrace();
}
}
}
public static class InputHandler implements Runnable {
Socket socket;
public InputHandler(Socket socket) {
this.socket = socket;
}
@Override
public void run() {
String fromUser = null;
PrintWriter out = null;
try {
out = new PrintWriter(socket.getOutputStream(), true);
} catch (IOException e) {
e.printStackTrace();
}
BufferedReader kbi = new BufferedReader(new InputStreamReader(System.in));
try {
while ((fromUser = kbi.readLine()) != null) {
out.println(fromUser);
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
这是我的服务器类
import java.io.*;
import java.net.*;
import java.util.*;
public class MyServer {
public static int port;
public static int maxConnections;
public static final String NAME = "Server";
private static Map<String, Socket> socketsMap = new HashMap<>();
public static void main(String args[]) {
if(args.length == 2) {
try{
port = Integer.parseInt(args[0]);
maxConnections = Integer.parseInt(args[1]);
}catch(Exception e){
System.out.println("Usage: Java Myserver <port> <maxConnections>");
System.exit(0);
}
} else {
System.out.println("Usage: Java Myserver <port> <maxConnections>");
System.exit(0);
}
new Thread(new ConnectionHandler(port, maxConnections)).start();
}
public static class ConnectionHandler implements Runnable {
private ServerSocket server;
private Socket socket = null;
public int currentSocket = 0;
public int port = 0;
public int maxConnections = 0;
public ConnectionHandler(int port, int maxConnections) {
this.maxConnections = maxConnections;
this.port = port;
}
@Override
public void run() {
try {
server = new ServerSocket(7777);
} catch (IOException e1) {
System.out.println("Server could not connect to port: " + port);
e1.printStackTrace();
System.exit(0);
}
while(currentSocket++ < maxConnections) {
try {
socket = server.accept();
PrintWriter out = new PrintWriter(socket.getOutputStream(), true);
BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
out.println("NAME");
String message;
while((message = in.readLine()) != null) {
if(!socketsMap.containsKey(message) || message.equals("SERVER")) {
out.println("REGISTERED");
socketsMap.put(message, socket);
System.out.println(message + " has logged on server");
new Thread(new SocketHandler(socketsMap.get(message))).start();
} else {
out.println("OCCUPIED");
System.out.println(socket.getInetAddress().toString() + " has tried to login with existing name " + message);
socket.close();
currentSocket--;
}
socket = null;
break;
}
} catch (IOException e) {
System.out.println("Something went wrong with client connection");
}
}
}
}
public static class SocketHandler implements Runnable {
Socket socket = null;
public SocketHandler(Socket socket) {
this.socket = socket;
}
@Override
public void run() {
try {
BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
PrintWriter respond = new PrintWriter(socket.getOutputStream(), true);
String input;
while((input = in.readLine() ) != null) {
String[] info = input.split(" ", 2);
if(info.length != 2){
System.out.println("Message computed wrong");
respond.println("ERROR");
break;
}
if(info[0].equals("SERVER")) {
//TODO: Write a server command handler class
} else if ( socketsMap.containsKey(info[0]) ){
Socket reciever = socketsMap.get(info[0]);
PrintWriter out = new PrintWriter(reciever.getOutputStream());
respond.println("SUCCESS");
System.out.println(info[0] + " send the message: "+ info[1]);
out.println("MESSAGE" + " " + info[1]);
break;
} else {
System.out.println("Reciever is not connected");
respond.println("DISCONNECTED");
}
}
}catch(IOException e) {
e.printStackTrace();
}
}
}
}
也许你可以在电脑上运行它，看看我的意思？
答案 0 :(得分：-1)
@Override
public void run() {
try {
server = new ServerSocket(7777);
} catch (IOException e1) {
System.out.println("Server could not connect to port: " + port);
e1.printStackTrace();
System.exit(0);
}
将上面的代码更改为
@Override
public void run() {
try {
server = new ServerSocket(port);
} catch (IOException e1) {
System.out.println("Server could not connect to port: " + port);
e1.printStackTrace();
System.exit(0);
}