所以我有一个java TCP服务器和客户端。客户端正在尝试将用户注册到服务器。我可以看到用户是从我的print语句添加到服务器上但我的客户端没有收到＆＃ 34;添加了用户，尝试登录＆＃34;消息。
服务器
class Server implements Runnable
{
Socket connectionSocket;
UserRepo userRepo;
public static final String COMMAND_SEPARATOR = "%%";
public Server(Socket s){
try{
System.out.println("Client Got Connected " );
connectionSocket=s;
userRepo = new UserRepo();
}catch(Exception e){e.printStackTrace();}
}
public void run(){
try{
String recievedMessage="";
BufferedReader reader =
new BufferedReader(new InputStreamReader(connectionSocket.getInputStream()));
BufferedWriter writer=
new BufferedWriter(new OutputStreamWriter(connectionSocket.getOutputStream()));
while(!recievedMessage.equalsIgnoreCase("exit")){
recievedMessage = reader.readLine().trim();
String [] components = recievedMessage.split(COMMAND_SEPARATOR);
if(components[0].equals("register")){
User user= userRepo.addUser(components[1], components[2]);
if(user==null){
writer.write("\r\n=== User wasnt added,"
+ "mayby there is already an account for that email? " );
writer.flush();
}else{
writer.write("\r\n=== User was added,try logging in");
System.out.println("user added");
writer.flush();
}
}
recievedMessage="";
recievedMessage = reader.readLine().trim();
}
connectionSocket.close();
}catch(Exception e){e.printStackTrace();}
}
public static void main(String argv[]) throws Exception
{
System.out.println("Threaded Server is Running " );
ServerSocket mysocket = new ServerSocket(5555);
while(true)
{
Socket sock = mysocket.accept();
Server server=new Server(sock);
Thread serverThread=new Thread(server);
serverThread.start();
}
}
}
客户端
import java.io.IOException;
import java.io.PrintWriter;
import java.net.Socket;
import java.util.Scanner;
import java.util.logging.Level;
import java.util.logging.Logger;
public class ClientShell {
public static final String COMMAND_SEPARATOR = "%%";
/**
* @param args the command line arguments
*/
public static void main(String[] args) {
try {
User loggedInUser = null;
String message = "";
String response = null;
Scanner keyboard = new Scanner(System.in);
// 1) Build data socket for client to use
Socket serverLink = new Socket("localhost", 5555);
// 2) Set up streams
// PrintWriter used for sending messages
PrintWriter output = new PrintWriter(serverLink.getOutputStream());
// Scanner / BufferedReader used for receiving messages
Scanner input = new Scanner(serverLink.getInputStream());
// 3) While we want still want to exchange messages
while(!message.equalsIgnoreCase("exit"))
{
while(loggedInUser==null){
notLoggedInOptions(keyboard,message,response,loggedInUser,output,input);
}
}
// 8) Close the link to the server (the data socket)
serverLink.close();
} catch (IOException ex) {
Logger.getLogger(ClientShell.class.getName()).log(Level.SEVERE, null, ex);
}
}
public static void notLoggedInOptions(Scanner keyboard,String message,String response,User loggedInUser,
PrintWriter output,Scanner input){
System.out.println("Type login for login or register for register");
message = keyboard.nextLine();
if(message.equalsIgnoreCase("login")){
}else if(message.equalsIgnoreCase("register")){
message="";
boolean validUserName = false;
while(validUserName == false){
System.out.println("Type the username you want as your prefix for your email");
System.out.println("It must be between 5 and 10 characters");
System.out.println("eg type mgraham if you want mgraham@danielhaughton@haughton.com");
message = keyboard.nextLine();
if(message.length()>4 && message.length()<11 == true){
validUserName = true;
}else{
System.out.println("It must be between 5 and 10 characters try again" );
}
}
String username = message;
message="";
boolean validPassword = false;
while(validPassword == false){
System.out.println("Type the password you want");
System.out.println("It must be atleast 8 characterrs");
message = keyboard.nextLine();
if(message.length()> 7){
validPassword = true;
}else{
System.out.println("It must be atleast 8 characterrs,try again");
}
}
String password = message;
System.out.println("username:" + username);
System.out.println("password:" + password);
output.println("register"+ COMMAND_SEPARATOR + username + COMMAND_SEPARATOR + password);
output.flush();
response = input.nextLine();
System.out.println(response);
}else{
System.out.println("Unsupported command!try again");
}
}
}
`
我在客户端上的输出
输入登录登录或注册登记
寄存器
输入您想要的用户名作为电子邮件的前缀
必须介于5到10个字符之间
例如，如果你想要mgraham @ danielhaughton @ haughton.com
，请输入mgraham丹尼尔
输入您想要的密码
必须至少8个字符
hello12345
用户名：丹尼尔
密码：hello12345
此处打印空行
输入登录登录或注册登记
答案 0 :(得分：0)
好吧，看看你的服务器发回的内容：
writer.write("\r\n=== User was added,try logging in");
因此，它会发送一个空行，然后是=== User was added,try logging in。因此，由于客户端读取下一行，并且接收到的下一行是空行，因此输出是您应该期望的。
如果您希望打印消息，则服务器应使用
writer.write("=== User was added,try logging in\r\n");
答案 1 :(得分：0)
您正在阅读线路，但您没有发送线路。每个发送的消息都需要一个行终止符。
注意：在执行任何其他代码之前，您必须检查readLine()的结果是否为空。