如何解决ChatClient.java中的readLine（）弃用警告？

Question

我试图创建一个聊天客户端/服务器网络，我认为它对服务器来说工作正常，但客户端有一些问题，因为它有一个弃用的警告，然后我程序告诉我使用该标志 - Xlint，我跑的javac -Xlint：弃用ChatClient，但我不知道怎样做才能修复这个警告声明：

ChatClient.java:47：警告：[折旧]的readLine（）在DataInputStream所已弃用 流输出.writeUTF（到Console.ReadLine（））;

这是我ChatClient.java文件

import java.net.*; 
import java.io.*; 


public class ChatClient implements Runnable 
{ 
    private Socket socket    = null; 
    private Thread thread    = null; 
    private DataInputStream console = null; 
    private DataOutputStream streamOut = null; 
    private ChatClientThread client = null; 

public ChatClient(String serverName, int serverPort) 
{ 
    System.out.println("Establishing connection to server..."); 

    try 
    { 
     // Establishes connection with server (name and port) 
     socket = new Socket(serverName, serverPort); 
     System.out.println("Connected to server: " + socket); 
     start(); 
    } 

    catch(UnknownHostException uhe) 
    { 
     // Host unkwnown 
     System.out.println("Error establishing connection - host unknown: " + uhe.getMessage()); 
    } 

    catch(IOException ioexception) 
    { 
     // Other error establishing connection 
     System.out.println("Error establishing connection - unexpected exception: " + ioexception.getMessage()); 
    } 

} 

public void run() 
{ 
    while (thread != null){ 
     try 
     { 
      // Sends message from console to server 
      streamOut.writeUTF(console.readLine()); 
      streamOut.flush(); 
     } 

     catch(IOException ioexception) 
     { 
      System.out.println("Error sending string to server: " + ioexception.getMessage()); 
      stop(); 
     } 
    } 
} 


public void handle(String msg) 
{ 
    // Receives message from server 
    if (msg.equals(".quit")) 
    { 
     // Leaving, quit command 
     System.out.println("Exiting...Please press RETURN to exit ..."); 
     stop(); 
    } 
    else 
     // else, writes message received from server to console 
     System.out.println(msg); 
} 

// Inits new client thread 
public void start() throws IOException 
{ 
    console = new DataInputStream(System.in); 
    streamOut = new DataOutputStream(socket.getOutputStream()); 
    if (thread == null) 
    { 
     client = new ChatClientThread(this, socket); 
     thread = new Thread(this);     
     thread.start(); 
    } 
} 

// Stops client thread 
public void stop() 
{ 
    if (thread != null) 
    { 
     thread.stop(); 
     thread = null; 
    } 
    try 
    { 
     if (console != null) console.close(); 
     if (streamOut != null) streamOut.close(); 
     if (socket != null) socket.close(); 
    } 

    catch(IOException ioe) 
    { 
     System.out.println("Error closing thread..."); } 
     client.close(); 
     client.stop(); 
    } 


public static void main(String args[]) 
{ 
    ChatClient client = null; 
    if (args.length != 2) 
     // Displays correct usage syntax on stdout 
     System.out.println("Usage: java ChatClient host port"); 
    else 
     // Calls new client 
     client = new ChatClient(args[0], Integer.parseInt(args[1])); 
} 

} 

class ChatClientThread extends Thread 
{ 
    private Socket   socket = null; 
    private ChatClient  client = null; 
    private DataInputStream streamIn = null; 

public ChatClientThread(ChatClient _client, Socket _socket) 
{ 
    client = _client; 
    socket = _socket; 
    open(); 
    start(); 
} 

public void open() 
{ 
    try 
    { 
     streamIn = new DataInputStream(socket.getInputStream()); 
    } 
    catch(IOException ioe) 
    { 
     System.out.println("Error getting input stream: " + ioe); 
     client.stop(); 
    } 
} 

public void close() 
{ 
    try 
    { 
     if (streamIn != null) streamIn.close(); 
    } 

    catch(IOException ioe) 
    { 
     System.out.println("Error closing input stream: " + ioe); 
    } 
} 

public void run() 
{ 
    while (true) 
    { try 
     { 
      client.handle(streamIn.readUTF()); 
     } 
     catch(IOException ioe) 
     { 
      System.out.println("Listening error: " + ioe.getMessage()); 
      client.stop(); 
     } 
    } 
} 
} 

我认为这个问题是使用.readLine（），但我需要帮助解决这个问题。

Answer 1

您可以将@SuppressWarnings("deprecation")注释添加到您的类或方法来抑制警告。弃用通常意味着方法或类将在下一个主要版本中删除，但为了向后兼容，已保留在当前版本中。通常如果注释为@Deprecated，这是因为已经编写了一个新的方法或类，它以更简洁的方式执行相同的任务，所以我不一定建议仅仅添加@SuppressWarnings注释，而是查看以正确的方式读取行您正在使用的Java版本。

Answer 2

这里的概念问题是DataInputStream不是一个用于处理文本的API。 readLine方法对流的字符编码方案具有硬连接假设。

从System.in线路输入的一种更好的方式将其包装成一个BufferedReader和使用BufferedReader.readLine()。

如果您忽略该问题（例如使用@SuppressWarning），则可能会发现如果控制台配置为使用某些字符编码，则应用程序会损坏字符。例如，我怀疑UTF-8会中断。