如何实现 ByteArrayOutputStream？

Question

我需要帮助来实现一个存储服务器输出的 byteArrayOutputStream，然后我可以从中读取和打印输出。有谁知道如何做到这一点？任何帮助将不胜感激。

TCPA问：

import java.net.*;
import java.io.*;
import tcpclient.TCPClient;

public class TCPAsk {
    /*
     * Usage: explain how to use the program, then exit with failure status
     */
    private static void usage() {
        System.err.println("Usage: TCPAsk host port <data to server>");
        System.exit(1);
    }

    /*
     * Main program. Parse arguments on command line and call TCPClient
     */
    public static void main( String[] args) {
        String hostname = null;
        int port = 0;
        byte[] userInputBytes = new byte[0];

        try {
            // Get mandatory command line arguments: hostname and port number
            int argindex = 0;
            hostname = args[argindex++];
            port = Integer.parseInt(args[argindex++]);

            // Remaining arguments, if any, are string to send to server
            if (argindex < args.length) {
                // Collect remaining arguments into a string with single space as separator
                StringBuilder builder = new StringBuilder();
                boolean first = true;
                while (argindex < args.length) {
                    if (first)
                        first = false;
                    else
                        builder.append(" ");
                    builder.append(args[argindex++]);
                }
                builder.append("\n");
                userInputBytes = builder.toString().getBytes();
            }
        } catch (ArrayIndexOutOfBoundsException | NumberFormatException ex) {
            // Exceeded array while parsing command line, or could
            // not convert port number argument to integer -- tell user
            // how to use the program
            usage();
        }

        try {
            TCPClient tcpClient = new tcpclient.TCPClient();
            byte[] serverBytes  = tcpClient.askServer(hostname, port, userInputBytes);
            String serverOutput = new String(serverBytes);
            System.out.printf("%s:%d says:\n%s", hostname, port, serverOutput);
        } catch(IOException ex) {
            System.err.println(ex);
            System.exit(1);
        }
    }
}

编辑：我的代码现在可以工作了，它与下面给出的答案 (TCPClient) 类似，只是做了一些小的补充。不需要 ByteArrayOutputStream。

Answer 1

您没有将用户数据发送到服务器。只需像这样修改 TCPClient：

package tcpclient;

import java.net.*;
import java.io.*;
import java.nio.charset.StandardCharsets;

public class TCPClient
{
    public TCPClient()
    {}

    public byte[] askServer(String hostname, int port, byte[] toServerBytes) throws IOException
    {
        Socket clientSocket = new Socket(hostname, port);

        byte[] bufferSize = new byte[1000];

        //send message to the server
        clientSocket.getOutputStream().write(toServerBytes);

        // Query response
        String response;
        // Length of response
        int responseLength;
        StringBuilder sb = new StringBuilder();

        while((responseLength = clientSocket.getInputStream().read(bufferSize)) != -1)
        {
            response = new String(bufferSize, 0, responseLength, StandardCharsets.UTF_8);
            sb.append(response);
        }

        clientSocket.close();
        return sb.toString().getBytes();
    }

如何实现 ByteArrayOutputStream？

how to implement ByteArrayOutputStream?

java

io

client-server

outputstream

bytearrayoutputstream