socket通信为什么获取不到流里面的数据

Question

就是我在用while循环读取数据的时候读不出来？但是我打印new String(buf).trim()就有数据？
我们后台是.net写的。请问这是个什么问题
package com.jm.jmsdk_tools_jar;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.net.ConnectException;
import java.net.InetSocketAddress;
import java.net.Socket;
import java.net.SocketTimeoutException;

public class Socketest {

public synchronized static String sendMsg(String host, int port, String msg) {
    // 写
    String result = null;
    InputStream is = null;
    OutputStreamWriter osw = null;
    BufferedReader reader = null;
    Socket socket = new Socket();

    try {
        if (port < 0) {
            return "";
        }
        InetSocketAddress isa = new InetSocketAddress(host, port);
        socket.connect(isa, 10000);
        osw = new OutputStreamWriter(socket.getOutputStream());
        BufferedWriter writer = new BufferedWriter(osw);
        writer.write(msg);
        writer.flush();
        StringBuffer sb = new StringBuffer();
        reader = new BufferedReader(new InputStreamReader(socket.getInputStream()));
        System.out.println("reader:"+reader);
        int len = 0;
        char[] buf = new char[1024];
        while ((len = reader.read(buf)) != -1) {

            sb.append(buf, 0, len);

            System.out.println(new String(buf).trim());

        }

        result = sb.toString();

        System.out.println("result:" + result);
    } catch (SocketTimeoutException e) {
        e.printStackTrace();
        return null;
    } catch (ConnectException e) {
        return null;
    } catch (Exception e) {
        e.printStackTrace();
        return null;
    } finally {
        try {
            if (reader != null)
                try {
                    reader.close();
                } catch (Exception e) {
                }
            closeOutputStreamWriter(osw);
            closeInputStream(is);
            closeSocket(socket);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    return result;
}

private static void closeOutputStreamWriter(OutputStreamWriter osw) throws IOException {
    if (osw != null) {
        osw.close();
    }
}

private static void closeInputStream(InputStream is) throws IOException {
    if (is != null) {
        is.close();
    }
}

private static void closeSocket(Socket socket) throws IOException {
    if (socket != null) {
        socket.close();
    }
}

public static String streamToString(InputStream is) {
    try {
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        byte[] buffer = new byte[1024];
        int len = 0;
        while ((len = is.read(buffer)) != -1) {
            baos.write(buffer, 0, len);
        }
        baos.close();
        is.close();
        byte[] byteArray = baos.toByteArray();
        return new String(byteArray);
    } catch (Exception e) {
        return null;
    }
}

}

Answer 1

问题问的不清楚，“while循环读取数据的时候读不出来”是什么意思？在哪一行？