java 。从 BufferedInputStream 读取并写入 FileOutputStream

Question

我正在尝试用java编写客户端和服务器端。服务器端正常(在多个客户端上检查)。

所以，问题出在客户端。我为 bytearray 分配内存，从 BufferedInputStream 读取并写入该 bytearray。然后从bytearray写入FileOutputStream。一切正常，但 bytearray 的可用空间被 NULL 填充，因此接收到的文件不正确(例如图像)。

我发现了该问题的 2 个决定:

1. 读取bytearray直到文件末尾(但我不知道文件末尾在哪里)
2. 从BufferedInputStream读取到FileInputStream，但不起作用:

我实际上需要接收 header 和文件。将 header 输出到控制台并将文件写入光盘。

完整来源

public class SClient {
private static int bufferSize = 8192;
/**
 * @param args the command line arguments
 */
public static void main(String[] args) {
    System.out.println("Enter the address:");
    BufferedReader bufferRead = new BufferedReader
                (new InputStreamReader(System.in));

    try {
        String address = bufferRead.readLine();
        System.out.println("Enter the extention of receiving file:");
        String fileExt = bufferRead.readLine();
        // TODO code application logic here
        Socket socket = new Socket(address,4040);
        BufferedInputStream bis = new BufferedInputStream
                (socket.getInputStream());

        BufferedOutputStream bout = new BufferedOutputStream
                (socket.getOutputStream());
        System.out.println("Enter the request:");
        String message = bufferRead.readLine();// GET /index.html HTTP/1.0

        System.out.println("Header read");
        if(message!=null){
            bout.write(message.getBytes());
        }
        FileOutputStream fout = new FileOutputStream("out"+fileExt);
        String s1 = "\r\n\r\n";
        bout.write(s1.getBytes());
        bout.flush();
        System.out.println("Header sent");

        byte[] res = new byte[bufferSize];
        int got;
        while((got = bis.read(res))!=-1){
            fout.write(res,0,got);
        }
        fout.close();
        bout.flush();
        socket.close();
    } catch (Exception e) {
        e.printStackTrace();
    }
  }
}

服务器端源码:

    String endLine = "\r\n";
    File f = new File(fileName);
    FileInputStream fstream;
    fstream = new FileInputStream(f);
    response = "HTTP/1.0 200 OK" + endLine;
    header = "Content-type: "+ contentType + endLine + "Content-length: " + f.length() + endLine + endLine;
    bout.write(response.getBytes());
    bout.write(header.getBytes());
    while(fstream.read(buffer) != -1) {
        bout.write(buffer);
    }
    System.out.println("Message sent");
    bout.flush();
    socket.close();

Answer 1

您必须记住读入缓冲区的字节数，并且只能将这些字节写回。像这样:

int got;
while ((got = bis.read(res)) != -1) {

    fout.write(res, 0, got);
}