java - 通过套接字读取 JPEG 流给出空字符

Question

我正在使用此代码通过 InputStream 读取 .jpg 文件，但我在一些文本后收到 NULNUL...n 流。我正在阅读此文件 link to file以及我收到的文件的链接，链接是 Written File link 。

    while ((ret = input.read(imageCharArray)) != -1) {
    packet.append(new String(imageCharArray, 0, ret));

    totRead += ret;
            imageCharArray = new char[4096];
       }


   file = new File(
     Environment.getExternalStorageDirectory()
       + "/FileName_/"
       + m_httpParser.filename + ".jpg");
   PrintWriter printWriter = new PrintWriter(file);
   // outputStream = new FileOutputStream(file);  //also Used FileoutputStream for writting
   // outputStream.write(packet.toString().getBytes());//
   // ,
   printWriter.write(packet.toString());
   // outputStream.close();
   printWriter.close();
 }

我也尝试过FileoutputStream，但也对此进行了hardlucj，正如我的代码中所评论的那样。

编辑 我也用过这个。我有一个内容长度字段，我正在读取和写入该字段

    byte[] bytes = new byte[1024];
int totalReadLength = 0;

// read untill we have bytes
while ((read = inputStream.read(bytes)) != -1
        && contentLength >= (totalReadLength)) {

    outputStream.write(bytes, 0, read);
    totalReadLength += read;
    System.out.println(" read size ======= "
            + read + " totalReadLength = "
            + totalReadLength);

}

Answer 1

String 不是二进制数据的容器，PrintWriter 也不是写入它的方法。摆脱所有、所有、字节和字符串之间的转换，反之亦然，只用输入和输出流传输字节:

while ((count = in.read(buffer)) > 0)
{
    out.write(buffer, 0, count);
}

如果您需要限制从输入读取的字节数，则必须在调用 read() 之前执行此操作，并且还必须正确限制 read():

while (total < length && (count = in.read(buffer, 0, length-total > buffer.length ? buffer.length: (int)(length-total))) > 0)
{
    total += count;
    out.write(buffer, 0, count);
}