如何在JAVA中创建HTTP响应发送图像? [英] How to create a HTTP-response sending an image in JAVA?

问题描述

我在用JAVA编写基本的Web服务器时遇到了一些麻烦.目前，它在传递html或css文件方面运行良好.但是，当涉及到图像时，事情就变得混乱了.我认为读取图像文件并准备将其发送时做错了事.但是看一下代码:

I'm occurring some trouble writing a basic webserver in JAVA. It's currently working fine at delivering html or css files. But when it comes to images things are messed up. I assume I'm doing something wrong at reading the image-files and preparing them to be sent. But have a look at the code:

public void launch()
{
    while(true)
    {
        try
        {
             Socket connection = this.server_socket.accept();

             ...

             PrintWriter print_writer = new PrintWriter(connection.getOutputStream());

             String response = this.readFile(this.request_header.get("Resource"));
             print_writer.print(response);

             print_writer.flush();
             connection.close();
         }
         catch(...)
         {
             ...
         }
    }
}

private String readFile(String path)
{
    try
    {
         ...

         FileInputStream file_input_stream = new FileInputStream(path);         
         int bytes = file_input_stream.available();
         byte[] response_body = new byte[bytes];

         file_input_stream.read(response_body);
         this.response_body = new String(response_body);

         file_input_stream.close();

         this.setResponseHeader(200, file_ext);

         this.response_header = this.response_header + "\r\n\r\n" + this.response_body;
    }
    catch(...)
    {
         ...
    }

    return this.response_header;
}

所以我的浏览器收到类似以下内容的信

So my browser receives something like:

HTTP/1.0 200 OK
Content-type: image/jpeg

[String that was read in readFile()]

但是chrome无法正确显示图像，而歌剧也无法全部显示！我曾经使用BufferedReader读取文件，但发现有人说BufferedReader无法正确处理二进制数据，因此我尝试使用FileInputStream，但问题仍然相同):

But chrome's not displaying the image correctly and opera won't show it all! I used to read the file with an BufferedReader but I found someone saying that the BufferedReader can't handle binary data properly so I tried with the FileInputStream, but the problem stayed the same ):

谢谢您的任何提示和帮助(:

Thanks for any hints and help in advance (:

推荐答案

您必须同时使用流:输入流和输出流.读者和作家假定内容为Unicode，并对字节流进行调整.当然，PrintWriter是作家.

You must use streams on both sides: input stream and output stream. Readers and writers assume the content is Unicode and make adjustments to the byte stream. PrintWriter is, of course, a writer.

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