如何通过Java Web Server在浏览器中显示图像/ gif

Question

我有一个简单的Java Web Server，我正尝试使用它在浏览器中显示图像。

到目前为止，我拥有它，以便在进入localhost：7500 / image2.jpg时，它下载图像而不是在浏览器中显示它

转到gif扩展名（localhost：7500 / image33.gif）时，它只会显示一个很小的黑色正方形。

这是我到目前为止所做的：

    public void getType(File f, String path, BufferedReader bfr)
    {
        String extention = path.substring(path.lastIndexOf("/") + 1);
        try {
        if (extention == "gif")
        {
            String line;
            String httpResponse = "HTTP/1.1";
            httpResponse += " 200 OK \n";
            httpResponse += "Content-Type: image/gif\n" ;
            httpResponse += "Content-Length: " + f.length()+"\n\n";

            serverClient.getOutputStream().write(httpResponse.getBytes("UTF-8"));

            //loop to print each line of file to browser
            while ((line = bfr.readLine()) != null) 
            {
                serverClient.getOutputStream().write(line.getBytes("UTF-8"));
            }
        }
        else if (extention == "jpg")
        {
            String line;
            String httpResponse = "HTTP/1.1";
            httpResponse += " 200 OK \n";
            httpResponse += "Content-Type: image/jpg\n" ;
            httpResponse += "Content-Length: " + f.length()+"\n\n";

            serverClient.getOutputStream().write(httpResponse.getBytes("UTF-8"));

            //loop to print each line of file to browser
            while ((line = bfr.readLine()) != null) 
            {
                serverClient.getOutputStream().write(line.getBytes("UTF-8"));
            }

        }
        else
        {
            String line;
            String httpResponse = "HTTP/1.1 200 OK\r\n\r\n";
            serverClient.getOutputStream().write(httpResponse.getBytes("UTF-8"));

            //loop to print each line of file to browser
            while ((line = bfr.readLine()) != null) 
            {
                serverClient.getOutputStream().write(line.getBytes("UTF-8"));
            }
        }
    }catch(Exception ex)
      {
      //when page is loaded, print confirmation to system
      System.out.println("999999999");
      }

    }

Answer 1

您似乎正在用byte-> char-> byte逐行复制为UTF-8字节来处理JPG / GIF文件。相反，您应该将GIF / JPG作为InputStream打开，并且将它们直接写入servlet输出流中而不进行更改。在JPG / GIF块中，您需要替换bfr上的while循环以传递图像而无需进行任何转换：

Files.copy(f.toPath(), serverClient.getOutputStream());

在最后一块，您需要确定哪种字符集适合于要返回的内容。可以按原样使用阅读器，也可以按上述内容以流方式传递，这取决于内容。