java - 如何保证java POST请求字符串/文本是UTF-8编码

Question

我有一条短信/字符串，其中包含 ä、ü、ß 等字母。我希望所有内容都采用 UTF-8 编码。当我写入文件或将字符串打印到控制台时，一切都很好。但是，当我想将相同的字符串发送到 Web 服务时，我得到的不是 ä,ü,ß，而是以下 �
我从 Servlet 读取该文件。 我真的必须使用以下 2 行来获取 UTF-8 编码的文本吗？

byte [] bray = text.getBytes("UTF-8");
                text = new String(bray);

.

public static String readAsStream_UTF8(String filePathName){
        String text ="";
        InputStream input = Thread.currentThread().getContextClassLoader().getResourceAsStream("resources/"+filePathName);
        if(input == null){          
            System.out.println("Inputstream null.");            
        }else{          
            InputStreamReader isr = null;
            try {               
                isr = new InputStreamReader((InputStream)input, "UTF-8");
                BufferedReader reader = new BufferedReader(isr);
                StringBuilder sb = new StringBuilder();
                String sCurrentLine;
                while ((sCurrentLine = reader.readLine()) != null) {
                    sb.append(sCurrentLine);                                
                }       
                text= sb.toString();        

                //it works only if I use the following 2 lines
                byte [] bray = text.getBytes("UTF-8");
                text = new String(bray);

            } catch (Exception e1) { 
                e1.printStackTrace();
            }           
        }               
        return text;
    }

我的 sendPOST 方法如下所示:

String charset = "UTF-8";
OutputStreamWriter writer = null;
HttpURLConnection con = null;
String response_txt ="";
InputStream iss = null;

try {

    URL url = new URL(urlService);
    con = (HttpURLConnection)url.openConnection();
    con.setDoOutput(true); //triggers POST
    con.setDoInput(true);
    con.setRequestMethod("POST");
    con.setRequestProperty("accept-charset", charset);
    //con.setRequestProperty("Content-Type", "application/soap+xml");
    con.setRequestProperty("Content-Type", "application/soap+xml;charset=UTF-8");


    writer = new OutputStreamWriter(con.getOutputStream());
    writer.write(msg); //send POST data string      
    writer.flush();
    writer.close();

我需要做什么才能强制将发送到 Web 服务的消息真正采用 UTF-8 编码。

Answer 1

如果您知道要发送的文件的编码，则无需将其转换为中间字符串。只需将其字节复制到输出即可:

// inputstream to a UTF-8 encoded resource file
InputStream in = Thread.currentThread().getContextClassLoader().getResourceAsStream("resources/"+filePathName);

HttpURLConnection con = ...

// set contenttype and encoding
con.setRequestProperty("Content-Type", "application/soap+xml;charset=UTF-8");
// copy input to output
copy(in, con.getOutputStream()); 

使用一些copy功能。

此外，您还可以将 Content-Length header 设置为资源文件的大小。