java - 从 Http Post 接收 UTF-8 响应

Question

我正在开发带有后端的 Android 应用程序，都是用 Java 编写的，并通过 Http Post 进行通信。当我发送包含非英语字符的请求时，后端可以很好地获取它们，但是当后端尝试返回非英语字符时，它们会收到“？”。假设我发送为 parmas "STR=שלום עולם" (希伯来语字符)

后端示例 servlet:

public class DebugServlet extends HttpServlet {
    @Override
    public void doPost(HttpServletRequest req, HttpServletResponse resp)
        throws IOException {

        String param = req.getParameter("STR");

        log(param); //Prints שלום עולם, So receiving fine!

        try(PrintWriter out = resp.getWriter()) {
            out.print(param);
        }
    }
}

客户端代码:

private final static String CHARSET = "UTF-8";
public static void send(String server, String servletName, Map<String, String> params){
    try{
        URL url = new URL(server + servletName);
        URLConnection connection = url.openConnection();

        HttpURLConnection conn = (HttpURLConnection) connection;

        OutputStream os;

        conn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded; charset=utf-8");
        conn.setRequestMethod("POST");
        conn.setUseCaches(false);
        conn.setDoInput(true);
        conn.setDoOutput(true);
        os = conn.getOutputStream();

        //Add parameters
        BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(os, CHARSET));
        StringBuilder paramsSB = new StringBuilder();
        boolean isFirst = true;
        for(Map.Entry<String,String> entry : params.entrySet()){
            if(isFirst)
                isFirst = false;
            else
                paramsSB.append("&");
            paramsSB.append(URLEncoder.encode(entry.getKey(), CHARSET));
            paramsSB.append("=");
            paramsSB.append(URLEncoder.encode(entry.getValue(), CHARSET));
        }

        writer.append(paramsSB.toString());

        writer.flush();
        writer.close();
        os.close();

        int responseCode;
        responseCode = conn.getResponseCode();

        if (responseCode != 200)
            throw new RuntimeException("...");

        StringBuilder chain = new StringBuilder("");
        try(BufferedReader rd = new BufferedReader(new InputStreamReader(conn.getInputStream()))) {
            String line = "";
            while ((line = rd.readLine()) != null) {
                chain.append(line);
            }
        }

        Log.d("MyTAG", chain.toString()); //Prints "???? ????", that's the problem
    } catch (IOException e) {
        // writing exception to log
        throw new RuntimeException("...");
    }
}

谢谢:)

Answer 1

您需要为 HttpServletResponse 设置响应编码 UTF-8。默认编码为 ISO_8859_1

    // response.setContentType("text/plain");
    response.setCharacterEncoding("UTF-8";

    // Write utf-8 strings