Java 无法将post请求更改为put请求

我为我的HTTP请求编写了一个类。 我的问题是，尽管在这段代码的几行中我添加了：

httpConn.setRequestMethod("PUT");

我的代码仍然执行POST请求而不是PUT请求！我错了什么？谢谢

public MultipartUtility(String requestURL, String charset)
            throws IOException {
        this.charset = charset;

        // creates a unique boundary based on time stamp
        boundary = "===" + System.currentTimeMillis() + "===";

        URL url = new URL(requestURL);
        httpConn = (HttpURLConnection) url.openConnection();
        httpConn.setUseCaches(false);
        httpConn.setRequestMethod("PUT");
        httpConn.setDoOutput(true); // indicates POST method
        httpConn.setRequestMethod("PUT");
        httpConn.setDoInput(true);

        httpConn.setRequestProperty("Content-Type",
                "multipart/form-data; boundary=" + boundary);
        httpConn.setRequestProperty("User-Agent", "CodeJava Agent");
        httpConn.setRequestProperty("Test", "Bonjour");
        outputStream = httpConn.getOutputStream();
        writer = new PrintWriter(new OutputStreamWriter(outputStream, charset),
                true);
    }

---

httpConn.setUseCaches（false）可以影响此结果。我不确定
PUT
能否提供此功能
httpConn.setUseCaches（false）；可以影响这个结果。我不确定PUT能否提供这一点feature@Adem你是对的！请写一个答案，这样我就可以给它打分了！谢谢