在建立http请求的时候，一定要注意请求格式：

public static JSONObject httpRequest(String requestUrl, String requestMethod, String outputStr) {
    JSONObject jsonObject = null;
StringBuffer buffer = new StringBuffer();
    try {

        URL url = new URL(requestUrl);
        //注意这边是https的请求，所以在发送请求的时候，也必须是https的，如果是http的请求，就会出现问题
HttpsURLConnection httpUrlConn = (HttpsURLConnection) url.openConnection();

httpUrlConn.setDoOutput(true);
httpUrlConn.setDoInput(true);
httpUrlConn.setUseCaches(false);
// 设置请求方式（GET/POST）
httpUrlConn.setRequestMethod(requestMethod);

        if ("GET".equalsIgnoreCase(requestMethod)) {
            httpUrlConn.connect();
}

        // 当有数据需要提交时
if (null != outputStr) {
            OutputStream outputStream = httpUrlConn.getOutputStream();
// 注意编码格式，防止中文乱码
outputStream.write(outputStr.getBytes("UTF-8"));
outputStream.close();
}

        // 将返回的输入流转换成字符串
InputStream inputStream = httpUrlConn.getInputStream();
InputStreamReader inputStreamReader = new InputStreamReader(inputStream, "UTF-8");
BufferedReader bufferedReader = new BufferedReader(inputStreamReader);

String str = null;
        while ((str = bufferedReader.readLine()) != null) {
            buffer.append(str);
}
        bufferedReader.close();
inputStreamReader.close();
// 释放资源
inputStream.close();
inputStream = null;
httpUrlConn.disconnect();
jsonObject = JSONObject.fromObject(buffer.toString());
} catch (ConnectException ce) {
        log.error("Weixin server connection timed out.");
} catch (Exception e) {
        log.error("https request error:{}", e);
}
    return jsonObject;
}

如果http和https不匹配会出现以下异常：

javax.net.ssl.SSLException: Unsupported or unrecognized SSL message

public static JSONObject httpRequest(String requestUrl, String requestMethod, String outputStr) {
    JSONObject jsonObject = null;
StringBuffer buffer = new StringBuffer();
    try {

        URL url = new URL(requestUrl);
HttpsURLConnection httpUrlConn = (HttpsURLConnection) url.openConnection();

httpUrlConn.setDoOutput(true);
httpUrlConn.setDoInput(true);
httpUrlConn.setUseCaches(false);
// 设置请求方式（GET/POST）
httpUrlConn.setRequestMethod(requestMethod);

        if ("GET".equalsIgnoreCase(requestMethod)) {
            httpUrlConn.connect();
}

        // 当有数据需要提交时
if (null != outputStr) {
            OutputStream outputStream = httpUrlConn.getOutputStream();
// 注意编码格式，防止中文乱码
outputStream.write(outputStr.getBytes("UTF-8"));
outputStream.close();
}

        // 将返回的输入流转换成字符串
InputStream inputStream = httpUrlConn.getInputStream();
InputStreamReader inputStreamReader = new InputStreamReader(inputStream, "UTF-8");
BufferedReader bufferedReader = new BufferedReader(inputStreamReader);

String str = null;
        while ((str = bufferedReader.readLine()) != null) {
            buffer.append(str);
}
        bufferedReader.close();
inputStreamReader.close();
// 释放资源
inputStream.close();
inputStream = null;
httpUrlConn.disconnect();
jsonObject = JSONObject.fromObject(buffer.toString());
} catch (ConnectException ce) {
        log.error("Weixin server connection timed out.");
} catch (Exception e) {
        log.error("https request error:{}", e);
}
    return jsonObject;
}