微信接口 请求 编码 utf-8 相关设置

public static String sendPost(String url, String param) {
        PrintWriter out = null;
        BufferedReader in = null;
        String result = "";
        try {
            URL realUrl = new URL(url);
            // 打开和URL之间的连接
            URLConnection conn = realUrl.openConnection(); 

            // 发送POST请求必须设置如下两行
            conn.setDoOutput(true);
            conn.setDoInput(true);
            // 获取URLConnection对象对应的输出流           
            byte[] requestStringBytes = param.getBytes("UTF-8"); 
           
            conn.setRequestProperty("Content-length", "" + requestStringBytes.length);  
            conn.setRequestProperty("Content-Type", "application/octet-stream");  
            conn.setRequestProperty("Connection", "Keep-Alive");// 维持长连接  
            conn.setRequestProperty("Charset", "UTF-8");

            OutputStream outputStream = conn.getOutputStream();  
            outputStream.write(requestStringBytes);  
            outputStream.flush();
            outputStream.close();  
           
           
            // 定义BufferedReader输入流来读取URL的响应
            in = new BufferedReader(
                    new InputStreamReader(conn.getInputStream(),"UTF-8"));
            String line;
            while ((line = in.readLine()) != null) {
                result += line;
            }
        } catch (Exception e) {
            System.out.println("发送 POST 请求出现异常！"+e);
            e.printStackTrace();
        }
        //使用finally块来关闭输出流、输入流
        finally{
            try{
                if(out!=null){
                    out.close();
                }
                if(in!=null){
                    in.close();
                }
            }
            catch(IOException ex){
                ex.printStackTrace();
            }
        }
        return result;
    }