//获取json对象
BufferedReader br = new BufferedReader(new
        InputStreamReader(req.getInputStream(), "UTF-8"));
String line = null;
StringBuilder sb = new StringBuilder();
while ((line = br.readLine()) != null) {
    sb.append(line);
}
String reqBody = sb.toString();

//转成map
Map maps = (Map) JSON.parse(reqBody)

json转map:https://www.cnblogs.com/jpfss/p/8625526.html