<!-- https://mvnrepository.com/artifact/com.alibaba/fastjson -->
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>fastjson</artifactId>
<version>1.2.41</version>
</dependency>
com.alibaba.fastjson.JSON
not
com.alibaba.dubbo.common.json.JSONObject;
String to JSON:
JSONObject jsonResult = JSONObject.parseObject(contract.getParam());