map转换成JSON的3种方式

1. alibaba

<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>fastjson</artifactId>
    <version>1.2.41</version>
</dependency>

JSONUtils.toJSONString(requestMap); 

2. json-lib

<dependency>
            <groupId>net.sf.json-lib</groupId>
            <artifactId>json-lib</artifactId>
            <version>2.5</version>
</dependency>

JSONObject jsonObject = JSONObject.fromObject(map);

String result = jsonObject.toString();

3. google

<dependency>
    <groupId>com.google.code.gson</groupId>
    <artifactId>gson</artifactId>
    <version>2.3.1</version>

</dependency>

new Gson().toJson(param);