map转换成JSON的3种方法

http://www.json.cn/JSON格式校验

1 json-lib

<dependency>
            <groupId>net.sf.json-lib</groupId>
            <artifactId>json-lib</artifactId>
            <version>2.4</version>
             <classifier>jdk15</classifier>
        </dependency>

import java.util.HashMap;
import java.util.Map;  

import net.sf.json.JSONObject;  

public class aaa {
      public static void main(String[] args) {
            Map map = new HashMap();
            map.put("msg", "yes");//map里面装有yes
            JSONObject jsonObject = JSONObject.fromObject(map);
            System.out.println("输出的结果是：" + jsonObject);
            //3、将json对象转化为json字符串
            String result = jsonObject.toString();
            System.out.println(result);
        }
}  

json-lib是一个比较老的解决方案，近几年都没有升级过，它的适用环境是JDK1.5，使用JDK1.6就有可能会报错。所以配置上加入classifier-jdk15来解决这个问题。JAR下载链接

2alibaba

JSONUtils.toJSONString(requestMap);    com.alibaba.fastjson.JSON

maven坐标

<!-- https://mvnrepository.com/artifact/com.alibaba/fastjson -->
<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>fastjson</artifactId>
    <version>1.2.41</version>
</dependency>  

3  google

new Gson().toJson(param);         com.google.gson.2.2.2.jar       JAR包下载

maven坐标

<!-- https://mvnrepository.com/artifact/com.google.code.gson/gson -->
<dependency>
    <groupId>com.google.code.gson</groupId>
    <artifactId>gson</artifactId>
    <version>2.3.1</version>
</dependency>  

--------------------===-------------------------附--MAP的ASCII排序-----------------------===------------------------

StringBuilder sb = new StringBuilder();
    List<String> keys = new ArrayList<String>(map.keySet());
    Collections.sort(keys);//排序。
    for(String k : keys){
        String v = params.get(k);
        if(StringUtils.isNotEmpty(v)){
            sb.append(v);
        }
    }
    //return MD5.toMD5(sb+key, "UTF-8");这个就不用看了~~~