由于在实际工作中使用fastjson解析嵌套map的场景非常多，所以在此备忘一下：

引入阿里的fastjson的pom：

     <dependency><groupId>com.alibaba</groupId><artifactId>fastjson</artifactId><version>1.2.15</version>
</dependency>

一个比较复杂的json例子：

{"actId": "1800025", "originCode": 1, "role": "TEACHER", "time": 1471077017804, "userId": "1111", "userName": "测试教师", "userIcon": "xyz", "userIp": "1.1.1.1", "countyId": "370105", "countyName": "天桥区", "schoolId": "1234", "schoolName": "测试小学", "data": {"subjectId": "020", "subjectName": "数学", "uploadFileList": [{"teachFileType": "1", "custom": "xtz"}, {"teachFileType": "1"}]}
}

使用fastjson的解析代码：

import com.alibaba.fastjson.JSON;import java.util.List;
import java.util.Map;/*** Created by Administrator on 2016/8/12.*/
public class ParserJson {/***** @param map 需要打印的Map结构*/public static void showMap(Map<String,Object> map){for(Map.Entry<String,Object> kv:map.entrySet()){System.out.println(kv.getKey()+"  "+kv.getValue());}}public static void main(String[] args) throws Exception {String json="{\"actId\":\"2300003\",\"originCode\":1,\"role\":\"TEACHER\"" +",\"time\":1470126407000,\"userId\":\"1111\",\"userName\":\"测试教师\",\"userIcon\":\"xyz\",\"userIp\":\"1.1.1.1\",\"countyId\":\"370105\",\"countyName\":\"天桥区\",\"schoolId\":\"1234\",\"schoolName\":\"测试小学\",\"data\":{\"subjectId\":\"020\",\"subjectName\":\"数学\"," +"\"uploadFileList\":[{\"teachFileType\":\"1\"},{\"teachFileType\":\"1\",\"custom\":\"xt\"},{\"teachFileType\":\"1\"}]}}";Map<String,Object> map=(Map)JSON.parse(json);System.out.println("打印第一层map");showMap(map);Map<String,Object> dataMap=(Map<String, Object>) map.get("data");System.out.println("打印第二层map");showMap(dataMap);System.out.println("打印第三层list+map");List<Map<String,Object>> fileList= (List<Map<String, Object>>) dataMap.get("uploadFileList");for(Map<String,Object> soj:fileList){System.out.println(soj);Map<String,Object> detailData=soj;showMap(detailData);System.out.println("----------------------------------------");}}}

解析结果：

ParserJson
打印第一层map
role  TEACHER
data  {"uploadFileList":[{"teachFileType":"1"},{"custom":"xt","teachFileType":"1"},{"teachFileType":"1"}],"subjectId":"020","subjectName":"数学"}
actId  2300003
userName  测试教师
userId  1111
countyId  370105
schoolId  1234
userIp  1.1.1.1
originCode  1
time  1470126407000
userIcon  xyz
schoolName  测试小学
countyName  天桥区
打印第二层map
uploadFileList  [{"teachFileType":"1"},{"custom":"xt","teachFileType":"1"},{"teachFileType":"1"}]
subjectId  020
subjectName  数学
打印第三层list+map
{"teachFileType":"1"}
teachFileType  1
----------------------------------------
{"custom":"xt","teachFileType":"1"}
custom  xt
teachFileType  1
----------------------------------------
{"teachFileType":"1"}
teachFileType  1
----------------------------------------Process finished with exit code 0