GitHub
https://github.com/alibaba/fastjson
fastjson是目前java语言中最快的json库，比 jackson 和 gson 都要快。
Maven
<!-- https://mvnrepository.com/artifact/com.alibaba/fastjson --><dependency> ???<groupId>com.alibaba</groupId> ???<artifactId>fastjson</artifactId> ???<version>1.2.49</version></dependency>Methods
Object → String
将 VO 转为 String
将 Map 转为 String
将 Collection 转为 String
将 Array 转为 String
String jsonString = JSON.toJSONString(object)String → T 或 Map<String, Object>
将 String 转为 T
VO vo = JSON.parseObject(text, VO.class)将 String 转为 JSONObject（即 Map<String, Object>）
JSONObject object = JSON.parseObject(text)String → List< T > 或 List< Object >
将 String 转为 List
List<VO> list= JSONObject.parseArray(text, VO.class);将 String 转为 JSONArray（即 List< Object >）
JSONArray array = JSON.parseArray(text)Samples
import java.util.ArrayList;import java.util.HashMap;import java.util.List;import java.util.Map;import com.alibaba.fastjson.JSON;import com.alibaba.fastjson.JSONArray;import com.alibaba.fastjson.JSONObject;import hust.zeng.utils.pojo.Group;import hust.zeng.utils.pojo.User;public class JsonUtil { ???public static void main(String[] args) { ???????System.out.println("1.Object >> String"); ???????// 1.1.将普通对象转为JsonString ???????Group group = new Group(); ???????group.setId(1L); ???????group.setName("group1"); ???????User guestUser = new User(); ???????guestUser.setId(10L); ???????guestUser.setName("admin"); ???????User rootUser = new User(); ???????rootUser.setId(11L); ???????rootUser.setName("guest"); ???????group.addUser(guestUser); ???????group.addUser(rootUser); ???????String voString = JSON.toJSONString(group); ???????System.out.println(voString); ???????// 1.2.将Map对象转为JsonString ???????HashMap<String, Object> map = new HashMap<>(); //JSONObject map = new JSONObject(); ???????map.put("id", 7); ???????HashMap<String, Object> info = new HashMap<>(); ???????info.put("name", "HUST"); ???????info.put("adreess", "wuhan"); ???????map.put("info", info); ???????String mapStr = JSON.toJSONString(map); ???????System.out.println(mapStr); ???????// 1.3.将List对象转为JsonString ???????ArrayList<String> list = new ArrayList<>(); //JSONArray list = new JSONArray(); ???????list.add("aa"); ???????list.add("bb"); ???????String listStr = JSON.toJSONString(list); ???????System.out.println(listStr); ???????// 1.4.将数组对象转为JsonString ???????Object[] array = new Object[3]; ???????array[0] = 1; ???????array[1] = 2; ???????array[2] = 3; ???????String arrayStr = JSON.toJSONString(array); ???????System.out.println(arrayStr); ???????System.out.println("2.String → T 或 Map<String, Object>"); ???????// 2.1.将String转为T ???????Group group2 = JSON.parseObject(voString, Group.class); ???????System.out.println(group2); ???????// 2.2.将String转为JSONObject ???????Map<String, Object> map2 = JSON.parseObject(mapStr); ???????System.out.println(map2); ???????System.out.println("3.String → List<T> 或 List<Object>"); ???????????????// 3.1.将String转为List<T> ???????List<String> list2 = JSON.parseArray(listStr, String.class); ???????System.out.println(list2); ???????// 3.2.将String转为JSONArray ???????List<Object> array2 = JSON.parseArray(arrayStr); ???????System.out.println(array2); ???}}fastjson
原文地址：https://www.cnblogs.com/zengzhihua/p/9707048.html