jackson简单总结代码及jar包

package com.Jtianlin.test; import java.io.IOException; import java.util.List; import java.util.Map; import org.codehaus.jackson.JsonParseException; import org.codehaus.jackson.map.JsonMappingException; import org.codehaus.jackson.map.ObjectMapper; public class JsonToBeans { public static void main(String[] args) throws Exception { //将json字符串转换成java对象 String userJson = "{\"username\":\"jzx\",\"age\":10}"; ObjectMapper objectMapper = new ObjectMapper(); User user = objectMapper.readValue(userJson,User.class); System.out.println(user+":"+user.getUsername()+","+ user.getAge()); //打印结果：com.Jtianlin.test.User@c2a132:jzx,10 //将json字符串数组转换成java对象list集合。直接转换成list集合较为复杂，本例通过一个过渡对象 //该对象里面存有一个list的java对象集合。通过转换成对象来实现集合对象的转换。 String userListJson = "{\"userList\":[{\"username\":\"sss\",\"age\":11},{\"username\":\"hsj\",\"age\":12}]}"; ListBean listBeans = objectMapper.readValue(userListJson, ListBean.class); System.out.println(listBeans.getUserList()); //打印结果：[com.Jtianlin.test.User@1e0bc08, com.Jtianlin.test.User@158b649] //将json字符串转换成map集合，可以通过键来取得值。 String mapJson = "{\"username\":\"hsj\",\"age\":12}"; Map userMap = objectMapper.readValue(mapJson, Map.class); System.out.println(userMap+":" + userMap.get("username")+","+userMap.get("age") ); //打印结果：{username=hsj, age=12}:hsj,12 //将json字符串数组转换成Map的list集合。 String json ="[{\"username\":\"sss\",\"age\":11},{\"username\":\"hsj\",\"age\":12}]}"; List<Map> list = objectMapper.readValue(json, List.class); System.out.println(list.get(0).get("username")); //打印结果：sss } }