fastjson解析

来源：互联网发布：java管理系统界面编辑：程序博客网时间：2024/05/18 02:09

听闻阿里的fastJson特别的厉害.就下载了,稍微的试了一下:

本次使用:fastjson-1.2.8.jar

本次只是比较简单的对象和json之间的转换,没有涉及到复杂对象与json之间的转换.

有两个实体类,User和GroupBean,本次暂时只是涉及到User类

public class User {
   private String id;
   private String name;
   private Integer age;

补充set和get方法}

public class GroupBean {
   private String id;
   private List<User> list=new ArrayList<User>();
   private Set<User> set=new HashSet<User>();
   private Map<String,User> map=new HashMap<String,User>();

补充set和get方法}

import org.junit.Test;
import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONArray;
import com.alibaba.fastjson.JSONObject;
import com.alibaba.fastjson.TypeReference;
import com.alibaba.fastjson.parser.Feature;

public class MyTest {

   //简单对象的转换
   @Test
   public void test1() {
       User user1 = new User("1","caocao",20);
       User user2 = new User("2","liubei",22);
       List<User> list=new ArrayList<User>();
       Set<User> set=new HashSet<User>();
       Map<String,User> map=new HashMap<String,User>();
       list.add(user1);
       list.add(user2);
       set.add(user1);
       set.add(user2);
       map.put("user1", user1);
       map.put("user2", user2);

       //把对象转换成json
       String jsonString1 = JSON.toJSONString(user1);
       String jsonString2= JSON.toJSONString(user2);
       System.out.println(jsonString1); //打印转换成json的字符串
       //{"age":20,"id":"1","name":"caocao"}
       System.out.println(user1); //直接打印对象
       //User [id=1, name=caocao, age=20]

       System.out.println(jsonString2);
       //{"age":22,"id":"2","name":"liubei"}
       System.out.println(user2);
       //User [id=2, name=liubei, age=22]

       String jsonString3 = JSON.toJSONString(list);
       System.out.println(jsonString3);
       //[{"age":20,"id":"1","name":"caocao"},{"age":22,"id":"2","name":"liubei"}]
       String jsonString4 = JSON.toJSONString(set);
       System.out.println(jsonString4);
       //[{"age":20,"id":"1","name":"caocao"},{"age":22,"id":"2","name":"liubei"}]
       String jsonString5 = JSON.toJSONString(map);
       System.out.println(jsonString5);
       //{"user2":{"age":22,"id":"2","name":"liubei"},"user1":{"age":20,"id":"1","name":"caocao"}}


       //把json转换成bean
       Object parse1 = JSON.parse(jsonString1); //直接进行解析
       System.out.println(parse1);
       //{"id":"1","name":"caocao","age":20}

       //强转类型,不能进行强制类型的转换,会报出类转换异常的
       //User parse2=(User)parse1;

       User parseObject = JSON.parseObject(jsonString2, User.class); //添加类进行解析,直接得到bean
       System.out.println(parseObject+"~~"+parseObject.getName());
       //User [id=2, name=liubei, age=22]~~liubei


       //直接解析出报错
   //   JSONObject parseObject2 = JSON.parseObject(jsonString3);

       //添加类型解析
       List<User> parseObject2 = JSON.parseObject(jsonString3, new TypeReference<List<User>>() {});
       System.out.println(parseObject2);
       //[User [id=1, name=caocao, age=20], User [id=2, name=liubei, age=22]]

       //按照数据的类型解析
       JSONArray parseArray = JSON.parseArray(jsonString3);
       System.out.println(parseArray);
       //[{"id":"1","name":"caocao","age":20},{"id":"2","name":"liubei","age":22}]


       //解析出具体的map类型
       Map<String, User> parseObject5 = JSON.parseObject(jsonString5, new TypeReference<Map<String,User>>(){});
       System.out.println(parseObject5);
       //{user2=User [id=2, name=liubei, age=22], user1=User [id=1, name=caocao, age=20]}
       //粗略的解析出了map
       Map parseObject6 = JSON.parseObject(jsonString5, Map.class);
       System.out.println(parseObject6);
       //{user2={"id":"2","name":"liubei","age":22}, user1={"id":"1","name":"caocao","age":20}}

   }
}

本次博客就先到这里,再过段时间我会把复杂和json之间的解析发出来.

如果错误,敬请指正

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