FastJson、Jackson处理Json转换对象、复杂对象问题FastJson、Jackson处理Json转换对象、复杂对象问题
在开发过程中最常见的就是Json格式转化问题。包括Json转对象，转数据，转Map等等。常见处理json的类库FastJson，Jackson为此我针对他们做了⼀些总结，如有⽋缺可以留⾔。希望可以帮助⼤家。
FastJson
准备两个套娃的类
@Data
@AllArgsConstructor
@NoArgsConstructor
public class FastJsonPerson {
private String name;
private Integer agexx;
private String other;
private List<Card> cards;
}
@Data
@NoArgsConstructor
@AllArgsConstructor
public class Card {
private String cardName;
private Date cardTime;
}
1.对象转字符串
@Test
public void transformString(){
FastJsonPerson person;
person =new FastJsonPerson();
person.setName("兵长");
person.setAgexx(18);
person.setOther("其他要被屏蔽");
person.setCards(Arrays.asList(new Card("招商",new Date()),
new Card("浦发",new Date())));
String personString = JSONString(person);
System.out.println(personString);
}
// 结果：{"agexx":18,"cards":[{"cardName":"招商","cardTime":1631188795258},{"cardName":"浦发","cardTime":1631188795258}],"name":"兵长","other":"其他要被屏蔽"}
在转化的过程不想要某个字段可以加上@JSONField(serialize = false)，注意不是@jsonIgnore，那个是jackson的。
在转化的过程中还想更换字段别名@JSONField(name=“xxx”)
格式化⽇期@JSONField(format=“yyyy-MM-dd HH:mm:ss”)
接下来改变对应的实体类完成上述三个要求。
private String name;
@JSONField(name="age")
private Integer agexx;
@JSONField(serialize =false)
private String other;
private List<Card> cards;
}
@Data
@NoArgsConstructor
@AllArgsConstructor
public class Card {
private String cardName;
@JSONField(format="yyyy-MM-dd HH:mm:ss")
private Date cardTime;
}
再次执⾏上边的测试⽅法，你会发现结果变成;agexx—>age ，时间格式变成了正常的，other字段被忽略。
{"age":18,"cards":[{"cardName":"招商","cardTime":"2021-09-09 20:12:26"},{"cardName":"浦发","cardTime":"2021-09-09 20:12:26"}],"name":"兵长"}
2.字符串转对象，集合对象；
@Test
public void stringToObject() {
//针对于简单的字符串，我们可以通过转成Array，然后通过名字获取内容。
String s = "{\"age\":18,\"cards\":[{\"cardName\":\"招商\",\"cardTime\":\"2021-09-09 20:12:26\"},{\"cardName\":\"浦发\",\"cardTime\":\"2021-09-09 20:12:2 6\"}],\"name\":\"兵长\"}";
JSONObject object = JSON.parseObject(s);
System.out.("age"));
System.out.("name"));
System.out.("cards"));
String list = "[{\"age\":18,\"cards\":[{\"cardName\":\"招商\",\"cardTime\":\"2021-09-09 20:12:26\"},{\"cardName\":\"浦发\",\"cardTime\":\"2021-09-09 20:1 2:26\"}],\"name\":\"兵长\"},{\"age\":18,\"cards\":[{\"cardName\":\"招商\",\"cardTime\":\"2021-09-09 20:12:26\"},{\"cardName\":\"浦发\",\"cardTime\":\"2021-09-09 20:12:26\"}],\"name\":\"兵长\"}]";
List<FastJsonPerson> personList = JSON.parseArray(list, FastJsonPerson.class);
System.out.println(personList);
}
3.字符串转Map
@Test
public void stringToMap(){
String s ="{\"age\":18,\"cards\":[{\"cardName\":\"招商\",\"cardTime\":\"2021-09-09 20:12:26\"},{\"cardName\":\"浦发\",\"cardTime\":\"2021-09-09 20:12:2 6\"}],\"name\":\"兵长\"}";
Map map =(Map<String,Object>)JSON.parseObject(s);
System.out.println(map);
}
fastjson忽略属性Jackson
准备两个套娃类
private String cardName;
private Date cardTime;
}
@Data
@NoArgsConstructor
@AllArgsConstructor
public class JacksonPerson {
private String name;
private Integer agexx;
private String other;
private List<JacksonCard> cards;
}
1.对象转字符串
@SneakyThrows
@Test
public void transformToString (){
JacksonPerson person =new JacksonPerson();
person.setName("兵长");
person.setAgexx(18);
person.setOther("其他要被屏蔽");
person.setCards(Arrays.asList(new JacksonCard("招商",new Date()),
new JacksonCard("浦发",new Date())));
ObjectMapper objectMapper =new ObjectMapper();
System.out.println(objectMapper.writeValueAsString(person));
}
// 结果：{"name":"兵长","agexx":18,"other":"其他要被屏蔽","cards":[{"cardName":"招商","cardTime":1631242139184},{"cardName":"浦发","cardTime":16312 42139184}]}
在转化的过程不想要某个字段可以加上@JsonIgnore
在转化的过程中还想更换字段别名@JsonProperty(“age”)
格式化⽇期@JsonFormat(pattern = “yyyy-MM-dd HH:mm:ss”, timezone = “GMT+8”)
根据上述描述改造对应的实体类
@Data
@NoArgsConstructor
@AllArgsConstructor
public class JacksonPerson {
private String name;
@JsonProperty("age")
private Integer agexx;
@JsonIgnore
private String other;
private List<JacksonCard> cards;
}
@Data
@NoArgsConstructor
@AllArgsConstructor
public class JacksonCard {
private String cardName;
@JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss", timezone = "GMT+8")
private Date cardTime;
}
2.字符串转对象，对象集合，复杂对象
@Test
public void transformToObject()throws IOException {
String s ="{\"age\":18,\"cards\":[{\"cardName\":\"招商\",\"cardTime\":\"2021-09-09 20:12:26\"},{\"cardName\":\"浦发\",\"cardTime\":\"2021-09-09 20:12:26\" }],\"name\":\"兵长\"}";
String list ="[{\"age\":18,\"cards\":[{\"cardName\":\"招商\",\"cardTime\":\"2021-09-09 20:12:26\"},{\"cardName\":\"浦发\",\"cardTime\":\"2021-09-09 20:12:2 6\"}],\"name\":\"兵长\"},{\"age\":18,\"cards\":[{\"cardName\":\"招商\",\"cardTime\":\"2021-09-09 20:12:26\"},{\"cardName\":\"浦发\",\"cardTime\":\"2021-09-09 20:12:26\"}],\"name\":\"兵长\"}]";
ObjectMapper objectMapper =new ObjectMapper();
System.out.adValue(s, JacksonPerson.class));
List<JacksonPerson> personList =(List<JacksonPerson>)adValue(list, TypeFactory().constructParametricType(List.cl ass, JacksonPerson.class));
System.out.println(personList);
// 如果多层套娃，你可以使TypeReference，万能想要的都有
List<Map<String,Object>> personList1 = adValue(list,new TypeReference<List<Map<String,Object>>>(){});
System.out.println(personList1);
}
下边是JsonUtils⼯具类。
package com.zj.json;
import com.fasterxml.jackson.annotation.JsonInclude;
import com.ype.TypeReference;
import com.fasterxml.jackson.databind.DeserializationFeature;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;
slf4j.Slf4j;
import org.springframework.util.StringUtils;
SimpleDateFormat;
/**
* @description:
* @author: wangdakai
* @date: 2021/9/10
*/
@Slf4j
public class JsonUtils {
private static ObjectMapper objectMapper = new ObjectMapper();
static {
//序列化的时候序列对象的所有属性
objectMapper.setSerializationInclusion(JsonInclude.Include.ALWAYS);
//反序列化的时候如果多了其他属性，不抛出异常
//如果是空对象的时候，不抛异常
//取消时间的转化格式，默认是时间戳，可以取消，同时需要设置要表现的时间格式
objectMapper.setDateFormat(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"));
}
/**
* 对象转Json
* @param obj
* @param <T>
* @return
*/
public static <T>String objectToJson(T obj){
if(obj == null){
return null;
}
}
try {
return obj instanceof String ? (String) obj : objectMapper.writeValueAsString(obj);
} catch (Exception e) {
log.warn("Parse Object to Json error",e);
e.printStackTrace();
return null;
}
}
/**
* json转对象
* @param src
* @param clazz
* @param <T>
* @return
*/
public static <T>T jsonToObject(String src,Class<T> clazz){
if(StringUtils.isEmpty(src) || clazz == null){
return null;
}
try {
return clazz.equals(String.class) ? (T) src : adValue(src,clazz);
} catch (Exception e) {
log.warn("Parse Json to Object error",e);
e.printStackTrace();
return null;
}
}
/**
* json转想要的对象；应对各种复杂格式的对象很万能。
* @param src
* @param typeReference
* @param <T>
* @return
*/
public static <T>T jsonToObject(String src, TypeReference<T> typeReference){
if(StringUtils.isEmpty(src) || typeReference == null){
return null;
}
try {
return (T)(Type().equals(String.class) ? src : adValue(src, typeReference));
} catch (Exception e) {
log.warn("Parse Json to Object error",e);
e.printStackTrace();
return null;
}
}
/**
* json转成对象
* @param str
* @param collectionClass
* @param elementClasses
* @param <T>
* @return
*/
public static <T> T jsonToTransfer(String str, Class<?> collectionClass, Class<?>... elementClasses) {
try {
return (adValue(str, TypeFactory().constructParametricType(collectionClass, elementClasses)); } catch (Exception e) {
log.warn("Parse Json to Object error",e);
e.printStackTrace();
}
return null;
版权声明：本站内容均来自互联网，仅供演示用，请勿用于商业和其他非法用途。如果侵犯了您的权益请与我们联系QQ:729038198，我们将在24小时内删除。
发表评论