本篇内容介绍了“怎么用Jackson实现Map与Bean互转方式”的有关知识，在实际案例的操作过程中，不少人都会遇到这样的困境，接下来就让小编带领大家学习一下如何处理这些情况吧！希望大家仔细阅读，能够学有所成！
在使用 java 开发中，通常需要把 Map 转成 Bean，或把 Bean 转成 Map，这就用的工具类，在此推荐使用import com.fasterxml.jackson.databind.ObjectMapper;包下的ObjectMapper类，比 JsonObject 效率高
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<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.9.6</version>
<scope>compile</scope>
</dependency>package com.jin.demo.jackson;
import com.fasterxml.jackson.databind.ObjectMapper;
import java.util.HashMap;
import java.util.Map;
/**
* 使用 Jackson工具
* map to bean
* bean to map
*
* @auther jinsx
* @date 2019-03-26 16:37
*/
public class JacksonTest {
private static final ObjectMapper mapper = new ObjectMapper();
public static void main(String[] args) throws Exception {
// 测试 将Map转成指定的Bean
Map<String, Object> map = new HashMap<>();
map.put("name", "张三");
Person o = (Person)JacksonTest.mapToBean(map, Person.class);
System.out.println(o);
// 测试 将Bean转成Map
Person person = new Person();
person.setAge(18);
Map map1 = JacksonTest.beanToMap(person);
System.out.println(map1);
}
// 将对象转成字符串
public static String objectToString(Object obj) throws Exception {
return mapper.writeValueAsString(obj);
}
// 将Map转成指定的Bean
public static Object mapToBean(Map map, Class clazz) throws Exception {
return mapper.readValue(objectToString(map), clazz);
}
// 将Bean转成Map
public static Map beanToMap(Object obj) throws Exception {
return mapper.readValue(objectToString(obj), Map.class);
}
}package com.jin.demo.jackson;
import java.io.Serializable;
import java.util.Date;
/**
* @auther jinsx
* @date 2019-03-26 17:30
*/
public class Person implements Serializable {
private int age;
private String name;
private Date birthday;
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Date getBirthday() {
return birthday;
}
public void setBirthday(Date birthday) {
this.birthday = birthday;
}
@Override
public String toString() {
return "Person{" +
"age=" + age +
", name='" + name + '\'' +
", birthday=" + birthday +
'}';
}
}ObjectMapper mapper = new ObjectMapper();
User user = new User();
String userJson = mapper.writeValueAsString(user);ObjectMapper mapper = new ObjectMapper();
Map map = new HashMap();
String json = mapper.writeValueAsString(map);ObjectMapper mapper = new ObjectMapper();
User[] uArr = {user1, user2};
String jsonfromArr = mapper.writeValueAsString(uArr);ObjectMapper mapper = new ObjectMapper();
String expected = "{\"name\":\"ZhangSan\"}";
User user = mapper.readValue(expected, User.class);ObjectMapper mapper = new ObjectMapper();
String expected = "{\"name\":\"ZhangSan\"}";
Map userMap = mapper.readValue(expected, Map.class);ObjectMapper mapper = new ObjectMapper();
String expected = "[{\"name\":\"Zhangsan\"},{\"name\":\"Lisi\"}]";
CollectionType listType = mapper.getTypeFactory().constructCollectionType(ArrayList.class, User.class);
List<User> userList = mapper.readValue(expected, listType);ObjectMapper mapper = new ObjectMapper();
String expected = "[{\"name\":\"Zhangsan\"},{\"nameEn\":\"Lisi\"}]";
CollectionType listType = mapper.getTypeFactory().constructCollectionType(ArrayList.class, Map.class);
List<Map<String,Object>> userList = mapper.readValue(expected, listType);ObjectMapper mapper = new ObjectMapper();
String expected = "[{\"name\":\"Zhangsan\"},{\"nameEn\":\"Lisi\"},{\"name\":\"Test\"}]";
ArrayList arrayList = mapper.readValue(expected, ArrayList.class);ObjectMapper mapper = new ObjectMapper();
//设置date转换格式
SimpleDateFormat fmt = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
mapper.setDateFormat(fmt);
String expected = "{\"name\":\"ZhangSan\",\"bir\":\"2021-04-15 14:00:00\"}";
User user = mapper.readValue(expected, User.class);ObjectMapper mapper = new ObjectMapper();
//设置忽略未知字段
mapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
String expected = "{\"name\":\"ZhangSan\",\"job\":\"teacher\"}";
User user = mapper.readValue(expected, User.class);“怎么用Jackson实现Map与Bean互转方式”的内容就介绍到这里了，感谢大家的阅读。如果想了解更多行业相关的知识可以关注亿速云网站，小编将为大家输出更多高质量的实用文章！
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