使用Jackson实现Map与Bean互转方式
Jackson Map与Bean互转
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
下面就列举了几种使用方法
1、pom.xml
com.fasterxml.jackson.core jackson-databind2.9.6 compile
2、java 代码
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BeanMap 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MapPerson 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Beanpublic static Object mapToBean(Map map, Class clazz) throws Exception {return mapper.readValue(objectToString(map), clazz); }// 将Bean转成Mappublic static Map beanToMap(Object obj) throws Exception {return mapper.readValue(objectToString(obj), Map.class); }}
3、Person 类
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; }@Overridepublic String toString() {return "Person{" +"age=" + age +", name='" + name + '\'' +", birthday=" + birthday +'}'; }}
Jackson-ObjectMapper json字符串、bean、map、list互相转换 1、对象转json字符串
ObjectMapper mapper = new ObjectMapper(); User user = new User(); String userJson = mapper.writeValueAsString(user);
2、Map转json字符串
ObjectMapper mapper = new ObjectMapper(); Map map = new HashMap(); String json = mapper.writeValueAsString(map);
3、数组list转json字符串
ObjectMapper mapper = new ObjectMapper(); User[] uArr = {user1, user2}; String jsonfromArr = mapper.writeValueAsString(uArr);
4、json字符串转对象
ObjectMapper mapper = new ObjectMapper(); String expected = "{\"name\":\"ZhangSan\"}"; User user = mapper.readValue(expected, User.class);
5、json字符串转Map
ObjectMapper mapper = new ObjectMapper(); String expected = "{\"name\":\"ZhangSan\"}"; Map userMap = mapper.readValue(expected, Map.class);
6、json字符串转对象数组List
ObjectMapper mapper = new ObjectMapper(); String expected = "[{\"name\":\"Zhangsan\"},{\"name\":\"Lisi\"}]"; CollectionType listType = mapper.getTypeFactory().constructCollectionType(ArrayList.class, User.class); ListuserList = mapper.readValue(expected, listType);
7、json字符串转Map数组List