Java中实体与Map之间的相互转换代码示例

public static Map<String, Object> objectToMap(Object obj) throws IllegalAccessException {
    Map<String, Object> map = new HashMap<>();
    Class<?> clazz = obj.getClass();
    for (Field field : clazz.getDeclaredFields()) {
        field.setAccessible(true);
        String fieldName = field.getName();
        Object value = field.get(obj);
        map.put(fieldName, value);
    }
    return map;
}

public static Map<String, Object> objectToMap(Object obj) {
    return Arrays.stream(obj.getClass().getDeclaredFields())
            .peek(field -> field.setAccessible(true))
            .collect(Collectors.toMap(Field::getName, field -> {
                try {
                    return field.get(obj);
                } catch (IllegalAccessException e) {
                    return null;
                }
            }));
}

import java.lang.reflect.Field;
import java.util.HashMap;
import java.util.Map;

public class MapToEntity {
    public static void main(String[] args) throws IllegalAccessException {
        Map<String, Object> map = new HashMap<>();
        map.put("name", "张三");
        map.put("age", 25);

        User user = mapToEntity(map, User.class);
        System.out.println(user);
    }

    public static <T> T mapToEntity(Map<String, Object> map, Class<T> clazz) {
        T obj = null;
        try {
            obj = clazz.newInstance();
            for (Map.Entry<String, Object> entry : map.entrySet()) {
                String key = entry.getKey();
                Object value = entry.getValue();
                Field field = clazz.getDeclaredField(key);
                field.setAccessible(true);
                field.set(obj, value);
            }
        } catch (InstantiationException | IllegalAccessException | NoSuchFieldException e) {
            e.printStackTrace();
        }
        return obj;
    }
}

class User {
    private String name;
    private int age;

    // 省略getter和setter方法
}

<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-databind</artifactId>
    <version>2.12.5</version>
</dependency>

public class User {
    private String name;
    private int age;

    // 省略getter和setter方法
}

import com.fasterxml.jackson.databind.ObjectMapper;
import java.util.HashMap;
import java.util.Map;

public class MapToEntity {
    public static void main(String[] args) throws Exception {
        Map<String, Object> map = new HashMap<>();
        map.put("name", "张三");
        map.put("age", 25);

        ObjectMapper objectMapper = new ObjectMapper();
        User user = objectMapper.convertValue(map, User.class);
        System.out.println(user);
    }
}