Map转JavaBean

简介

Map转换生成JavaBean是我们在实际项目开发中经常用到的功能，比如：在Servlet中，我们常通过request.getParameterMap()获取前端页面传递过来的数据，然后再将其转换成对应的JavaBean。

待测试的JavaBean类

• Dept类

@Getter
@Setter
@NoArgsConstructor
@AllArgsConstructor
@Builder
@ToString
public class Dept {
	/**
	 * 部门编号
	 */
    private Integer deptno;
    /**
     * 部门名称
     */
    private String dname;
    /**
     * 部门地址
     */
    private String loc;
}

• User

@Getter
@Setter
@NoArgsConstructor
@AllArgsConstructor
@Builder
@ToString
public class User {
    private int id;
    private String username;
    private String email;
    private boolean isAdmin;

    private LocalDate birth;

    private BigDecimal price;
    private String[] array;
    private List<String> list;
    private Map<Integer, String> map;
    private Dept dept;
}

方式一：自定义工具类

• 工具类

public class Map2JavaBeanUtil {

    public static Object mapToObject(Map<String, Object> map, Class<?> clazz) throws Exception {
        if (map == null) {
            return null;
        }
        Object obj = clazz.getDeclaredConstructor().newInstance();
        BeanInfo beanInfo = Introspector.getBeanInfo(obj.getClass());
        PropertyDescriptor[] propertyDescriptors = beanInfo.getPropertyDescriptors();
        for (PropertyDescriptor property : propertyDescriptors) {
            Method setter = property.getWriteMethod();
            if (setter != null) {
                Object o = map.get(property.getName());
                if (o != null) {
                    setter.invoke(obj, o);
                }
            }
        }
        return obj;
    }

}

• 测试代码

public static void main(String[] args) throws Exception {
        Map<String, Object> map = new HashMap<>();
        map.put("id", 1234);
        map.put("username", "zhangsan");
        map.put("email", "[e-mail]");
        map.put("isAdmin", true);
        map.put("birth", LocalDate.now());
        map.put("price", new BigDecimal(22));
        map.put("array", new String[]{"aa", "bb", "cc", "dd"});
        map.put("list", List.of("11", "22", "33", "44"));
        map.put("dept", new Dept(10, "sales", "chicago"));
        map.put("map", Map.of("a", "aa", "b", "bb", "c", "cc"));
        Object o = Map2JavaBeanUtil.mapToObject(map, User.class);
        System.out.println(o);
    }

• 结果

方式二：commons-beanutils

• Maven依赖

<dependency>
    <groupId>commons-beanutils</groupId>
    <artifactId>commons-beanutils</artifactId>
    <version>1.9.4</version>
</dependency>

• 测试代码

public static void main(String[] args) throws Exception {
    Map<String, Object> map = new HashMap<>();
    map.put("id", 1234);
    map.put("username", "zhangsan");
    map.put("email", "[e-mail]");
    map.put("isAdmin", true);
    map.put("birth", LocalDate.now());
    map.put("price", new BigDecimal(22));
    map.put("array", new String[]{"aa", "bb", "cc", "dd"});
    map.put("list", List.of("11", "22", "33", "44"));
    map.put("dept", new Dept(10, "sales", "chicago"));
    map.put("map", Map.of("a", "aa", "b", "bb", "c", "cc"));
    //Object o = Map2JavaBeanUtil.mapToObject(map, User.class);
    //System.out.println(o);

    User user = new User();
    BeanUtils.populate(user, map);
    System.out.println(user);
}

• 结果