一个测试类了解BeanUtils.copyProperties

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.Getter;
import lombok.NoArgsConstructor;
import lombok.Setter;
import lombok.ToString;
import org.springframework.beans.BeanUtils;

import java.math.BigDecimal;

public class Test2 {
    
    public static void main(String[] args) {
    
        UserDto userDto = new UserDto();
        //BeanUtils.copyProperties(a,b)是将a的数据拷贝给b
        User user = new User();
        Salary salary = new Salary();
        //a中与b中相同的属性才会被替换（不同需要手动set），复制类即b不管是否有值；
        BeanUtils.copyProperties(userDto, user);

        //b中的存在的属性，a中没有默认null
        System.out.println(user + "--" + user.getDefaultClass().getInnerNum());
        //User(id=2, name=2, sex=2, [email protected], innerClass=User.InnerClass(innerNum=4))--2

        BeanUtils.copyProperties(userDto, salary);
        System.out.println(salary);
        //Salary(id=2, salary=null, idCard=null)
    }
}

@Getter
@Setter
@AllArgsConstructor
@NoArgsConstructor
class DefaultClass {
    
    Integer innerNum = 4;
}

@ToString
@Setter//Spring的BeanUtils的CopyProperties方法复制类需要有setter方法；
@Getter
class User {
    
    private Integer id = 4;
    private String name = "4";
    private String sex = "4";
    private DefaultClass defaultClass = new DefaultClass(4);
    private InnerClass innerClass = new InnerClass();
// private User.InnerClass innerClass2 = new User.InnerClass();属性完全相同的内部类，但是不是同一个内部类即不是同一个对象，不会复制

    @Data
    class InnerClass {
    
        Integer innerNum = 4;
    }
}

@Data
class Salary {
    
    private Integer id;
    private BigDecimal salary;
    private String idCard;

}

@Getter
//Spring的BeanUtils的CopyProperties方法被复制类需要有getter方法；
class UserDto {
    
    private Integer id = 2;
    private String name = "2";
    private String sex = "2";
    private DefaultClass defaultClass = new DefaultClass(2);
    private InnerClass innerClass = new InnerClass();
// private UserSalaryDto.InnerClass innerClass2 = new UserSalaryDto.InnerClass();

    class InnerClass {
    
        Integer innerNum = 2;
    }
}