在MapStruct中使用多个源对象

喜欢ヅ旅行 2023-01-15 02:11 201阅读 0赞

在MapStruct中使用多个源对象

# 1.介绍 #

如何在MapStruct中使用多个源对象。

# 2.单个源对象 #

MapStruct最常见的用例是将一个对象映射到另一个对象。 假设我们有一个Customer类：

@Data
    @AllArgsConstructor
    @NoArgsConstructor
    public class Customer { 
        private String firstName;
        private String lastName;
    }

@Data
    @AllArgsConstructor
    @NoArgsConstructor
    public class CustomerDto { 
        private String forename;
        private String surname;
    }

定义一个映射器，将一个Customer对象映射到一个CustomerDto对象：

# 3.多个源对象 #

有时我们希望目标对象具有来自多个源对象的属性。

假设 编写了一个购物应用程序。需要构造一个送货地址：

@Data
    @AllArgsConstructor
    @NoArgsConstructor
    public class DeliveryAddress { 
        private String forename;
        private String surname;
        private String street;
        private String postalcode;
        private String county;
    }

每个客户可以有多个地址。 一个可以是家庭住址。 另一个可以是工作地址：

@Data
    @AllArgsConstructor
    @NoArgsConstructor
    public class Address { 
        private String street;
        private String postalcode;
        private String county;
    }

需要一个映射器，该映射器可以根据客户及其地址之一创建收获地址。 MapStruct通过具有多个源对象来支持此操作：

@Mapper(componentModel = "spring")
    public interface DeliveryAddressMapper { 
        @Mapping(source = "customer.firstName", target = "forename")
        @Mapping(source = "customer.lastName", target = "surname")
        @Mapping(source = "address.street", target = "street")
        @Mapping(source = "address.postalcode", target = "postalcode")
        @Mapping(source = "address.county", target = "county")
        DeliveryAddress from(Customer customer, Address address);
    }

单元测试

@Test
        public void test12() { 
    
            Customer customer = new Customer();
            customer.setFirstName("张");
            customer.setLastName("三");
    
    
            Address homeAddress = new Address();
            homeAddress.setStreet("科技二路");
            homeAddress.setCounty("雁塔区");
            homeAddress.setPostalcode("89123");
    
            DeliveryAddress deliveryAddress = deliveryAddressMapper.from(customer, homeAddress);
    
            assertEquals(deliveryAddress.getForename(), customer.getFirstName());
            assertEquals(deliveryAddress.getSurname(), customer.getLastName());
            assertEquals(deliveryAddress.getStreet(), homeAddress.getStreet());
            assertEquals(deliveryAddress.getCounty(), homeAddress.getCounty());
            assertEquals(deliveryAddress.getPostalcode(), homeAddress.getPostalcode());
        }

# 4.使用@MappingTarget更新已存在的对象 #

到现在为止，已经有了可以创建目标类新实例的映射器。 使用多个源对象，还可以提供一个要更新的实例。

使用@MappingTarget对其进行处理：

@Test
        public void test13() { 
    
            DeliveryAddress deliveryAddress = new DeliveryAddress();
            deliveryAddress.setForename("张");
            deliveryAddress.setSurname("三");
            deliveryAddress.setStreet("科技二路");
            deliveryAddress.setCounty("雁塔区");
            deliveryAddress.setPostalcode("89123");
            ;
    
    
            Address newAddress = new Address();
            newAddress.setStreet("西长安街");
            newAddress.setCounty("长安区");
            newAddress.setPostalcode("12345");
    
    
            DeliveryAddress updatedDeliveryAddress = deliveryAddressMapper.updateAddress(deliveryAddress, newAddress);
    
    
            assertSame(deliveryAddress, updatedDeliveryAddress);
    
            assertEquals(deliveryAddress.getStreet(), newAddress.getStreet());
            assertEquals(deliveryAddress.getCounty(), newAddress.getCounty());
            assertEquals(deliveryAddress.getPostalcode(), newAddress.getPostalcode());
        }

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