Principles and configurations of attribute name mapping in the MapStruct Core framework

MapStruct is a Java annotation processor framework that automatically generates type safe, high -performance mapping code.It can help developers perform attribute names between different Java classes to reduce the workload of manually writing duplicate code.In the core framework of Mapstruct, the principle and configuration of attribute name mapping is very important. 1. Principles of attribute name mapping: In MapStructs, the attribute name mapping is achieved by generating the mapping code of the Java class.Developers need to use the @Mapper annotation marker mapping interface and define the mapping rules in the interface method.MapStruct generates a mapping class that implements the interface based on these rules.In this mapping class, MapStruct will be maximized from the attribute name of the source and target class. MapStruct supports the following attribute name mapping methods: -Mapstruct mapping: MapStruct will automatically mappore if the source and target classes exist with the same name. -F different attribute name mapping: If the attribute names of the source and the target class are different, you can specify the mapping relationship between the attributes by defining a @Mapping annotation. -Admail attribute mapping: If you do not want to mappore a certain attribute, you can use the `IGNORE = TRUE` in the @mapping annotation to mark the attribute. 2. Properties mapping configuration: In MapStructs, the configuration of attribute name mapping is achieved through the attributes annotated by @mapper.The following is a commonly used attribute configuration: -ComponentModel: Specify the type of dependent injection framework, such as Spring's @component, which can simplify the configuration of dependent injection. -MappedTargetPolicy: Specify a strategy of unable to mappore attributes, defaults to `reportingPolicy.error`, indicates that if there is an unspoiled attribute, it will generate a compilation error; it can also be set to` ReportingPolicy.ignore`, which means ignoring the attributes that have not been mapping. -Mappinginheritancestrategy: Specify the mapping inheritance strategy, the default is `auto_inherit_from_config`, indicating the mapping rules automatically inherited from other mapping methods. In addition, MapStruct also supports custom converters and formators for processing specific types of attribute mapping. Below is a simple example, which shows the use of MapStruct attribute name mapping: @Mapper public interface UserMapper { UserMapper INSTANCE = Mappers.getMapper(UserMapper.class); @Mapping(source = "name", target = "fullName") @Mapping(source = "age", target = "years") UserDTO userToUserDTO(User user); List<UserDTO> usersToUserDTOs(List<User> users); } In the above code, a UserMapper interface is defined to map the User class as UserDto class.In the USERTOUSERDTO method, the name property is specified to the FullName attribute through the @Mapping annotation, and the Age attribute is mapped to the year attribute.After using the Mapers.GetMapper method to obtain an instance of UserMapper, you can directly call the UsertouserDto method for conversion. Summarize: The attribute name mapping principle in the MapStruct Core framework is based on the attribute name of the source and the target class to generate the mapping code.Developers can configure the mapping relationship of different attribute names through @mapping annotations, or other configuration attributes can be used to control the mapping process.By using MapStruct reasonably, developers can simplify the workload of attribute mapping and improve the readability and performance of code.