Source-target mapping strategy analysis in the MapStruct Core framework

Source in the MapStruct Core framework-target mapping strategy analysis MapStruct is a Java annotation processor framework that is used to realize the attributes of one Java class to another Java class.In MAPSTRUCT, the source-target mapping strategy is to specify how to map the attributes of one class to the rules and methods of the attributes of another class. Source-target mapping strategy is defined in the mapping interface of Mapstruct.This interface specifies the mapping rules by annotating.In this interface, different annotations can be used to describe the mapping relationship between attributes.For example, using the `@Mapping` annotation can specify the attribute mapping between the source type and the target type.You can also use `@mappings` annotations to combine multiple`@Mapping` annotations to define complex mapping rules. The following is an example code that uses the MAPSTRUCT framework to implement the source-target mapping strategy: public class Source { private String name; private int age; // getters and setters } public class Target { private String fullName; private int years; // getters and setters } @Mapper public interface SourceTargetMapper { SourceTargetMapper INSTANCE = Mappers.getMapper(SourceTargetMapper.class); @Mappings({ @Mapping(source = "name", target = "fullName"), @Mapping(source = "age", target = "years") }) Target sourceToTarget(Source source); } In the above example, we have a `source` class and a` target` class, which have different attribute names.We define an `SourceTargetMapper` interface and use the`@Mapper` annotation mark on the interface. This is a mapping interface.In the `SourceTargetMapper` interface, we define a method` SourceTotarget` to map the `Source` object to the` target` object. By using the `Source` and` target` attributes in the `@mapping` annotations, we specify the attribute mapping relationship between the source type and the target type.In this example, we map the `name` attribute to the` fullname` attribute, and the `Age` attribute to the` Years` property. To use the mapper, we can call the `SourceTargetMapper.instance.sourceTotarget (source) method to perform the mapping operation.This will map the attribute values of the `Source` object to the corresponding properties of the` Target` object in the interface. In order to take effect on the above code, some configurations need to be performed.First, we need to add MapStruct dependency items to the construction configuration of the project.For example, if maven is used to build, you need to add the following dependencies to the `pom.xml` file: <dependencies> <dependency> <groupId>org.mapstruct</groupId> <artifactId>mapstruct</artifactId> <version>1.4.2.Final</version> </dependency> </dependencies> Then, you need to configure the MapStruct annotation processor to generate the implementation code of the target-target mapping during compilation.For Maven project, you can add the following plug -in configuration under the `build` element of the` pom.xml` file: <plugins> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-compiler-plugin</artifactId> <version>3.8.1</version> <configuration> <annotationProcessorPaths> <path> <groupId>org.mapstruct</groupId> <artifactId>mapstruct-processor</artifactId> <version>1.4.2.Final</version> </path> </annotationProcessorPaths> </configuration> </plugin> </plugins> Through the above configuration, MapStruct will automatically generate the implementation code of the `SourceTargetMapperimpl` class, which contains the specific implementation of the source-target mapping strategy. In summary, the source-target mapping strategy in the Mapstruct Core framework is defined by using annotations on the mapping interface.These annotations specify the mapping relationship between attributes and generate implementation code during compilation.By correcting the dependency item and the annotation processor, you can easily use the mapping operation of the source-target attribute.