spring-boot - Orika Mapper-MapperFacade初始化后无法注册转换器

Question

我创建了一个类，用于在 Spring 启动应用程序中使用Orika Mapper API复制bean属性，如下所示:

public class ObjectMapper {

    private static MapperFactory mapperFactory = new DefaultMapperFactory.Builder().build();

    public static ClientEntity toClientEntity(ClientDTO clientDTO) {
        BoundMapperFacade<ClientDTO, ClientEntity> boundMapper = mapperFactory.getMapperFacade(ClientDTO.class, ClientEntity.class);
        return boundMapper.map(clientDTO);
    }   

    public static UserEntity toUserEntity(UserDTO userDTO) {
        mapperFactory.getConverterFactory().registerConverter(new PassThroughConverter(LocalDate.class));
        mapperFactory.getConverterFactory().registerConverter(new PassThroughConverter(LocalTime.class));
        BoundMapperFacade<UserDTO, UserEntity> boundMapper = mapperFactory.getMapperFacade(UserDTO.class, UserEntity.class);
        return boundMapper.map(userDTO);
    }
}

UserEntity和UserDTO POJO类具有JAVA 8 LocalDate和LocalTime属性，因此具有针对mapperFactory的registeredConverters。第一次可以正常工作，但在连续调用时会抛出以下异常:

java.lang.IllegalStateException: Cannot register converters after MapperFacade has been initialized
    at ma.glasnost.orika.converter.DefaultConverterFactory.registerConverter(DefaultConverterFactory.java:192) ~[orika-core-1.4.6.jar:na]
    at ma.glasnost.orika.impl.DefaultMapperFactory$ConverterFactoryFacade.registerConverter(DefaultMapperFactory.java:1614) ~[orika-core-1.4.6.jar:na]

我了解这是因为在初始化MapperFacade之后正在注册转换器。如何解决这个问题？初始化前如何注册转换器？

Answer 1

在提供的代码段中，您每次尝试调用toUserEntity()时都尝试注册转换器。因此，第一个调用将起作用，但是第二个调用将失败，因为MapperFacade在第一个调用期间已被初始化。

您可以像这样将转换器注册从映射方法移动到静态块:

private static MapperFactory mapperFactory = new DefaultMapperFactory.Builder().build();
static {
    mapperFactory.getConverterFactory().registerConverter(new PassThroughConverter(LocalDate.class));
    mapperFactory.getConverterFactory().registerConverter(new PassThroughConverter(LocalTime.class));
}

另外，您可能希望将BoundMapperFacade移到静态字段，以避免不必要的getMapperFacade调用，如下所示:

private static BoundMapperFacade<ClientDTO, ClientEntity> clientBoundMapper 
                     = mapperFactory.getMapperFacade(ClientDTO.class, ClientEntity.class);
private static BoundMapperFacade<UserDTO, UserEntity> userBoundMapper 
                     = mapperFactory.getMapperFacade(UserDTO.class, UserEntity.class);

因此，映射方法将变成简单的一列式:

public static ClientEntity toClientEntity(ClientDTO clientDTO) {
    return clientBoundMapper.map(clientDTO);
}   

public static UserEntity toUserEntity(UserDTO userDTO) {
    return userBoundMapper.map(userDTO);
}