Spring Controller 使用 RequestBody 作为一些 DTO 列表的补丁操作

Question

I have list of DTOs as requestbody to spring controller which is a patch operation. The patching looks starightforward,

--> I would iterate over the list

--> Get each DTO

--> Get the entity object returned by findOne(id) method of JPA

--> Now here I have a problem, which is checking if the field value is not null, then set it to the entity, otherwise do nothing

--> I didn't want to check null value for each field and set it to the attached entity, so I used ModelMapper here. Please find the below code

        ModelMapper modelMapper = new ModelMapper();
        modelMapper.getConfiguration().setPropertyCondition(Conditions.isNotNull());
        modelMapper.map(someDO, someEntity);  //someEntity is the one returned by findOne
        tltMasterRepository.save(someEntity);

--> The problem with the null value is solved. I would not have to explicitly check for null values before setting it to the attached entity.

--> But I have a few more requirements now. For a few fields I wanted to perform some operation and derive some value before setting it to the attached entity. For example.. someDo.username & someEntity.userID
I had to get the username, call a utility method to get the userID from the username and then set this userID value to someEntity.userID.

Similarly I have a few more fields where I have to do some pre-processing before setting it to the entity?

What is the best way I can do that?

Answer 1

Take a look at Converter . With convert you can extract userId from user name and set it to entity:

ModelMapper modelMapper = new ModelMapper();
modelMapper.getConfiguration().setPropertyCondition(Conditions.isNotNull());    
Converter<String, String> userIdConverter = ctx -> ctx.getSource() == null ? null : Utils.extractUserId(ctx.getSource());
modelMapper.typeMap(SomeDO.class, SomeEntity.class).addMappings(mapper -> mapper.using(userIdConverter).map(SomeDO::getUsername, SomeEntity::setUserId));
modelMapper.map(someDO, someEntity);
tltMasterRepository.save(someEntity);

Answer 2

You can use the java bean validation with the DTO class and use @Valid @RequestBody , for more details check out https://www.baeldung.com/javax-validation