Two Weeks into My Internship

I’ve spent two weeks working on the Spring Boot backend at a company in Hangzhou. I’ve found plenty of gaps in what I know, and a few things worth writing down.

When I started the job, I was pretty new to Spring Boot. I knew a few basics, and I’d never even used MyBatis...

At first I tried writing endpoints on my own, working from a template. Then I’d look at my coworkers’ code and go back and revise mine. By now I’d say I’ve more or less got the hang of writing basic CRUD endpoints.

I keep coming across ways to write the same thing that feel easier or more flexible. I suspect they each suit different situations, and sometimes it makes sense to use them together.

# Starting out

First I learned to do CRUD operations with MyBatis. I could write the SQL in an XML file:

<select id="function_name" resultType="java.util.Map">

    select * from table_name

</select>

Or put an annotation directly above a method in the DAO layer:

@Select("select * from table_name")

// or

@Insert("insert into table_name (id, field_name) values (#{id}, #{function_variable_name})")

# What came next

Then I discovered MyBatis-Plus. Its generic service interface, IService , and mapper interface, BaseMapper , give you quite a few CRUD methods you can call without writing SQL:

public interface ServiceName extends IService<EntityName> {}

public class ServiceImplName extends ServiceImpl<DaoName, EntityName>

        implements ServiceName {}

// and

@Mapper

public interface DaoName extends BaseMapper<EntityName> {}

For queries, I still had to build the conditions with a QueryWrapper :

QueryWrapper<EntityName> queryWrapper = new QueryWrapper<>();

queryWrapper.eq(String column, Object val);

# Where I am now

Now I know I can combine the two approaches.

For something simple, like reading data from a few tables, I can write the query directly in XML or use an annotation.

When I need CRUD operations, I use the generic types from MyBatis-Plus. If I need something they don’t provide, I can extend what’s already there:

• Add the corresponding method to the service layer.
• If it needs to talk to the database, add a method to the DAO layer.

A few other things I’ve picked up along the way:

• Put constants and shared routines in the relevant Common... helpers so they’re ready to use wherever they’re needed.

• It’s worth looking through utils . Chances are some of the things I need already exist there.

  There’s Result for endpoint return values, FileUpload for uploads, PageUtils for pagination, UserInfoUtil for getting the user ID...

  The names might differ from project to project, but the jobs are much the same. I don’t have to write them all myself.

• ...

Back to learning. Maybe one day I’ll write clean, simple code.