Implementing Student Score Statistics with Fluent MyBatis, MyBatis, and MyBatis‑Plus

The author, a senior architect, introduces Fluent MyBatis, a Java API that enables building complex SQL without XML files, and compares it with native MyBatis and MyBatis‑Plus.

Database schema for the example student_score table:

create table `student_score` (
    id           bigint auto_increment comment '主键ID' primary key,
    student_id   bigint not null comment '学号',
    gender_man   tinyint default 0 not null comment '性别, 0:女; 1:男',
    school_term  int null comment '学期',
    subject      varchar(30) null comment '学科',
    score        int null comment '成绩',
    gmt_create   datetime not null comment '记录创建时间',
    gmt_modified datetime not null comment '记录最后修改时间',
    is_deleted   tinyint default 0 not null comment '逻辑删除标识'
) engine=InnoDB default charset=utf8;

The business requirement is to count, find the minimum, maximum, and average scores for the three subjects (English, Math, Chinese) in each term, only for records with a passing score (≥60) and with at least two samples.

Corresponding SQL statement:

select school_term,
       subject,
       count(score) as count,
       min(score) as min_score,
       max(score) as max_score,
       avg(score) as avg_score
from student_score
where school_term >= 2000
  and subject in ('英语','数学','语文')
  and score >= 60
  and is_deleted = 0
group by school_term, subject
having count(score) > 1
order by school_term, subject;

Fluent MyBatis implementation – using the fluent API to build the same query without XML. The author shows the generated code and IDE rendering, highlighting the concise expression.

Native MyBatis implementation – three steps are shown:

Define the mapper interface:

public interface MyStudentScoreMapper {
    List
> summaryScore(SummaryQuery paras);
}

Create the parameter class:

@Data
@Accessors(chain = true)
public class SummaryQuery {
    private Integer schoolTerm;
    private List
subjects;
    private Integer score;
    private Integer minCount;
}

Write the XML mapping:

<select resultType="map" parameterType="cn.org.fluent.mybatis.springboot.demo.mapper.SummaryQuery">
    select school_term,
           subject,
           count(score) as count,
           min(score) as min_score,
           max(score) as max_score,
           avg(score) as avg_score
    from student_score
    where school_term >= #{schoolTerm}
      and subject in
      <foreach collection="subjects" item="item" open="(" close=")" separator=",">
          #{item}
      </foreach>
      and score >= #{score}
      and is_deleted = 0
    group by school_term, subject
    having count(score) > #{minCount}
    order by school_term, subject
</select>

A test class demonstrates invoking the mapper:

@RunWith(SpringRunner.class)
@SpringBootTest(classes = QuickStartApplication.class)
public class MybatisDemo {
    @Autowired
    private MyStudentScoreMapper mapper;

    @Test
    public void mybatis_demo() {
        SummaryQuery paras = new SummaryQuery()
            .setSchoolTerm(2000)
            .setSubjects(Arrays.asList("英语","数学","语文"))
            .setScore(60)
            .setMinCount(1);
        List
> summary = mapper.summaryScore(paras);
        System.out.println(summary);
    }
}

MyBatis‑Plus implementation – the author shows a much shorter code snippet using the built‑in wrapper methods, but points out the heavy reliance on hard‑coded column strings.

Code generation settings for Fluent MyBatis:

public class AppEntityGenerator {
    static final String url = "jdbc:mysql://localhost:3306/fluent_mybatis_demo?useSSL=false&useUnicode=true&characterEncoding=utf-8";

    public static void main(String[] args) {
        FileGenerator.build(Abc.class);
    }

    @Tables(
        url = url, username = "root", password = "password",
        basePack = "cn.org.fluent.mybatis.springboot.demo",
        srcDir = "spring-boot-demo/src/main/java",
        daoDir = "spring-boot-demo/src/main/java",
        gmtCreated = "gmt_create", gmtModified = "gmt_modified", logicDeleted = "is_deleted",
        tables = @Table(value = {"student_score"})
    )
    static class Abc { }
}

Code generation settings for MyBatis‑Plus:

public class CodeGenerator {
    static String dbUrl = "jdbc:mysql://localhost:3306/fluent_mybatis_demo?useSSL=false&useUnicode=true&characterEncoding=utf-8";

    @Test
    public void generateCode() {
        GlobalConfig config = new GlobalConfig();
        DataSourceConfig dataSourceConfig = new DataSourceConfig();
        dataSourceConfig.setDbType(DbType.MYSQL)
            .setUrl(dbUrl)
            .setUsername("root")
            .setPassword("password")
            .setDriverName(Driver.class.getName());
        StrategyConfig strategyConfig = new StrategyConfig();
        strategyConfig
            .setCapitalMode(true)
            .setEntityLombokModel(false)
            .setNaming(NamingStrategy.underline_to_camel)
            .setColumnNaming(NamingStrategy.underline_to_camel)
            .setEntityTableFieldAnnotationEnable(true)
            .setFieldPrefix(new String[]{"test_"})
            .setInclude(new String[]{"student_score"})
            .setLogicDeleteFieldName("is_deleted")
            .setTableFillList(Arrays.asList(
                new TableFill("gmt_create", FieldFill.INSERT),
                new TableFill("gmt_modified", FieldFill.INSERT_UPDATE)));
        config
            .setActiveRecord(false)
            .setIdType(IdType.AUTO)
            .setOutputDir(System.getProperty("user.dir") + "/src/main/java/")
            .setFileOverride(true);
        new AutoGenerator().setGlobalConfig(config)
            .setDataSource(dataSourceConfig)
            .setStrategy(strategyConfig)
            .setPackageInfo(
                new PackageConfig()
                    .setParent("com.mp.demo")
                    .setController("controller")
                    .setEntity("entity")
            ).execute();
    }
}

Finally, the author summarizes the three approaches, noting that Fluent MyBatis offers a balanced API with type safety, native MyBatis is verbose, and MyBatis‑Plus is concise but prone to string‑based errors, helping readers decide which tool fits their project.