为什么用单Mapper模式？

1：更省事，不需要一个个写Mapper

2：更省内存，如果你有1000个表，那可以省1000个类以及1000 * N 个方法，可能可多；对于mybatis来说，能更快的匹配到对应的执行方法

1：引入maven依赖

<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>cn.mybatis-mp</groupId>
            <artifactId>mybatis-mp-spring-boot-parent</artifactId>
            <version>1.7.7-RC5</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>
    </dependencies>
</dependencyManagement>

<dependencies>
    <dependency>
        <groupId>cn.mybatis-mp</groupId>
        <artifactId>mybatis-mp-spring-boot-starter</artifactId>
    </dependency>
</dependencies>

2：配置mybatis-mp启动项

@MapperScan(basePackageClasses = BasicMapper.class , annotationClass = Mapper.class)

3：增删改查，丝滑流畅，简单方便

引入Mapper

@Autowired
private BasicMapper basicMapper;

3.1：查询

AppVersion appVersion = basicMapper.getById(AppVersion.class , 1);

List<AppVersion> list= QueryChain.of(basicMapper,AppVersion.class)
    .eq(AppVersion::getId,1)
    .like(AppVersion::getName,"xx")
    .list();

Pager<AppVersion> page= QueryChain.of(basicMapper,AppVersion.class)
    .eq(AppVersion::getId,1)
    .like(AppVersion::getName,"xx")
    .paging(Pager.of(1,10));

3.2：删除

basicMapper.delete(appVersion);

basicMapper.deleteById(AppVersion.class , 1);

basicMapper.delete(AppVersion.class, where -> where.eq(AppVersion::getId,1))

3.3：改

basicMapper.update(appVersion)

3.4：新增

basicMapper.save(appVersion)

3.5：如果想在XML里写也很简单

<mapper namespace="cn.mybatis.mp.core.mybatis.mapper.BasicMapper">
    <select id="SysRole:basicXmlPaging" resultType="com.mybatis.mp.core.test.DO.SysRole">
        select *
        from sys_role
        where id >= #{id}
          and id &lt;= #{id2}
        order by id asc
    </select>
</mapper>

List<SysRole> list = sysRoleMapper.getBasicMapper().withSqlSession(".SysRole:basicXmlPaging", new HashMap() {{
      put("id", 1);
      put("id2", 2);
  }},(statement, params, sqlSession) -> {
      return sqlSession.selectList(statement, params);
});

​4:其他还有很多很丰富的api，请前往官网 https://mybatis-mp.cn