例如需要在controller提供一个分页查询的API接口,代码可以这么写:
@RequestMapping("/list")
@ResponseBody
public Object list(int pageNo, int pageSize, String name) throws Exception {
Page<User> page = userService.selectPage(pageNo, pageSize, new SelectWrapper<User>()
.eqNotBlank(User::getName, name)
.eq(User::getDeleted, false)
.orderByDesc(User::getId)
);
return page;
}curl http://localhost:8080/list?pageNo=1&pageSize=10
-> SELECT * FROM `user` WHERE `deleted` = false ORDER BY `id` DESC LIMIT 0,10
curl http://localhost:8080/list?pageNo=1&pageSize=10&name=name
-> SELECT * FROM `user` WHERE `name` = 'name' AND `deleted` = false ORDER BY `id` DESC LIMIT 0,10
this.userService.selectMap(new SelectWrapper<User>()
.select(SqlFunction.count(SqlFunction.distinct(User::getId), "userCount"),
SqlFunction.min(User::getAge, VoInfo::getMinAge),
SqlFunction.max(User::getAge, VoInfo::getMaxAge))
.eq(User::getAge, 20)
);
SELECT COUNT(DISTINCT(`id`)) AS 'userCount',MIN(`age`) AS 'minAge',MAX(`age`) AS 'maxAge'
FROM `user` WHERE `age` = ?
long dbCount = this.userService.selectCount(new SelectWrapper<User>()
.eqNested(User::getAge, t -> t.applySelectWrapper(User.class)
.select(User::getAge)
.eq(User::getAge, randomAge)
.limit(1)
)
.eq(User::getFlag, flag)
);
SELECT COUNT(*) FROM `user` WHERE `age` = (SELECT `age` FROM `user` WHERE `age` = ? LIMIT 1) AND `flag` = ?
List<JoinResultVO> list = this.studentService.selectObjectList(JoinResultVO.class, new SelectJoinWrapper<Student>()
.select(Student::getName)
.selectAs(TeacherInfo::getName, JoinResultVO::getTeacherName)
.selectAs(Student::getName, JoinResultVO::getStudentName)
.selectAs(CourseInfo::getName, JoinResultVO::getCourseName)
.leftJoin(CourseInfo.class, CourseInfo::getId, Student::getId)
.rightJoin(TeacherInfo.class, TeacherInfo::getId, CourseInfo::getTeacherId)
.eq(Student::getDeleted, false)
.eq(CourseInfo::getDeleted, false)
);
SELECT t1.`name` ,t3.`name` AS 'teacherName' ,t1.`name` AS 'studentName' ,t2.`name` AS 'courseName'
FROM `student` t1
LEFT JOIN course_info t2 ON t2.`id` = t1.`id`
LEFT JOIN teacher_info t3 ON t3.`id` = t2.`teacher_id`
WHERE t1.`deleted` = ? AND t2.`deleted` = ?
this.userService.update(new UpdateWrapper<User>()
.setDiySql(User::getAge, t -> t.applyDiySqlWrapper(User.class)
.setExpression("{} - {} + 10")
.setColumns(User::getId, User::getUserGrade))
.eq(User::getFlag, flag)
);
UPDATE `user` SET `age` = (`id` - `user_grade` + 10) WHERE `flag` = ?
this.userService.selectCount(new SelectWrapper<User>()
.andDiySql(t -> t.applyDiySqlWrapper(User.class)
.setExpression("{} > {} + 100")
.setColumns(User::getId, User::getAge))
.eq(User::getFlag, flag)
);
SELECT COUNT(*) FROM `user` WHERE (`id` > `age` + 100) AND `flag` = ?
<!-- https://mvnrepository.com/artifact/io.github.happytimor/mybatis-helper-core -->
<dependency>
<groupId>io.github.happytimor</groupId>
<artifactId>mybatis-helper-core</artifactId>
<version>1.0.11</version>
</dependency>public class User {
private Integer id;
private String realName;
private Boolean deleted;
//getter & setter
}public interface UserMapper extends BaseMapper<User> {
//不需要写任何方法
}@Service
public class UserService extends BaseService<UserMapper, User> {
//不需要写任何方法
}@Component
public class MyHelper extends MybatisHelper implements InitializingBean {
@Override
public void afterPropertiesSet() {
//指定mapper所在包路径
this.registSingleDatabase("io.github.happytimor.test.mapper");
}
}全部配置已完成,可以愉快的增删改查了。
- 不需要写任何xml文件,即可完成最基本的增删改查操作
- 没有修改任何mybatis源码，也没有覆盖原先方法,只是做了简单的方法注入
- 与既有xml文件的方法不会冲突(如果方法名已存在则跳过此方法的注入)
- 支持多数据源以及动态数据源
- 支持分表查询(例如: user_01), 支持无主键表
- 支持join操作
- 全程lambda表达式链式调用 (需要jdk1.8+)
- 自动对数据库字段进行包裹(例如:
order)
有问题请发邮件到我的邮箱: [email protected]
