前言
MyBatis-Plus (opens new window)（简称 MP）是一个 MyBatis (opens new window)的增强工具，在 MyBatis 的基础上只做增强不做改变，为简化开发、提高效率而生。
框架结构：
1、添加依赖
<dependency> <groupId>com.baomidou</groupId> <artifactId>mybatis-plus-boot-starter</artifactId> <version>3.5.2</version> </dependency>
2、配置数据库连接
spring: datasource: username: root password: root url: jdbc:mysql://127.0.0.1:3306/spring driver-class-name: com.mysql.cj.jdbc.Driver
3、使用BaseMapper接口
3.1、创建表和数据
DROP TABLE IF EXISTS user; CREATE TABLE user ( id BIGINT(20) NOT NULL COMMENT '主键ID', name VARCHAR(30) NULL DEFAULT NULL COMMENT '姓名', age INT(11) NULL DEFAULT NULL COMMENT '年龄', email VARCHAR(50) NULL DEFAULT NULL COMMENT '邮箱', PRIMARY KEY (id) );
DELETE FROM user; INSERT INTO user (id, name, age, email) VALUES (1, 'Jone', 18, 'test1@baomidou.com'), (2, 'Jack', 20, 'test2@baomidou.com'), (3, 'Tom', 28, 'test3@baomidou.com'), (4, 'Sandy', 21, 'test4@baomidou.com'), (5, 'Billie', 24, 'test5@baomidou.com');
3.2、定义mapper
/** * 定义mapper类 */ public interface UserMapper extends BaseMapper<User>{ @Insert("<script>insert into user(name,age,email) values\n" + " <foreach collection=\"list\" item=\"user\" separator=\",\">\n" + " (#{user.name},#{user.age},#{user.email})\n" + " </foreach>\n" + " </script>") int batchInsertUser(List<User> userList); }
3.3、定义service
/** * 用户信息服务类 */ public interface UserService { /** * 插入用户信息 * @param user * @return */ int insertUser(User user); /** * 批量插入用户信息 * @param userList * @return */ int batchInsertUser(List<User> userList); /** * 更新用户信息 * @param user * @return */ int updateUser(User user); /** * 删除用户信息 * @param user * @return */ int deleteUser(User user); /** * 批量删除用户信息 * @param ids * @return */ int batchDeleteUser(List<Integer> ids); /** * 查询用户信息列表 * @return */ List<User> selectUser(); }
@Service public class UserServiceImpl implements UserService { @Autowired private UserMapper userMapper; @Override public int insertUser(User user) { return this.userMapper.insert(user); } @Override public int batchInsertUser(List<User> userList) { return this.userMapper.batchInsertUser(userList); } @Override public int updateUser(User user) { return this.userMapper.updateById(user); } @Override public int deleteUser(User user) { return this.userMapper.deleteById(user); } @Override public int batchDeleteUser(List<Integer> ids) { return this.userMapper.deleteBatchIds(ids); } @Override public List<User> selectUser(User user) { QueryWrapper<User> userQueryWrapper = new QueryWrapper<>(); //模糊查询 userQueryWrapper.like(user.getName()!=null,"name",user.getName()); //精确查询 userQueryWrapper.eq(user.getEmail()!=null,"email",user.getEmail()); //范围查询 userQueryWrapper.between(user.getAge() != null,"age",20,50); //排序 userQueryWrapper.orderByAsc("age"); return this.userMapper.selectList(userQueryWrapper); } }
4、plus分页
4.1、添加依赖
<dependency> <groupId>org.apache.commons</groupId> <artifactId>commons-lang3</artifactId> <version>3.12.0</version> </dependency>
4.2、添加配置
@Configuration public class MybatisPlusConfig { @Bean public MybatisPlusInterceptor mybatisPlusInterceptor(){ MybatisPlusInterceptor mybatisPlusInterceptor = new MybatisPlusInterceptor(); mybatisPlusInterceptor.addInnerInterceptor(new PaginationInnerInterceptor(DbType.MYSQL)); return mybatisPlusInterceptor; } }
4.3、编写分页代码
@Override public IPage<User> selectUserPagination(PageDTO<User> pageDTO) { //传递当前页和页记录数 IPage<User> iPage = new Page<>(pageDTO.getCurrentPage(),pageDTO.getPageSize(),true); QueryWrapper<User> userQueryWrapper = new QueryWrapper<>(); //查询条件 User queryUser = pageDTO.getT(); if(queryUser != null){ //模糊查询 userQueryWrapper.like(queryUser.getName()!=null,"name",queryUser.getName()); //精确查询 userQueryWrapper.eq(queryUser.getEmail()!=null,"email",queryUser.getEmail()); //范围查询 userQueryWrapper.between(queryUser.getAge() != null,"age",20,50); //排序 userQueryWrapper.orderByAsc("age"); } return this.page(iPage, userQueryWrapper); }
4.4、分页单元测试类
@Test void testPagination(){ QueryDTO<QueryUserDTO> queryUserDTOQueryDTO = new QueryDTO<>(); queryUserDTOQueryDTO.setCurrentPageNo(1); queryUserDTOQueryDTO.setPageSize(10); QueryUserDTO queryUserDTO = new QueryUserDTO(); //queryUserDTO.setName("tiger"); queryUserDTO.setBeginAge(60); queryUserDTO.setEndAge(100); //queryUserDTO.setEmail("333@qq.com37"); queryUserDTOQueryDTO.setT(queryUserDTO); System.out.println("############json: " + JSON.toJSONString(queryUserDTOQueryDTO, JSONWriter.Feature.PrettyFormat)); System.out.println("############json: " + JSON.toJSONString(this.userService.selectUserPagination(queryUserDTOQueryDTO), JSONWriter.Feature.PrettyFormat)); }
5、逻辑删除
5.1、表新增字段
ALTER TABLE `tb_user` ADD COLUMN `deleted` INT(1) NULL DEFAULT 0 COMMENT '1代表删除，0代表未删除';
5.2、实体类
/** * 1 逻辑删除 0 正常 */ @TableLogic private Integer deleted;
5.3、配置文件
mybatis-plus: configuration: log-impl: org.apache.ibatis.logging.stdout.StdOutImpl #开启sql日志 global-config: db-config: logic-delete-value: 1 # 逻辑已删除值(默认为 1) logic-not-delete-value: 0 # 逻辑未删除值(默认为 0)
5.4、自动填充审计字段
5.4.1、新增字段
5.4.2、实体类修改
/** * 插入时间 */ @TableField(fill = FieldFill.INSERT) private LocalDateTime createTime; /** * 更新时间 */ @TableField(fill = FieldFill.UPDATE) private LocalDateTime updateTime;
5.4.3、实现MetaObjectHandler接口
/** * 元对象处理器 */ @Component public class MBMetaObjectHandler implements MetaObjectHandler { @Override public void insertFill(MetaObject metaObject) { this.fillStrategy(metaObject, "createTime",LocalDateTime.now()); } @Override public void updateFill(MetaObject metaObject) { this.fillStrategy(metaObject, "updateTime",LocalDateTime.now()); } }
