1、创建springboot项目

2、引入依赖

<dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter</artifactId>
</dependency>
<dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-test</artifactId><scope>test</scope>
</dependency>
<dependency><groupId>com.baomidou</groupId><artifactId>mybatis-plus-boot-starter</artifactId><version>3.5.1</version>
</dependency>
<dependency><groupId>org.projectlombok</groupId><artifactId>lombok</artifactId><optional>true</optional>
</dependency>
<dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><scope>runtime</scope>
</dependency>

3、引入插件

File——Settings——Plugins——lombok（设置过就不用设置了）

4.设置application.yml文件

spring:# 配置数据源信息datasource:# 配置数据源类型type: com.zaxxer.hikari.HikariDataSource# 配置连接数据库信息driver-class-name: com.mysql.cj.jdbc.Driverurl: jdbc:mysql://localhost:3306/mybatis_plus?serverTimezone=GMT%2B8&characterEncoding=utf-8&useSSL=falseusername: rootpassword: 123456# 加入日志功能
mybatis-plus:configuration:log-impl: org.apache.ibatis.logging.stdout.StdOutImpl# 配置类型别名所对应的包type-aliases-package: com.example.demos.entity

本案例测试类使用的是user

如果测试需要加注解

@SpringBootTest
public class MybatisPlusTest {@Resourceprivate UserMapper userMapper;//报错，mapper层加@Repository注解@Testpublic void testSelectList(){List<User> userList = userMapper.selectList(null);for (User user : userList) {System.out.println(user);}}
}

此时准备工作已经做完

使用分页插件查询

首先建一个配置类

@Configuration
@MapperScan("com.example.demos.mapper")
public class MybatisPlusConfig {@Beanpublic MybatisPlusInterceptor mybatisPlusInterceptor(){MybatisPlusInterceptor mybatisPlusInterceptor = new MybatisPlusInterceptor();mybatisPlusInterceptor.addInnerInterceptor(new PaginationInnerInterceptor(DbType.MYSQL));return mybatisPlusInterceptor;}
}

第二步测试类中调用selectPage

@SpringBootTest
public class MybatisPlusPageTest {@Autowiredprivate UserMapper userMapper;@Testpublic void testPage(){Page<User> page = new Page<>(1,5);//limit （起始数，几条）1指第1页Page<User> userPage = userMapper.selectPage(page, null);//null查询全部就用nullSystem.out.println(page);System.out.println(page.getRecords());//获取当前页的数据System.out.println(page.getTotal());//查询总条数System.out.println(page.hasNext());//是否有下一页System.out.println(page.hasPrevious());//是否有上一页}
}

自定义分页功能

配置类和上面一样

首先在mapper层，写方法

@Repository
public interface UserMapper extends BaseMapper<User> {//Page必须位于第一个参数Page<User> selectPageVo(@Param("page")Page<User> page,@Param("age") Integer age);
}

resource下的mapper中的xml文件

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapperPUBLIC "-//mybatis.org//DTD Mapper 3.0//EN""http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.example.demos.mapper.UserMapper">
<!--    Page<User> selectPageVo(@Param("page")Page<User> page,@Param("age") Integer age);--><select id="selectPageVo" resultType="User">select * from user where age > #{age}</select>
</mapper>

测试类中

@Test
public void testByPage(){Page<User> page = new Page<>(1,2);userMapper.selectPageVo(page,20);//第二个参数是拼接在SQL里的参数，也是前端传来的System.out.println(page.getRecords());//获取当前页的数据System.out.println(page.getTotal());//查询总条数System.out.println(page.hasNext());//是否有下一页System.out.println(page.hasPrevious());//是否有上一页
}