Mybatis plus 通用Mapper

原创已于 2023-04-15 10:48:40 修改 · 572 阅读

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文章标签：

#mybatis #java #spring boot

于 2023-04-15 10:40:13 首次发布

文章介绍了如何集成Mybatis-Plus，包括引入相关依赖、创建实体类、定义Mapper接口、启动类配置扫描以及注解的使用。还详细讲解了分页拦截器的配置和测试。

一、导入相应依赖

 <!--mybatis plus 启动器-->
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>3.5.2</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.31</version>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid-spring-boot-starter</artifactId>
            <version>1.1.10</version>
        </dependency>

二、创建实体类

package com.qf.day0414mybatisplus.entity;

import lombok.Data;

@Data//小辣椒插件data表示已经有getsettoStiring方法了
public class User {
    private Integer id;
    private String name;
    private Integer age;
    private String email;
}

三、创建Mapper去继承BaseMapper（service层去继承IService 且二者查询方法不一样）

package com.qf.day0414mybatisplus.dao;

import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.qf.day0414mybatisplus.entity.User;

public interface UserDao extends BaseMapper<User> {
}

四、在启动类上指定要变成实现类德接口所在的包

@MapperScan(value = {"com.qf.day0414mybatisplus.dao","com.qf.day0414mybatisplus.mapper"})

五、在测试类中

    @Autowired
    private UserDao userDao;


    @Test
    void contextLoads() {

        List<User> users = userDao.selectList(null);

        System.out.println(users );
    }

六、注解使用

@TableName

描述：表名注解，表示实体类对应德表

使用位置：实体类

@TableName("sys_user")
public class User {
    private Long id;
    private String name;
    private Integer age;
    private String email;
}

@TableId

描述：主键注解

使用位置：实体类主键字段

@TableName("sys_user")
public class User {
    @TableId
    private Long id;
    private String name;
    private Integer age;
    private String email;
}

@TableField

描述：字段注解（非主键）

@TableName("sys_user")
public class User {
    @TableId
    private Long id;
    @TableField("nickname")
    private String name;
    private Integer age;
    private String email;
}

七、补充分析

分页设置

需在启动类上写一个拦截器

package com.qf.day0414mybatisplus;

import com.baomidou.mybatisplus.annotation.DbType;
import com.baomidou.mybatisplus.extension.plugins.MybatisPlusInterceptor;
import com.baomidou.mybatisplus.extension.plugins.inner.PaginationInnerInterceptor;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;

@SpringBootApplication
@MapperScan(value = {"com.qf.day0414mybatisplus.dao","com.qf.day0414mybatisplus.mapper"})
public class Day0414mybatisplusApplication {

    public static void main(String[] args) {
        SpringApplication.run(Day0414mybatisplusApplication.class, args);
    }



//分页拦截器
    @Bean
    public MybatisPlusInterceptor mybatisPlusInterceptor() {
        MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor();


        interceptor.addInnerInterceptor(new PaginationInnerInterceptor(DbType.MYSQL));

        return interceptor;
    }

}

测试

    @Test
    void page(){

        Page<Student> page = new Page<>(1, 2);
        Page<Student> page1 = iStudentService.page(page);
        List<Student> records = page1.getRecords();
        System.out.println(records);


    }