框架

MyBatis-plus

概述

是一个Mybatis的增强工具，在Mybatis的基础上只做增强，不做改变。目的就是简化Mybatis的操作

使用

  1. 添加依赖

    <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>3.5.3</version>
        </dependency>

  2. 数据源配置

    spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3306/mydb?useUnicode=true&characterEncoding=utf8&serverTimezone=Asia/Shanghai
spring.datasource.username=root
spring.datasource.password=root
###日志配置设置
mybatis-plus.configuration.log-impl=org.apache.ibatis.logging.stdout.StdOutImpl

# mapper存储位置配置
mybatis-plus.mapper-locations=classpath:/mapper/**/*.xml

  3. 实体类

    @Data
@TableName("dept")
public class Dept {
    @TableId
    private Integer deptno;
    private String dname;
    private String loc;
}

  4. mapper接口

    public interface DeptMapper extends BaseMapper<Dept> {

}

  5. 测试

    @SpringBootTest
class MybatisplusDemoApplicationTests {
    @Autowired
    private DeptMapper deptMapper;
    @Test
    public void testGetById(){
        Dept dept = deptMapper.selectById(10);
        System.out.println(dept);
    }
    @Test
    public void getAll(){
        QueryWrapper<Dept> queryWrapper = new QueryWrapper<>();
        List<Dept> list = deptMapper.selectList(queryWrapper);
        System.out.println(list);
    }

    @Test
    public void getDepts(){
        QueryWrapper<Dept> queryWrapper = new QueryWrapper<>();
        queryWrapper
                .in("deptno",30,40,50)
//                .ge("deptno",50)
//                .eq("dname","hr")
//                .like("loc","s")
                                    ;
        List<Dept> list = deptMapper.selectList(queryWrapper);
        System.out.println(list);
    }

    @Test
    public void testInsert(){
        int i = deptMapper.insert(new Dept(null, "销售部", "北京"));
        System.out.println(i);
    }

    @Test
    public void testUpdate(){
        Dept dept = new Dept(105, "销售部", "上海");
        int i = deptMapper.updateById(dept);
        System.out.println(i);
    }
}

实体关联

  1. 修改实体类

    @Data
@AllArgsConstructor
@NoArgsConstructor
@TableName("emp")
public class Emp {
    @TableId(type = IdType.AUTO)
    private Integer empno;
    private String ename;
    private String job;
    private Date hiredate;
    private Double sal;
    private Integer mgr;
    private Double comm;
    private Integer deptno;
    @TableField(exist = false)
    private Dept dept;

}

  2. 编写mapper接口

    public interface EmpMapper extends BaseMapper<Emp> {
    @Override
    @ResultMap("baseMap")
    @Select("select * from emp where empno = #{empno}")
    Emp selectById(Serializable id);
}

  3. 编写mapper.xml

    //mapper/EmpMapper.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" >
<mapper namespace="com.neu.mybatisplus_demo.mapper.EmpMapper">
    <resultMap id="baseMap" type="com.neu.mybatisplus_demo.entity.Emp">
        <association property="dept" column="deptno" select="com.neu.mybatisplus_demo.mapper.DeptMapper.selectById"></association>
    </resultMap>
</mapper>

  4. 修改application.properties

    # mapper存储位置配置
mybatis-plus.mapper-locations=classpath:/mapper/**/*.xml

分页

  1. 添加一个分页插件拦截器

    @Configuration
public class MybatisplusConfig {

    @Bean
    public MybatisPlusInterceptor mybatisPlusInterceptor(){
        MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor();
        interceptor.addInnerInterceptor(new PaginationInnerInterceptor());
        return interceptor;
    }
}

  2. 测试

    @Test
    public void testPage(){
        Page<Dept> deptPage = new Page<>(2,3);
        QueryWrapper<Dept> queryWrapper = new QueryWrapper<>();
        Page<Dept> deptPage1 = deptMapper.selectPage(deptPage, queryWrapper);
        System.out.println(deptPage1.getRecords());//当前页数据
        System.out.println(deptPage1.getTotal());//总行数
        System.out.println(deptPage1.getPages());//总页数
    }

业务逻辑层

  1. 接口

    public interface DeptService extends IService<Dept> {
}

  2. 实现类

    @Service
public class DeptServiceImpl extends ServiceImpl<DeptMapper,Dept> implements DeptService {

}

  3. 测试

    @Autowired
private DeptService deptService;
   
@Test
public void deptServiceGetById(){
    Dept byId = deptService.getById(10);
    System.out.println(byId);
}
   
@Test
public void deptServiceGetAll(){
    List<Dept> list = deptService.list();
    System.out.println(list);
}
   
@Test
public void deptServiceGetByPaged(){
    Page<Dept> page = deptService.page(new Page<>(2, 5), new QueryWrapper<>());
    System.out.println(page);
    System.out.println(page.getRecords());
    System.out.println(page.getTotal());
    System.out.println(page.getPages());
}
@Test
public void deptServiceInsert(){
    boolean b = deptService.save(new Dept(null, "鱼长梦短", "IGXE"));
    System.out.println(b);
}
   
@Test
public void deptServiceUpdate(){
    boolean b = deptService.updateById(new Dept(106, "元女王", "IGXE"));
    System.out.println(b);
}
   
@Test
public void deptServiceDelete(){
    boolean b = deptService.removeById(106);
    System.out.println(b);
}

控制器代码生成

  1. 添加依赖

    <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-generator</artifactId>
            <version>3.5.3</version>
        </dependency>

        <!-- Velocity 模板引擎，用于生成代码 -->
        <dependency>
            <groupId>org.apache.velocity</groupId>
            <artifactId>velocity-engine-core</artifactId>
            <version>2.3</version>
        </dependency>

  2. 添加模板

    package ${package.Controller};

import ${package.Entity}.${entity};
import ${package.Service}.${entity}Service;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;

import java.util.List;

@RestController
@RequestMapping("/api/${entity}")
public class ${entity}Controller {

    private ${entity}Service ${entity.toLowerCase()}Service;

    @Autowired
    public void set${entity}Service(${entity}Service ${entity.toLowerCase()}Service) {
        this.${entity.toLowerCase()}Service = ${entity.toLowerCase()}Service;
    }

    // 创建（Create）
    @PostMapping("/create")
    public String create(@RequestBody ${entity} ${entity.toLowerCase()}) {
            ${entity.toLowerCase()}Service.save(${entity.toLowerCase()});
        return "Created successfully";
    }

    // 读取（Read）
    @GetMapping("/get/{id}")
    public ${entity} getById(@PathVariable Long id) {
        return ${entity.toLowerCase()}Service.getById(id);
    }

    // 查询全部（Read All）
    @GetMapping("/getAll")
    public List<${entity}> getAll() {
        return ${entity.toLowerCase()}Service.list();
    }

    // 更新（Update）
    @PutMapping("/update")
    public String update(@RequestBody ${entity} ${entity.toLowerCase()}) {
            ${entity.toLowerCase()}Service.updateById(${entity.toLowerCase()});
        return "Updated successfully";
    }

    // 删除（Delete）
    @DeleteMapping("/delete/{id}")
    public String delete(@PathVariable Long id) {
            ${entity.toLowerCase()}Service.removeById(id);
        return "Deleted successfully";
    }

    // 分页查询（Pagination）
    @GetMapping("/page")
    public Page<${entity}> list(@RequestParam(defaultValue = "1") int current, @RequestParam(defaultValue = "10") int size) {
        return ${entity.toLowerCase()}Service.page(new Page<>(current, size));
    }
}

逻辑删除

  1. 修改实体类

    @Getter
@Setter
@TableName("sysuser")
public class SysUser implements Serializable {

    private static final long serialVersionUID = 1L;

    @TableId(value = "id", type = IdType.AUTO)
    private Integer id;

    private String username;

    private String password;

    //@TableLogic(value="0",delval="1")
    @TableLogic
    private Integer status;
}

设置mybatis延迟加载

# 设置延迟加载
mybatis.configuration.lazy-loading-enabled=true
# 取消积极加载
mybatis.configuration.aggressive-lazy-loading=false

取消下划线到驼峰的命名转换

mybatis-plus.configuration.map-underscore-to-camel-case=false