前言：本篇文章完整详细介绍了SpringBoot整合MyBatis-Plus的完整过程，这边我的SpringBoot版本是2.4版本、JDK1.8和Maven3.8.1版本，跟着文章一步步走就可以了，MyBatis-Plus整合非常方便，也是现在企业开发中经常会用的一个持久层框架。
目录
一、导入依赖
二、yml配置文件
三、实现核心逻辑
3.1、新增实体类
3.2、新增持久层
3.3、实现服务层
四、实现增删查改
4.1、新增数据
4.2、修改数据
4.3、删除数据
4.4、基础查询
4.5、自定义查询
五、Gitee源码
一、导入依赖
在pom.xml文件中引入如下依赖：
<!-- MyBatis-Plus -->
<dependency>
<groupId>com.baomidou</groupId>
<artifactId>mybatis-plus-boot-starter</artifactId>
<version>3.5.1</version>
</dependency>
<!-- 数据库驱动 -->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.28</version>
</dependency>
<!-- Lombok (可选) -->
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<version>1.18.24</version>
<scope>provided</scope>
</dependency>二、yml配置文件
完整代码：
server:
port: 9090
spring:
datasource:
username: 用户名
password: 密码
url: jdbc:mysql://ip地址:3306/数据库?useUnicode=true&characterEncoding=utf-8&useSSL=false&serverTimezone=UTC
driver-class-name: com.mysql.cj.jdbc.Driver
mybatis-plus:
# 搜索指定包别名（改成自己的）
typeAliasesPackage: com.example.mybatisplus.domain
# 配置mapper的扫描，找到所有的mapper.xml映射文件
mapperLocations: classpath*:mapper/**/*Mapper.xml
configuration:
# 其他 MyBatis 配置
map-underscore-to-camel-case: true # 将数据库下划线转为驼峰命名
cache-enabled: false # 是否开启二级缓存
lazy-loading-enabled: true # 是否开启懒加载
log-impl: org.apache.ibatis.logging.stdout.StdOutImpl # 设置Mybatis的日志实现类为控制台输出
三、实现核心逻辑
实现Service、Mapper和Xml三个核心文件，先看一下项目整体结构：
3.1、新增实体类
package com.example.mybatisplus.domain;
import com.baomidou.mybatisplus.annotation.IdType;
import com.baomidou.mybatisplus.annotation.TableId;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import java.util.Date;
import com.fasterxml.jackson.annotation.JsonFormat;
@Data
@AllArgsConstructor
@NoArgsConstructor
public class Student {
/**
* 主键
*/
@TableId(type = IdType.AUTO)
private Integer id;
/**
* 姓名
*/
private String name;
/**
* 性别
*/
private String sex;
/**
* 电话
*/
private String phone;
/**
* 地址
*/
private String address;
/**
* 电子邮箱
*/
private String email;
/**
* 入学时间
*/
@JsonFormat(pattern = "yyyy-MM-dd")
private Date registerTime;
/**
* 毕业时间
*/
@JsonFormat(pattern = "yyyy-MM-dd")
private Date graduateTime;
/**
* 学号
*/
private String number;
/**
* 所属班级
*/
private String className;
/**
* 用户ID
*/
private Integer userId;
}
3.2、新增持久层
package com.example.mybatisplus.mapper;
import java.util.List;
import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.example.mybatisplus.domain.Student;
import org.apache.ibatis.annotations.Mapper;
import org.springframework.stereotype.Repository;
@Mapper
@Repository
public interface StudentMapper extends BaseMapper<Student>
{
/**
* 查询
* @param student
* @return
*/
public List<Student> selectStudentList(Student student);
}
3.3、实现服务层
package com.example.mybatisplus.service;
import javax.annotation.Resource;
import java.util.List;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.example.mybatisplus.domain.Student;
import com.example.mybatisplus.mapper.StudentMapper;
import org.springframework.stereotype.Service;
@Service
public class StudentService extends ServiceImpl<StudentMapper, Student> {
@Resource
private StudentMapper studentMapper;
public List<Student> selectStudentList(Student student) {
return studentMapper.selectStudentList(student);
}
}
4.4、XML文件
<?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.example.mybatisplus.mapper.StudentMapper">
<select id="selectStudentList" resultType="Student">
select * from student
<where>
<if test="id != null "> and id = #{id} </if>
<if test="name != null and name != ''"> and name like concat('%', #{name}, '%') </if>
<if test="sex != null and sex != ''"> and sex like concat('%', #{sex}, '%') </if>
<if test="phone != null and phone != ''"> and phone like concat('%', #{phone}, '%') </if>
<if test="address != null and address != ''"> and address like concat('%', #{address}, '%') </if>
<if test="email != null and email != ''"> and email like concat('%', #{email}, '%') </if>
<if test="registerTime != null "> and register_time = #{registerTime} </if>
<if test="graduateTime != null "> and graduate_time = #{graduateTime} </if>
<if test="number != null and number != ''"> and number like concat('%', #{number}, '%') </if>
<if test="className != null and className != ''"> and class_name like concat('%', #{className}, '%') </if>
<if test="userId != null "> and user_id = #{userId} </if>
</where>
</select>
</mapper>四、实现增删查改
以下是代码示例。
4.1、新增数据
@Resource
private StudentService studentService;
public void insert(){
Student student = new Student();
student.setName("张三");
student.setSex("1");
student.setPhone("18888888");
student.setEmail("199999@qq.com");
student.setRegisterTime(new Date());
student.setGraduateTime(new Date());
student.setNumber("187891124");
student.setClassName("高三1班");
student.setUserId(109);
studentService.save(student);
}4.2、修改数据
@Resource
private StudentService studentService;
public void update(){
//根据id获取
Student student = studentService.getById(2);
student.setName("李四");
student.setSex("0");
student.setPhone("15555555");
student.setEmail("16556224@qq.com");
studentService.updateById(student);
}4.3、删除数据
@Resource
private StudentService studentService;
public void delete(){
studentService.removeById(1);
}4.4、基础查询
@Resource
private StudentService studentService;
public void select() {
Student query = new Student();
query.setName("张三");
List<Student> studentList = studentService.selectStudentList(query);
for(Student student : studentList){
System.out.println(student);
}
}4.5、自定义查询
@Resource
private StudentMapper studentMapper;
public void query(){
List<Integer> ids = new ArrayList<>();
ids.add(9);
ids.add(10);
LambdaQueryWrapper<Student> lambdaQueryWrapper = new LambdaQueryWrapper<Student>();
//小于当前时间
lambdaQueryWrapper.lt(Student::getRegisterTime,new Date());
//包含的id
lambdaQueryWrapper.in(Student::getId,ids);
List<Student> list = studentMapper.selectList(lambdaQueryWrapper);
System.out.println(list);
}五、Gitee源码
源码地址：SpringBoot整合MyBatis-Plus完整详细版
