Mybatis-Plus的BaseMapper的用法

1、如何使用BaseMapper进行数据库的操作。

2、使用BaseMapper进行插入实体时如何让UUID的主键自动生成。

Student实体类，其中id属性主键为UUID

package com.huixiaoer.ant.api.model.bean;

import com.baomidou.mybatisplus.annotation.IdType;
import com.baomidou.mybatisplus.annotation.TableId;

public class Student {
    /**
     *
     * This field was generated by MyBatis Generator.
     * This field corresponds to the database column student.id
     *
     * @mbg.generated Thu Oct 31 14:09:39 CST 2019
     */
    @TableId(type= IdType.UUID)
    private String id;

    /**
     *
     * This field was generated by MyBatis Generator.
     * This field corresponds to the database column student.user_name
     *
     * @mbg.generated Thu Oct 31 14:09:39 CST 2019
     */
    private String userName;

    /**
     *
     * This field was generated by MyBatis Generator.
     * This field corresponds to the database column student.age
     *
     * @mbg.generated Thu Oct 31 14:09:39 CST 2019
     */
    private Integer age;

    /**
     *
     * This field was generated by MyBatis Generator.
     * This field corresponds to the database column student.phone
     *
     * @mbg.generated Thu Oct 31 14:09:39 CST 2019
     */
    private String phone;

    /**
     * This method was generated by MyBatis Generator.
     * This method corresponds to the database table student
     *
     * @mbg.generated Thu Oct 31 14:09:39 CST 2019
     */
    public Student(String id, String userName, Integer age, String phone) {
        this.id = id;
        this.userName = userName;
        this.age = age;
        this.phone = phone;
    }

    /**
     * This method was generated by MyBatis Generator.
     * This method corresponds to the database table student
     *
     * @mbg.generated Thu Oct 31 14:09:39 CST 2019
     */
    public Student() {
        super();
    }

    /**
     * This method was generated by MyBatis Generator.
     * This method returns the value of the database column student.id
     *
     * @return the value of student.id
     *
     * @mbg.generated Thu Oct 31 14:09:39 CST 2019
     */
    public String getId() {
        return id;
    }

    /**
     * This method was generated by MyBatis Generator.
     * This method sets the value of the database column student.id
     *
     * @param id the value for student.id
     *
     * @mbg.generated Thu Oct 31 14:09:39 CST 2019
     */
    public void setId(String id) {
        this.id = id == null ? null : id.trim();
    }

    /**
     * This method was generated by MyBatis Generator.
     * This method returns the value of the database column student.user_name
     *
     * @return the value of student.user_name
     *
     * @mbg.generated Thu Oct 31 14:09:39 CST 2019
     */
    public String getUserName() {
        return userName;
    }

    /**
     * This method was generated by MyBatis Generator.
     * This method sets the value of the database column student.user_name
     *
     * @param userName the value for student.user_name
     *
     * @mbg.generated Thu Oct 31 14:09:39 CST 2019
     */
    public void setUserName(String userName) {
        this.userName = userName == null ? null : userName.trim();
    }

    /**
     * This method was generated by MyBatis Generator.
     * This method returns the value of the database column student.age
     *
     * @return the value of student.age
     *
     * @mbg.generated Thu Oct 31 14:09:39 CST 2019
     */
    public Integer getAge() {
        return age;
    }

    /**
     * This method was generated by MyBatis Generator.
     * This method sets the value of the database column student.age
     *
     * @param age the value for student.age
     *
     * @mbg.generated Thu Oct 31 14:09:39 CST 2019
     */
    public void setAge(Integer age) {
        this.age = age;
    }

    /**
     * This method was generated by MyBatis Generator.
     * This method returns the value of the database column student.phone
     *
     * @return the value of student.phone
     *
     * @mbg.generated Thu Oct 31 14:09:39 CST 2019
     */
    public String getPhone() {
        return phone;
    }

    /**
     * This method was generated by MyBatis Generator.
     * This method sets the value of the database column student.phone
     *
     * @param phone the value for student.phone
     *
     * @mbg.generated Thu Oct 31 14:09:39 CST 2019
     */
    public void setPhone(String phone) {
        this.phone = phone == null ? null : phone.trim();
    }
}

StudnetVI实体类，用户从页面接收参数

package com.huixiaoer.ant.api.model.vi;

import io.swagger.annotations.ApiModel;
import io.swagger.annotations.ApiModelProperty;

@ApiModel(value = "student对象",description = "学生对象student")
public class StudentVI {

    /**
     *
     * This field was generated by MyBatis Generator.
     * This field corresponds to the database column student.user_name
     *
     * @mbg.generated Thu Oct 31 14:09:39 CST 2019
     */
    @ApiModelProperty(value="学生姓名",name="userName",required=true)
    private String userName;

    /**
     *
     * This field was generated by MyBatis Generator.
     * This field corresponds to the database column student.age
     *
     * @mbg.generated Thu Oct 31 14:09:39 CST 2019
     */
    @ApiModelProperty(value="年龄",name="age",required=true)
    private Integer age;

    /**
     *
     * This field was generated by MyBatis Generator.
     * This field corresponds to the database column student.phone
     *
     * @mbg.generated Thu Oct 31 14:09:39 CST 2019
     */
    @ApiModelProperty(value="手机号",name="phone",required=true)
    private String phone;

    public String getUserName() {
        return userName;
    }

    public void setUserName(String userName) {
        this.userName = userName;
    }

    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }

    public String getPhone() {
        return phone;
    }

    public void setPhone(String phone) {
        this.phone = phone;
    }

}

StudentPlusMapper接口类，实现BaseMapper用来实现Mybatis-Plus的增强功能。

package com.huixiaoer.ant.api.repository.mysql.mapper;

import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.huixiaoer.ant.api.model.bean.Student;

public interface StudentPlusMapper extends BaseMapper<Student> {
    //不需要实现，这时候就可以调用baseMapper的增删改查了
}

StudentService业务接口类

package com.huixiaoer.ant.api.service;

import com.huixiaoer.ant.api.model.bean.Student;
import com.huixiaoer.ant.api.model.bean.StudentExample;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Param;
import org.apache.ibatis.annotations.SelectKey;

import java.util.List;

public interface StudentService {
    /**
     * This method was generated by MyBatis Generator.
     * This method corresponds to the database table student
     *
     * @mbg.generated Thu Oct 31 14:09:39 CST 2019
     */
    long countByExample(StudentExample example);

    /**
     * This method was generated by MyBatis Generator.
     * This method corresponds to the database table student
     *
     * @mbg.generated Thu Oct 31 14:09:39 CST 2019
     */
    int deleteByExample(StudentExample example);

    /**
     * This method was generated by MyBatis Generator.
     * This method corresponds to the database table student
     *
     * @mbg.generated Thu Oct 31 14:09:39 CST 2019
     */
    @Insert({
        "insert into student (id, user_name, ",
        "age, phone)",
        "values (#{id,jdbcType=VARCHAR}, #{userName,jdbcType=VARCHAR}, ",
        "#{age,jdbcType=INTEGER}, #{phone,jdbcType=VARCHAR})"
    })
    @SelectKey(statement="select uuid_short()", keyProperty="id", before=true, resultType=String.class)
    int insert(Student record);

    /**
     * This method was generated by MyBatis Generator.
     * This method corresponds to the database table student
     *
     * @mbg.generated Thu Oct 31 14:09:39 CST 2019
     */
    int insertSelective(Student record);

    /**
     * This method was generated by MyBatis Generator.
     * This method corresponds to the database table student
     *
     * @mbg.generated Thu Oct 31 14:09:39 CST 2019
     */
    List<Student> selectByExample(StudentExample example);

    /**
     * This method was generated by MyBatis Generator.
     * This method corresponds to the database table student
     *
     * @mbg.generated Thu Oct 31 14:09:39 CST 2019
     */
    int updateByExampleSelective(@Param("record") Student record, @Param("example") StudentExample example);

    /**
     * This method was generated by MyBatis Generator.
     * This method corresponds to the database table student
     *
     * @mbg.generated Thu Oct 31 14:09:39 CST 2019
     */
    int updateByExample(@Param("record") Student record, @Param("example") StudentExample example);
}

StudentServiceImpl业务接口实现类，这里将mybatis-plus的mapper接口注入其中。

package com.huixiaoer.ant.api.service.impl;

import com.huixiaoer.ant.api.model.bean.Student;
import com.huixiaoer.ant.api.model.bean.StudentExample;
import com.huixiaoer.ant.api.repository.mysql.mapper.StudentMapper;
import com.huixiaoer.ant.api.repository.mysql.mapper.StudentPlusMapper;
import com.huixiaoer.ant.api.service.StudentService;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

@Service
@Slf4j
public class StudentServiceImpl implements StudentService {

    @Autowired
    private StudentMapper studentMapper;

    @Autowired
    private StudentPlusMapper studentPlusMapper;

    @Override
    public long countByExample(StudentExample example) {
        return 0;
    }

    @Override
    public int deleteByExample(StudentExample example) {
        return 0;
    }

    @Override
    public int insert(Student record) {
        return studentPlusMapper.insert(record);
    }

    @Override
    public int insertSelective(Student record) {
        return studentMapper.insertSelective(record);
    }

    @Override
    public List<Student> selectByExample(StudentExample example) {
        return null;
    }

    @Override
    public int updateByExampleSelective(Student record, StudentExample example) {
        return 0;
    }

    @Override
    public int updateByExample(Student record, StudentExample example) {
        return 0;
    }
}

SchoolController类，实现前端和后台的交互。自动注入学生业务实现类。

package com.huixiaoer.ant.api.controller;

import com.huixiaoer.ant.api.common.constant.ResultCode;
import com.huixiaoer.ant.api.model.bean.Student;
import com.huixiaoer.ant.api.model.vi.StudentVI;
import com.huixiaoer.ant.api.service.impl.StudentServiceImpl;
import com.huixiaoer.ant.api.util.*;
import io.swagger.annotations.*;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.util.UUID;

/**
 * @author create by yiqiang.wu
 * @create 2019/06/12
 * @email yiqiang.wu@huixiaoer.com
 * @description 登录
 */
@Slf4j
@RestController
@Api(tags = "学校 相关接口")
public class SchoolController {

    @Autowired
    private StudentServiceImpl studentService;

    @Autowired
    private HttpServletRequest request;

    @ApiOperation(value = "增加学生信息")
    @PostMapping(value = "/insert/student")
    public CommonResult insertStudent(@RequestBody @ApiParam(name="学生对象",value="传入json格式",required=true) StudentVI studentVI) {
        try {
            Student student = new Student();
//            student.setId(UUID.randomUUID().toString());
            student.setUserName(studentVI.getUserName());
            student.setAge(studentVI.getAge());
            student.setPhone(studentVI.getPhone());
            studentService.insert(student);
        } catch (Exception e) {
            System.out.println(e);
            return CommonUtil.buildResponse(ResultCode.SYSTEM_ERROR, ResultCode.SYSTEM_ERROR_MSG);
        }
        return CommonUtil.buildResponse(ResultCode.SUCCESS, ResultCode.SUCCESS_MSG);
    }

}

补充一下Mybatis的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.huixiaoer.ant.api.repository.mysql.mapper.StudentMapper">
  <resultMap id="BaseResultMap" type="com.huixiaoer.ant.api.model.bean.Student">
    <!--
      WARNING - @mbg.generated
      This element is automatically generated by MyBatis Generator, do not modify.
      This element was generated on Thu Oct 31 14:09:39 CST 2019.
    -->
    <constructor>
      <arg column="id" javaType="java.lang.String" jdbcType="VARCHAR" />
      <arg column="user_name" javaType="java.lang.String" jdbcType="VARCHAR" />
      <arg column="age" javaType="java.lang.Integer" jdbcType="INTEGER" />
      <arg column="phone" javaType="java.lang.String" jdbcType="VARCHAR" />
    </constructor>
  </resultMap>
  <sql id="Example_Where_Clause">
    <!--
      WARNING - @mbg.generated
      This element is automatically generated by MyBatis Generator, do not modify.
      This element was generated on Thu Oct 31 14:09:39 CST 2019.
    -->
    <where>
      <foreach collection="oredCriteria" item="criteria" separator="or">
        <if test="criteria.valid">
          <trim prefix="(" prefixOverrides="and" suffix=")">
            <foreach collection="criteria.criteria" item="criterion">
              <choose>
                <when test="criterion.noValue">
                  and ${criterion.condition}
                </when>
                <when test="criterion.singleValue">
                  and ${criterion.condition} #{criterion.value}
                </when>
                <when test="criterion.betweenValue">
                  and ${criterion.condition} #{criterion.value} and #{criterion.secondValue}
                </when>
                <when test="criterion.listValue">
                  and ${criterion.condition}
                  <foreach close=")" collection="criterion.value" item="listItem" open="(" separator=",">
                    #{listItem}
                  </foreach>
                </when>
              </choose>
            </foreach>
          </trim>
        </if>
      </foreach>
    </where>
  </sql>
  <sql id="Update_By_Example_Where_Clause">
    <!--
      WARNING - @mbg.generated
      This element is automatically generated by MyBatis Generator, do not modify.
      This element was generated on Thu Oct 31 14:09:39 CST 2019.
    -->
    <where>
      <foreach collection="example.oredCriteria" item="criteria" separator="or">
        <if test="criteria.valid">
          <trim prefix="(" prefixOverrides="and" suffix=")">
            <foreach collection="criteria.criteria" item="criterion">
              <choose>
                <when test="criterion.noValue">
                  and ${criterion.condition}
                </when>
                <when test="criterion.singleValue">
                  and ${criterion.condition} #{criterion.value}
                </when>
                <when test="criterion.betweenValue">
                  and ${criterion.condition} #{criterion.value} and #{criterion.secondValue}
                </when>
                <when test="criterion.listValue">
                  and ${criterion.condition}
                  <foreach close=")" collection="criterion.value" item="listItem" open="(" separator=",">
                    #{listItem}
                  </foreach>
                </when>
              </choose>
            </foreach>
          </trim>
        </if>
      </foreach>
    </where>
  </sql>
  <sql id="Base_Column_List">
    <!--
      WARNING - @mbg.generated
      This element is automatically generated by MyBatis Generator, do not modify.
      This element was generated on Thu Oct 31 14:09:39 CST 2019.
    -->
    id, user_name, age, phone
  </sql>
  <select id="selectByExample" parameterType="com.huixiaoer.ant.api.model.bean.StudentExample" resultMap="BaseResultMap">
    <!--
      WARNING - @mbg.generated
      This element is automatically generated by MyBatis Generator, do not modify.
      This element was generated on Thu Oct 31 14:09:39 CST 2019.
    -->
    select
    <if test="distinct">
      distinct
    </if>
    <include refid="Base_Column_List" />
    from student
    <if test="_parameter != null">
      <include refid="Example_Where_Clause" />
    </if>
    <if test="orderByClause != null">
      order by ${orderByClause}
    </if>
  </select>
  <delete id="deleteByExample" parameterType="com.huixiaoer.ant.api.model.bean.StudentExample">
    <!--
      WARNING - @mbg.generated
      This element is automatically generated by MyBatis Generator, do not modify.
      This element was generated on Thu Oct 31 14:09:39 CST 2019.
    -->
    delete from student
    <if test="_parameter != null">
      <include refid="Example_Where_Clause" />
    </if>
  </delete>
  <insert id="insertSelective" parameterType="com.huixiaoer.ant.api.model.bean.Student">
    <!--
      WARNING - @mbg.generated
      This element is automatically generated by MyBatis Generator, do not modify.
      This element was generated on Thu Oct 31 14:09:39 CST 2019.
    -->
    <selectKey keyProperty="id" order="BEFORE" resultType="java.lang.String">
      select uuid_short()
    </selectKey>
    insert into student
    <trim prefix="(" suffix=")" suffixOverrides=",">
      id,
      <if test="userName != null">
        user_name,
      </if>
      <if test="age != null">
        age,
      </if>
      <if test="phone != null">
        phone,
      </if>
    </trim>
    <trim prefix="values (" suffix=")" suffixOverrides=",">
      #{id,jdbcType=VARCHAR},
      <if test="userName != null">
        #{userName,jdbcType=VARCHAR},
      </if>
      <if test="age != null">
        #{age,jdbcType=INTEGER},
      </if>
      <if test="phone != null">
        #{phone,jdbcType=VARCHAR},
      </if>
    </trim>
  </insert>
  <select id="countByExample" parameterType="com.huixiaoer.ant.api.model.bean.StudentExample" resultType="java.lang.Long">
    <!--
      WARNING - @mbg.generated
      This element is automatically generated by MyBatis Generator, do not modify.
      This element was generated on Thu Oct 31 14:09:39 CST 2019.
    -->
    select count(*) from student
    <if test="_parameter != null">
      <include refid="Example_Where_Clause" />
    </if>
  </select>
  <update id="updateByExampleSelective" parameterType="map">
    <!--
      WARNING - @mbg.generated
      This element is automatically generated by MyBatis Generator, do not modify.
      This element was generated on Thu Oct 31 14:09:39 CST 2019.
    -->
    update student
    <set>
      <if test="record.id != null">
        id = #{record.id,jdbcType=VARCHAR},
      </if>
      <if test="record.userName != null">
        user_name = #{record.userName,jdbcType=VARCHAR},
      </if>
      <if test="record.age != null">
        age = #{record.age,jdbcType=INTEGER},
      </if>
      <if test="record.phone != null">
        phone = #{record.phone,jdbcType=VARCHAR},
      </if>
    </set>
    <if test="_parameter != null">
      <include refid="Update_By_Example_Where_Clause" />
    </if>
  </update>
  <update id="updateByExample" parameterType="map">
    <!--
      WARNING - @mbg.generated
      This element is automatically generated by MyBatis Generator, do not modify.
      This element was generated on Thu Oct 31 14:09:39 CST 2019.
    -->
    update student
    set id = #{record.id,jdbcType=VARCHAR},
      user_name = #{record.userName,jdbcType=VARCHAR},
      age = #{record.age,jdbcType=INTEGER},
      phone = #{record.phone,jdbcType=VARCHAR}
    <if test="_parameter != null">
      <include refid="Update_By_Example_Where_Clause" />
    </if>
  </update>
</mapper>

各种UUID生成策略，生成的UUID值进行比较。