Mybatis-Plus BaseMapper的用法详解

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 {
  //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 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 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 [email protected]
 * @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

 
  
  
   
   
   
   
  
 
 
  
  
   
    
     
      
       
        
         and ${criterion.condition}
        
        
         and ${criterion.condition} #{criterion.value}
        
        
         and ${criterion.condition} #{criterion.value} and #{criterion.secondValue}
        
        
         and ${criterion.condition}
         
          #{listItem}
         
        
       
      
     
    
   
  
 
 
  
  
   
    
     
      
       
        
         and ${criterion.condition}
        
        
         and ${criterion.condition} #{criterion.value}
        
        
         and ${criterion.condition} #{criterion.value} and #{criterion.secondValue}
        
        
         and ${criterion.condition}
         
          #{listItem}
         
        
       
      
     
    
   
  
 
 
  
  id, user_name, age, phone
 
 
  
  select
  
   distinct
  
  
  from student
  
   
  
  
   order by ${orderByClause}
  
 
 
  
  delete from student
  
   
  
 
 
  
  
   select uuid_short()
  
  insert into student
  
   id,
   
    user_name,
   
   
    age,
   
   
    phone,
   
  
  
   #{id,jdbcType=VARCHAR},
   
    #{userName,jdbcType=VARCHAR},
   
   
    #{age,jdbcType=INTEGER},
   
   
    #{phone,jdbcType=VARCHAR},
   
  
 
 
  
  select count(*) from student
  
   
  
 
 
  
  update student
  
   
    id = #{record.id,jdbcType=VARCHAR},
   
   
    user_name = #{record.userName,jdbcType=VARCHAR},
   
   
    age = #{record.age,jdbcType=INTEGER},
   
   
    phone = #{record.phone,jdbcType=VARCHAR},
   
  
  
   
  
 
 
  
  update student
  set id = #{record.id,jdbcType=VARCHAR},
   user_name = #{record.userName,jdbcType=VARCHAR},
   age = #{record.age,jdbcType=INTEGER},
   phone = #{record.phone,jdbcType=VARCHAR}
  
   
  
 

各种UUID生成策略，生成的UUID值进行比较。

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