SpringBoot 2.1.7 集成 Mybatis

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本文链接： https://blog.csdn.net/weixx3/article/details/98838647

SpringBoot 2.1.7 集成 Mybatis

使用SpringBoot集成 Mybatis有两种方式，本文使用IDEA搭建：

• 1.Spring Initializr
• 2.使用IDEA插件

环境信息：
OS：Win10
Jdk：JavaSE 8
Ide：Idea Ultimate
MySQL：8.0.16
MyBatis：3.5.2
Spring Boot：2.1.7.RELEASE

2.创建Web项目

Idea集成了Spring Initializr，新建项目：

• 1.选择Spring Initializr，新建项目并填写基本信息
  

• 3.选择需要的工具
  选择Web、MySQL Driver和MyBatis Framework等必要依赖：

• 4.确认完成，build.gradle如下：

plugins {
	id 'org.springframework.boot' version '2.1.7.RELEASE'
	id 'java'
}

apply plugin: 'io.spring.dependency-management'

group = 'com.wxx'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = '1.8'

configurations {
	developmentOnly
	runtimeClasspath {
		extendsFrom developmentOnly
	}
	compileOnly {
		extendsFrom annotationProcessor
	}
}

repositories {
	mavenCentral()
}

dependencies {
	implementation 'org.springframework.boot:spring-boot-starter-web'
	implementation 'org.mybatis.spring.boot:mybatis-spring-boot-starter:2.1.0'
	compileOnly 'org.projectlombok:lombok'
	developmentOnly 'org.springframework.boot:spring-boot-devtools'
	runtimeOnly 'mysql:mysql-connector-java'
	annotationProcessor 'org.springframework.boot:spring-boot-configuration-processor'
	annotationProcessor 'org.projectlombok:lombok'
	testImplementation 'org.springframework.boot:spring-boot-starter-test'
}

4.集成Mybatis

4.1 创建Domain

实体类有：Student、Score，与数据库表相对应；
Student:

@Data
@AllArgsConstructor
@NoArgsConstructor
@Builder
public class Student {
    private Integer id;
    private String name;
    private Integer age;
    private String sex;
    private String hobbies;
    private String address;
}

Score:

@Data
@Builder
@AllArgsConstructor
@NoArgsConstructor
public class Score {
    private Integer id;
    private Integer studentId;
    private String studentName;
    private String subject;
    private Integer subjectScore;
}

StudentScore、StudentScores，是关联查询时使用的，并没有相对应的表；

StudentScore:

@Data
@AllArgsConstructor
@NoArgsConstructor
@Builder
public class StudentScore {
    private String name;
    private Integer age;
    private String sex;
    private Score score;
}

StudentScores:

@Data
@AllArgsConstructor
@NoArgsConstructor
@Builder
public class StudentScores {
    private String name;
    private Integer age;
    private String sex;
    private List<Score> scoreList;
}

注：@Data，@Builder，@AllArgsConstructor，@NoArgsConstructor为lombok的注解

4.2 配置文件

application.properties：

spring.application.name=student-service
spring.boot.admin.client.enabled=true
spring.profiles.active=dev

配置日志、MySQL连接、MyBatis扫描包路径等信息；
application-dev.yml：

server:
  connection-timeout: 30000ms
  port: 8081
  servlet.context-path: /

logging:
  path: ./
  file: st.log
  #max-size: 10M
  #max-history: 1
  level:
    root: INFO
    org:
      springframework:
        web: INFO
    com:
      wxx:
        sbmm:
          mapper: DEBUG

spring:
  data:
    mongodb:
      database: studentService
      host: localhost
      port: 27017
  datasource:
    # 遇到时区问题用这个
    # jdbc:mysql://localhost:3306?useUnicode=true&characterEncoding=UTF-8&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=UTC
    url: jdbc:mysql://localhost:3306/studentService?useSSL=false&useUnicode=true&characterEncoding=UTF-8&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=UTC
    driver-class-name: com.mysql.cj.jdbc.Driver
    username: root
    password: 12345678
    # schema.sql中一般存放的是DDL脚本，即通常为创建或更新库表的脚本
    # data.sql中一般是DML脚本，即通常为数据插入脚本
    schema: classpath:schema.sql
    data: classpath:data.sql
    platform: mysql
    initialization-mode: always
    continue-on-error: false
    #data-password:
    #data-username:
    #schema-password:
    #schema-username:
    sql-script-encoding: utf-8
    separator: ;
    # type: com.alibaba.druid.pool.DruidDataSource

mybatis:
  mapper-locations: classpath:mapper/*.xml
  type-aliases-package: com.wxx.sbmm.domain
  # config-location:
  configuration:
    cache-enabled: true

MyBatis配置信息，参考[Configuration部分]：http://www.mybatis.org/spring-boot-starter/mybatis-spring-boot-autoconfigure/index.html

这里使用springboot默认的数据库连接池；
配置中使用schema.sql存放创建库表的脚本，data.sql数据插入脚本，这是springboot的默认配置；

更多SpringBoot配置信息，参考：https://docs.spring.io/spring-boot/docs/current/reference/html/common-application-properties.html

4.3 配置数据库初始化脚本

数据库为：studentService
手动创建数据库：CREATE SCHEMA `studentService` DEFAULT CHARACTER SET utf8 ;
包含两个表，针对它们进行单表查询和关联查询：
学生表：t_student
成绩表：t_score
ER图：

schema.sql：初始化库表SQL

CREATE DATABASE IF NOT EXISTS `studentService`;

CREATE TABLE IF NOT EXISTS `t_student` (
`id` INT NOT NULL AUTO_INCREMENT COMMENT 'ID',
`name` VARCHAR(255)  DEFAULT "" COMMENT '姓名',
`age` INT DEFAULT 10 COMMENT '年龄',
`sex` VARCHAR(255)DEFAULT "Male" COMMENT '性别',
`hobbies` VARCHAR(255) DEFAULT "" COMMENT '爱好',
`address` VARCHAR(255) DEFAULT "" COMMENT '住址',
PRIMARY KEY(`id`),
UNIQUE INDEX  `idx_student_name_address` (`name`,`address`) USING BTREE
)ENGINE = INNODB DEFAULT CHARSET=utf8 AUTO_INCREMENT = 1  COMMENT '学生表';

CREATE TABLE IF NOT EXISTS `t_score` (
  `id` INT NOT NULL AUTO_INCREMENT COMMENT 'ID',
`student_id` INT DEFAULT 0 COMMENT '学生ID',
`student_name` VARCHAR(255) DEFAULT "" COMMENT '学生姓名',
`subject` VARCHAR(255) DEFAULT "" COMMENT '学科',
`subject_score` INT COMMENT '学科成绩',
PRIMARY KEY(`id`),
UNIQUE INDEX  `idx_score_studentname_subject` (`student_name`,`subject`) USING BTREE ,
FOREIGN KEY (student_id) REFERENCES t_student (id)
)ENGINE = INNODB DEFAULT CHARSET=utf8 AUTO_INCREMENT = 1  COMMENT '学生成绩表';

data.sql：初始化数据SQL

INSERT INTO t_student (name,age, sex, hobbies,  address)
  SELECT "Even",9,"Male","ShuXue,English","XiAn" FROM DUAL WHERE NOT EXISTS(SELECT 1 FROM t_student WHERE name = "Even");
INSERT INTO t_student (name,age, sex, hobbies,  address)
  SELECT "Weison",11,"Male","XuWen,WuLi","HeNan" FROM DUAL WHERE NOT EXISTS(SELECT 1 FROM t_student WHERE name = "Weison");
INSERT INTO t_student (name,age, sex, hobbies,  address)
  SELECT "Angule",13,"Female","XuWen,English","Chengdu" FROM DUAL WHERE NOT EXISTS(SELECT 1 FROM t_student WHERE name = "Angule");


INSERT INTO t_score (student_id,student_name, subject,  subject_score)
  SELECT 1,"Even","YuWen",90 FROM DUAL WHERE NOT EXISTS(SELECT 1 FROM t_score WHERE student_name = "Even" and subject ="YuWen");

INSERT INTO t_score (student_id,student_name, subject,  subject_score)
  SELECT 1,"Even","ShuXue",89 FROM DUAL WHERE NOT EXISTS(SELECT 1 FROM t_score WHERE student_name = "Even" and subject ="ShuXue");

INSERT INTO t_score (student_id,student_name, subject,  subject_score)
  SELECT 1,"Even","English",67 FROM DUAL WHERE NOT EXISTS(SELECT 1 FROM t_score WHERE student_name = "Even" and subject ="English");

INSERT INTO t_score (student_id,student_name, subject,  subject_score)
  SELECT 2,"Weison","YuWen",69 FROM DUAL WHERE NOT EXISTS(SELECT 1 FROM t_score WHERE student_name = "Weison" and subject ="YuWen");
INSERT INTO t_score (student_id,student_name, subject,  subject_score)
  SELECT 2,"Weison","ShuXue",94 FROM DUAL WHERE NOT EXISTS(SELECT 1 FROM t_score WHERE student_name = "Weison" and subject ="ShuXue");
INSERT INTO t_score (student_id,student_name, subject,  subject_score)
  SELECT 2,"Weison","English",82 FROM DUAL WHERE NOT EXISTS(SELECT 1 FROM t_score WHERE student_name = "Weison" and subject ="English");


INSERT INTO t_score (student_id,student_name, subject,  subject_score)
  SELECT 3,"Angule","YuWen",58 FROM DUAL WHERE NOT EXISTS(SELECT 1 FROM t_score WHERE student_name = "Angule" and subject ="YuWen");
INSERT INTO t_score (student_id,student_name, subject,  subject_score)
  SELECT 3,"Angule","ShuXue",73 FROM DUAL WHERE NOT EXISTS(SELECT 1 FROM t_score WHERE student_name = "Angule" and subject ="ShuXue");
INSERT INTO t_score (student_id,student_name, subject,  subject_score)
  SELECT 3,"Angule","English",91 FROM DUAL WHERE NOT EXISTS(SELECT 1 FROM t_score WHERE student_name = "Angule" and subject ="English");

commit;

4.4 配置SQL XML

写sql的地方：StudentMapper.xml；

XML中sql标签id与Mapper接口中的方法名要一致，MyBatis会对他们进行关联去实现Mapper接口；

<?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.wxx.sbmm.mapper.StudentMapper">

    <!--
    执行增加操作的SQL语句
    1.id和parameterType 分别与StudentMapper接口中的addStudent方法的名字和 参数类型一致
    2.以#{studentName}的形式引用Student参数 的studentName属性，MyBatis将使用反射读取Student参数的此属性
    3.#{studentName}中studentName大小写敏感。引用其他的属性与此一致
    4.seGeneratedKeys设置为"true"表明要MyBatis获取由数据库自动生成的主键
    5.keyProperty="id"指定把获取到的主键值注入到Student的id属性
    -->


    <!-- 当表中字段名跟实体类字段名不一致 或 为了返回list类型 可以定义returnMap -->
    <resultMap id="studentMap" type="Student">
        <id column="id" property="id"/>
        <result column="name" property="name"/>
        <result column="age" property="age"/>
        <result column="sex" property="sex"/>
        <result column="hobbies" property="hobbies"/>
        <result column="address" property="address"/>
    </resultMap>

    <resultMap id="scoreResultMap" type="Score">
        <id column="id" property="id"/>
        <result column="student_id" property="studentId"/>
        <result column="student_name" property="studentName"/>
        <result column="subject" property="subject"/>
        <result column="subject_score" property="subjectScore"/>
    </resultMap>


    <!--增删改查 开始-->
    <!--新增 1-->
    <insert id="saveStudent" parameterType="Student" useGeneratedKeys="true" keyProperty="id">
        insert into t_student(name,age,sex,hobbies,address)
        values(#{name},#{age},#{sex},#{hobbies},#{address})
    </insert>

    <!--删除 1-->
    <delete id="deleteStudentByName" parameterType="String">
        delete from t_student where name=#{name}
    </delete>
    <!--删除 2-->
    <delete id="deleteByStudent" parameterType="Student">
        delete from t_student
        <where>
            1=1
            <if test="name != null and name != ''">
                and name = #{name}
            </if>
            <if test="age != null and age != ''">
                and age = #{age}
            </if>
            <if test="sex != null and sex != ''">
                and sex=#{sex}
            </if>
            <if test="hobbies != null and hobbies != ''">
                and hobbies=#{hobbies}
            </if>
            <if test="address != null and address != ''">
                and address=#{address}
            </if>
        </where>
    </delete>

    <!--修改 1-->
    <update id="updateStudent" parameterType="Student">
        update t_student set
        <if test="age != null and age != ''">
            age = #{age},
        </if>
        <if test="sex != null and sex != ''">
            sex = #{sex},
        </if>
        <if test="hobbies != null and hobbies != ''">
            hobbies = #{hobbies},
        </if>
        <if test="address != null and address != ''">
            address = #{address}
        </if>
        where name=#{name}
    </update>

    <!--查询 1  -->
    <select id="findStudentByName" parameterType="String" resultMap="studentMap">
        SELECT * FROM t_student where name = #{name};
    </select>

    <!--查询 2 返回list的select语句，注意resultMap的值是指向前面定义好的 -->
    <select id="findStudents" resultMap="studentMap">
        select * from t_student
    </select>

    <!--查询 2 返回list的select语句，注意resultMap的值是指向前面定义好的 -->
    <select id="findScores" resultMap="scoreResultMap">
        select * from t_score
    </select>

    <!--查询 3 利用 hashMap 传递多个参数 -->
    <select id="findStudentByMap" parameterType="Map" resultType="Student">
        select * from t_student
        <where>
            1=1
            <if test="name != null and name != ''">
                and name = #{name}
            </if>
            <if test="age != null and age != ''">
                and age = #{age}
            </if>
            <if test="sex != null and sex != ''">
                and sex=#{sex}
            </if>
            <if test="hobbies != null and hobbies != ''">
                and hobbies=#{hobbies}
            </if>
            <if test="address != null and address != ''">
                and address=#{address}
            </if>
        </where>
    </select>

    <!--查询 4 利用 hashMap 传递多个参数 -->
    <select id="findStudentByStudent" parameterType="Student" resultType="Student">
        select * from t_student
        <where>
            1=1
            <if test="name != null and name != ''">
                and name = #{name}
            </if>
            <if test="age != null and age != ''">
                and age = #{age}
            </if>
            <if test="sex != null and sex != ''">
                and sex=#{sex}
            </if>
            <if test="hobbies != null and hobbies != ''">
                and hobbies=#{hobbies}
            </if>
            <if test="address != null and address != ''">
                and address=#{address}
            </if>
        </where>
    </select>

    <!--查询 5 Mybatis 自带的多个参数传递方法 这个时候没有 parameterType, 但用到了类似 #{param1} 类似的参数 -->
    <select id="findStudentByAgeAndSex" resultType="com.wxx.sbmm.domain.Student">
        select * from t_student where age = #{param1} and sex=#{param2}
    </select>


    <!--增删改查 结束-->

    <!--联合查询 开始-->


    <!--联合查询:studentScoreListResultMap-->
    <resultMap id="studentScoreListResultMap" type="com.wxx.sbmm.domain.StudentScores">
        <id column="aid" jdbcType="INTEGER" property="id"/>
        <result column="name" jdbcType="VARCHAR" javaType="String" property="name"/>
        <result column="age" javaType="Integer" property="age"/>
        <result column="sex" javaType="String" property="sex"/>
        <collection property="scoreList" javaType="List" ofType="Score">
            <id column="bid" jdbcType="INTEGER" property="id"/>
            <result property="studentId" column="student_id"/>
            <result property="studentName" column="student_name"/>
            <result property="subject" column="subject"/>
            <result property="subjectScore" column="subject_score"/>
        </collection>
    </resultMap>

    <!--联合查询:studentScoreResultMap-->
    <resultMap id="studentScoreResultMap" type="com.wxx.sbmm.domain.StudentScore">
        <id column="aid" jdbcType="BIGINT" javaType="Integer" property="id"/>
        <result property="name" jdbcType="VARCHAR" javaType="String" column="name"/>
        <result property="age" column="age" jdbcType="VARCHAR" javaType="Integer"/>
        <result property="sex" column="sex" jdbcType="VARCHAR" javaType="String"/>
        <association property="score" javaType="com.wxx.sbmm.domain.Score">
            <id property="id" column="bid"/>
            <result property="studentId" column="student_id"/>
            <result property="studentName" column="student_name"/>
            <result property="subject" column="subject"/>
            <result property="subjectScore" column="subject_score"/>
        </association>
    </resultMap>

    <!-- 联合查询 1 findStudentScoreList-->
    <select id="findStudentScores" parameterType="Integer" resultMap="studentScoreListResultMap">
        select
        a.id aid,
        a.name name,
        a.age age,
        a.sex sex,
        b.id bid,
        b.student_id student_id,
        b.student_name student_name,
        b.subject subject,
        b.subject_score subject_score
        from t_student a
        left join t_score b
        on a.id=b.student_id
    </select>
    <!-- 联合查询 2 findStudentScore-->
    <select id="findStudentScore" resultMap="studentScoreResultMap">
        select
        a.id aid,
        a.name name,
        a.age age,
        a.sex sex,
        b.id bid,
        b.student_id student_id,
        b.student_name student_name,
        b.subject subject,
        b.subject_score subject_score
        from t_student a
        left join t_score b
        on a.id=b.student_id
        where b.subject = 'English'
        and a.name = b.student_name
    </select>
    <!-- 联合查询 结束 -->

</mapper>

Mapper XML 官方说明：http://www.mybatis.org/mybatis-3/sqlmap-xml.html#

5.代码

5.1 创建StudentMapper

使用@Mapper 注解标明 Mapper接口，MyBatis会帮我们去实现这个接口，该接口中方法与4.4xml中sql标签ID相对应：

package com.wxx.sbmm.mapper;


import com.wxx.sbmm.domain.Score;
import com.wxx.sbmm.domain.Student;
import com.wxx.sbmm.domain.StudentScore;
import com.wxx.sbmm.domain.StudentScores;
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Param;

import java.util.List;
import java.util.Map;

@Mapper
public interface StudentMapper {

    // 增删改查
    Integer saveStudent(Student student);

    Integer deleteStudentByName(@Param("name") String name);

    Integer deleteByStudent(Student student);

    Integer updateStudent(Student student);

    // 5种查询
    Student findStudentByName(@Param("name") String name);

    List<Student> findStudents();

    List<Student> findStudentByMap(Map<String, String> map);

    List<Student> findStudentByStudent(Student student);

    List<Student> findStudentByAgeAndSex(Integer age, String sex);

    // 关联查询
    List<StudentScores> findStudentScores();
    List<StudentScore> findStudentScore();

}

Mapper更多信息，参考：http://www.mybatis.org/spring/mappers.html#

5.2 创建Service

package com.wxx.sbmm.service;

import com.wxx.sbmm.domain.Student;
import com.wxx.sbmm.domain.StudentScore;
import com.wxx.sbmm.domain.StudentScores;
import com.wxx.sbmm.mapper.StudentMapper;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.util.List;
import java.util.Map;

@Service
public class StudentService {

    @Resource
    private StudentMapper studentMapper;


    public Integer addStudent(Student student) {
        return studentMapper.saveStudent(student);
    }

    public Integer deleteStudentByName(String name) {
        return studentMapper.deleteStudentByName(name);
    }

    public Integer deleteByStudent(Student student) {
        return studentMapper.deleteByStudent(student);
    }

    public Integer updateStudent(Student student) {
        return studentMapper.updateStudent(student);
    }


    public Student findStudentByName(String name) {
        return studentMapper.findStudentByName(name);
    }

    public List<Student> findStudents() {
        return studentMapper.findStudents();
    }

    public List<Student> findStudentByMap(Map<String, String> map) {
        return studentMapper.findStudentByMap(map);
    }

    public List<Student> findStudentByStudent(Student student) {
        return studentMapper.findStudentByStudent(student);
    }


    public List<Student> findStudentByAgeAndSex(Integer age, String sex) {
        return studentMapper.findStudentByAgeAndSex(age, sex);
    }

    public List<StudentScores> findStudentScores() {
        return studentMapper.findStudentScores();
    }

    public List<StudentScore> findStudentScore() {
        return studentMapper.findStudentScore();
    }

}

5.3 创建Controller

package com.wxx.sbmm.controller;

import com.wxx.sbmm.domain.Student;
import com.wxx.sbmm.domain.StudentScore;
import com.wxx.sbmm.domain.StudentScores;
import com.wxx.sbmm.service.StudentService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;

import java.util.HashMap;
import java.util.List;
import java.util.Map;

@RestController
public class StudentController {
    @Autowired
    private StudentService studentService;

    @PostMapping("/students")
    public Integer saveStudent(@RequestBody Student student) {
        Integer addNum = studentService.addStudent(student);
        return addNum;
    }

    @DeleteMapping("/students/{name}")
    public Integer deleteStudentByName(@PathVariable String name) {
        Integer deleteNum = studentService.deleteStudentByName(name);
        return deleteNum;
    }

    @DeleteMapping("/students")
    public Integer deleteStudentByStudent(@RequestBody Student student) {
        Integer deleteNum = studentService.deleteByStudent(student);
        return deleteNum;
    }

    @PutMapping("/students")
    public Integer updateStudent(@RequestBody Student student) {
        Integer updateNum = studentService.updateStudent(student);
        return updateNum;
    }

    @GetMapping("/students/{name}")
    public Student findStudentByName(@PathVariable String name) {
        Student student = studentService.findStudentByName(name);
        return student;
    }

    @GetMapping("/students")
    public List<Student> getStudentListByAgeAndSexAndHobbies() {
        List<Student> studentList = studentService.findStudents();
        return studentList;
    }

    @GetMapping("/students/map")
    public List<Student> findStudentByMap() {
        Map<String, String> map = new HashMap<>();
        map.put("name", "Even");
        List<Student> studentList = studentService.findStudentByMap(map);
        return studentList;
    }

    @GetMapping("/students/st")
    public List<Student> findStudentByStudent() {
        List<Student> studentList = studentService.findStudentByStudent(Student.builder().name("Even").build());
        return studentList;
    }

    @GetMapping("/students/{age}/{sex}")
    public List<Student> findStudentByAgeAndSex(@PathVariable Integer age, @PathVariable String sex) {
        List<Student> studentList = studentService.findStudentByAgeAndSex(age, sex);
        return studentList;
    }

    @GetMapping("/students/scores")
    public List<StudentScores> findStudentScores() {
        List<StudentScores> studentList = studentService.findStudentScores();
        return studentList;
    }

    @GetMapping("/students/score")
    public List<StudentScore> findStudentScore() {
        List<StudentScore> studentScores = studentService.findStudentScore();
        return studentScores;
    }

}

5.4 最终项目

应该是这个样子：
启动项目后，刷新数据库，看到数据库、表和数据都有了：

6. 测试

两个比较复杂的接口返回：
/students/scores：

/students/score：

代码 --> https://github.com/WeisonWei/springboot-aggregation/tree/master/springboot-mvc-mybatis