Spring Boot整合Mybatis

一、引入依賴

<!--引入mybatis-->
<dependency>
    <groupId>org.mybatis.spring.boot</groupId>
    <artifactId>mybatis-spring-boot-starter</artifactId>
    <version>2.1.2</version>
</dependency>
<!--引入mysql驅動-->
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <scope>runtime</scope>
</dependency>
<!-- alibaba的druid數據庫鏈接池 -->
<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>druid-spring-boot-starter</artifactId>
    <version>1.1.10</version>
</dependency>
<!--引入lombok-->
<dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
    <version>1.16.10</version>
</dependency>

能夠看到mybatis的starter中導入了spring-boot-starter-jdbc，所以這裏不須要再次導入jdbc依賴

二、配置application.yml文件

2.一、配置數據源

spring:
  # 配置數據源
  datasource:
    # 數據庫url
    url: jdbc:mysql://127.0.0.1:3306/test?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8&useSSL=true
    # 用戶名
    username: root
    # 密碼
    password: root
    # 驅動類
    driver-class-name: com.mysql.cj.jdbc.Driver
    # 配置數據源類型，這裏選擇druid
    type: com.alibaba.druid.pool.DruidDataSource
    # druid相關配置
    druid:
      #初始化大小
      initialSize: 5
      #最小值
      minIdle: 5
      #最大值
      maxActive: 20
      #最大等待時間，配置獲取鏈接等待超時，時間單位都是毫秒ms
      maxWait: 60000
      #配置間隔多久才進行一次檢測，檢測須要關閉的空閒鏈接
      timeBetweenEvictionRunsMillis: 60000
      #配置一個鏈接在池中最小生存的時間
      minEvictableIdleTimeMillis: 300000
      validationQuery: SELECT 1 FROM DUAL
      testWhileIdle: true
      testOnBorrow: false
      testOnReturn: false
      poolPreparedStatements: true
      # 配置監控統計攔截的filters，去掉後監控界面sql沒法統計，
      #'wall'用於防火牆，SpringBoot中沒有log4j，我改爲了log4j2
      filters: stat,wall,log4j2
      #最大PSCache鏈接
      maxPoolPreparedStatementPerConnectionSize: 20
      useGlobalDataSourceStat: true
      # 經過connectProperties屬性來打開mergeSql功能；慢SQL記錄
      connectionProperties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=500
      # 配置StatFilter
      web-stat-filter:
        #默認爲false，設置爲true啓動
        enabled: true
        url-pattern: "/*"
        exclusions: "*.js,*.gif,*.jpg,*.bmp,*.png,*.css,*.ico,/druid/*"
      #配置StatViewServlet
      stat-view-servlet:
        url-pattern: "/druid/*"
        #容許那些ip
        allow: 127.0.0.1
        login-username: admin
        login-password: 123456
        # 禁止那些ip
        deny: 192.168.1.102
        #是否能夠重置
        reset-enable: true
        #啓用
        enabled: true

2.二、創建JavaBean

package com.cheng.cache.pojo;

import lombok.Getter;
import lombok.Setter;

/**
 * @author cheng
 * @version 1.0
 * @date 2020/3/21
 */
@Getter
@Setter
public class Student
{
    private Integer id;

    private String name;

    private Integer age;
}

2.三、註解版Mybatis的使用

• 配置application.yml文件（能夠不用配置）

# 配置mybatis
mybatis:
  # pojo類所在路勁
  type-aliases-package: com.cheng.cache.pojo
  configuration:
    # 配置項：開啓下劃線到駝峯的自動轉換. 做用：將數據庫字段根據駝峯規則自動注入到對象屬性。
    map-underscore-to-camel-case: true

• 給啓動類添加註解，掃描Mapper

@MapperScan("com.cheng.cache.mapper")

• 編寫Mapper接口

public interface StudentMapper
{
    @Options(useGeneratedKeys = true, keyProperty = "id")
    @Insert("insert into student(name, age) values(#{name}, #{age})")
    public int insert(Student student);

    @Delete("delete from student where id = #{id}")
    public int delete(Integer id);

    @Select("select * from student where id = #{id}")
    public Student select(Integer id);

    @Update("update student set name = #{name},age = #{age} where id = #{id}")
    public int update(Student student);
}

配置版Mybatis的使用

• 配置yml文件

# 配置mybatis
mybatis:
  # 映射文件所在路徑
  mapper-locations: classpath:mybatis/mapper/*.xml
  # pojo類所在路徑
  type-aliases-package: com.cheng.cache.pojo
  configuration:
    #配置項：開啓下劃線到駝峯的自動轉換. 做用：將數據庫字段根據駝峯規則自動注入到對象屬性。
    map-underscore-to-camel-case: true

• 編寫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.cheng.cache.xmlmapper.XmlStudentMapper">

    <!--resultMap是Mybatis最強大的元素，它能夠將查詢到的複雜數據（好比查詢到幾個表中數據）映射到一個結果集當中-->
    <resultMap id="baseMap" type="com.cheng.cache.pojo.Student">
        <!--column不作限制，能夠爲任意表的字段，而property須爲type 定義的pojo屬性-->
        <id column="id" property="id" jdbcType="INTEGER"></id>
        <result column="name" property="name" jdbcType="VARCHAR"></result>
        <result column="age" property="age" jdbcType="INTEGER"></result>
    </resultMap>

    <!--public Student select(Integer id);-->
    <select id="select" parameterType="java.lang.Integer" resultMap="baseMap">
        select *
        from student
        where id = #{id}
    </select>

    <!--public int insert(Student student);-->
    <insert id="insert" parameterType="com.cheng.cache.pojo.Student" useGeneratedKeys="true" keyProperty="id">
        insert into student(name, age)
        values(#{name}, #{age})
    </insert>

    <!--public int delete(Integer id);-->
    <delete id="delete" parameterType="java.lang.Integer">
        delete from student
        where id = #{id}
    </delete>

    <!--public int update(Student student);-->
    <update id="update" parameterType="com.cheng.cache.pojo.Student">
        update student
        set name = #{name}, age=#{age}
        where id = #{id}
    </update>

</mapper>