轻轻松松学习SpringBoot2：第二十一篇： Spring boot Mybatis 整合安装篇（完整版）

前面我们说了Spring Boot 数据库操作

1）JPA：

https://blog.csdn.net/stronglyh/article/details/80876666

https://blog.csdn.net/stronglyh/article/details/80904531

2）JDBC

https://blog.csdn.net/stronglyh/article/details/80934737

当然了，还有一种比较好的组合，那就是Spring Boot和MyBatis整合，为了保证引入的完整性，我们重新建一个工程

=========================第一部分：新建Mybatis工程============================

1）新建工程

2）选择Spring Initializr，其中jdk选择本地安装的

扫描二维码关注公众号，回复： 2046246 查看本文章

3）工程名

4）选择相关依赖，我们选择web和sql

点击finish完成

=========================第二部分：工程结构概览============================

我们习惯把application.properties改为application.yml，当然了，这个看个人喜好

我们看一下pom.xml文件内容

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.example</groupId>
    <artifactId>smybatis</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>smybatis</name>
    <description>Demo project for Spring Boot</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.3.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jdbc</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>1.3.2</version>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>5.1.46</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <!-- 分页插件 -->
        <dependency>
            <groupId>com.github.pagehelper</groupId>
            <artifactId>pagehelper-spring-boot-starter</artifactId>
            <version>1.2.5</version>
        </dependency>
        <!-- alibaba的druid数据库连接池 -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid-spring-boot-starter</artifactId>
            <version>1.1.9</version>
        </dependency>

    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
            <!-- mybatis generator 自动生成代码插件 -->
            <plugin>
                <groupId>org.mybatis.generator</groupId>
                <artifactId>mybatis-generator-maven-plugin</artifactId>
                <version>1.3.2</version>
                <configuration>
                    <configurationFile>${basedir}/src/main/resources/generator/generatorConfig.xml</configurationFile>
                    <overwrite>true</overwrite>
                    <verbose>true</verbose>
                </configuration>
            </plugin>

        </plugins>
    </build>

</project>

我们看到了mysql和mybatis相关依赖，其中我们使用了阿里的druid数据库连接池

最主要的是我们这次使用了代码自动生成插件mybatis generator，这样可以少些很多代码

我们再来初始化配置文件yml

server:
  port: 1234

spring:
    datasource:
        name: mysql_test
        type: com.alibaba.druid.pool.DruidDataSource
        #druid相关配置
        druid:
          #监控统计拦截的filters
          filters: stat
          driver-class-name: com.mysql.jdbc.Driver
          #基本属性
          url: jdbc:mysql://127.0.0.1:3306/test?charset=utf8mb4&useSSL=true
          username: root
          password: Root@123
          #配置初始化大小/最小/最大
          initial-size: 1
          min-idle: 1
          max-active: 20
          #获取连接等待超时时间
          max-wait: 60000
          #间隔多久进行一次检测，检测需要关闭的空闲连接
          time-between-eviction-runs-millis: 60000
          #一个连接在池中最小生存的时间
          min-evictable-idle-time-millis: 300000
          validation-query: SELECT 'x'
          test-while-idle: true
          test-on-borrow: false
          test-on-return: false
          #打开PSCache，并指定每个连接上PSCache的大小。oracle设为true，mysql设为false。分库分表较多推荐设置为false
          pool-prepared-statements: false
          max-pool-prepared-statement-per-connection-size: 20

mybatis:
  mapper-locations: classpath:mapping/*.xml
  type-aliases-package: com.example.smybatis.model

#pagehelper
pagehelper:
    helperDialect: mysql
    reasonable: true
    supportMethodsArguments: true
    params: count=countSql
    returnPageInfo: check

同时我们把项目中需要用到的文件夹都建了，如下

=========================第三部分：自动生成代码============================

我们在generator文件夹下面新增自动生成代码的配置文件generatorConfig.xml，内容如下

<?xml version="1.0" encoding="UTF-8"?>

<!DOCTYPE generatorConfiguration

        PUBLIC "-//mybatis.org//DTD MyBatis Generator Configuration 1.0//EN"

        "http://mybatis.org/dtd/mybatis-generator-config_1_0.dtd">

<generatorConfiguration>

    <!-- 数据库驱动:选择你的本地硬盘上面的数据库驱动包-->

    <classPathEntry  location="E:/work/jar/mysql-connector-java-5.0.7-bin.jar"/>

    <context id="DB2Tables"  targetRuntime="MyBatis3">

        <commentGenerator>

            <property name="suppressDate" value="true"/>

            <!-- 是否去除自动生成的注释 true：是 ： false:否 -->

            <property name="suppressAllComments" value="true"/>

        </commentGenerator>

        <!--数据库链接URL，用户名、密码 -->

        <jdbcConnection driverClass="com.mysql.jdbc.Driver" connectionURL="jdbc:mysql://127.0.0.1:3306/test?charset=utf8mb4" userId="root" password="Root@123">

        </jdbcConnection>

        <javaTypeResolver>

            <property name="forceBigDecimals" value="false"/>

        </javaTypeResolver>

        <!-- 生成模型的包名和位置-->

        <javaModelGenerator targetPackage="com.example.smybatis.model" targetProject="src/main/java">

            <property name="enableSubPackages" value="true"/>

            <property name="trimStrings" value="true"/>

        </javaModelGenerator>

        <!-- 生成映射文件的包名和位置-->

        <sqlMapGenerator targetPackage="mapping" targetProject="src/main/resources">

            <property name="enableSubPackages" value="true"/>

        </sqlMapGenerator>

        <!-- 生成DAO的包名和位置-->

        <javaClientGenerator type="XMLMAPPER" targetPackage="com.example.smybatis.mapper" targetProject="src/main/java">

            <property name="enableSubPackages" value="true"/>

        </javaClientGenerator>

        <!-- 要生成的表 tableName是数据库中的表名或视图名 domainObjectName是实体类名-->

        <table tableName="person" domainObjectName="Person" enableCountByExample="false" enableUpdateByExample="false" enableDeleteByExample="false" enableSelectByExample="false" selectByExampleQueryId="false"></table>

    </context>

</generatorConfiguration>

注意的是：一定要引入数据库连接jar包，要不然会报错

先在数据库建表，这块跟jpa不太一样了哈，jpa是建立java类，然后自动建表，这块是因为要根据表生成相对于的实体类和map文件，所以要先建立表

CREATE TABLE `person` (
  `id` INT(11) NOT NULL,
  `age` INT(11) DEFAULT NULL,
  `name` VARCHAR(255) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=INNODB DEFAULT CHARSET=utf8

1）点击run-Edit Configurations 

2）添加配置

3）运行

运行日志如下

我们再来看下工程结构，生成了新文件

我们来看一下文件的内容

1）model文件夹中的Person.java

package com.example.smybatis.model;

public class Person {
    private Integer id;

    private Integer age;

    private String name;

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public Integer getAge() {
        return age;
    }

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

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name == null ? null : name.trim();
    }
}

2）mapper文件夹中的PersonMapper.java

package com.example.smybatis.mapper;

import com.example.smybatis.model.Person;

public interface PersonMapper {
    int deleteByPrimaryKey(Integer id);

    int insert(Person record);

    int insertSelective(Person record);

    Person selectByPrimaryKey(Integer id);

    int updateByPrimaryKeySelective(Person record);

    int updateByPrimaryKey(Person record);
}

嗯，默认生成了好多方法

3）mapping文件夹中的PersonMapper.xml

<?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.smybatis.mapper.PersonMapper" >
  <resultMap id="BaseResultMap" type="com.example.smybatis.model.Person" >
    <id column="id" property="id" jdbcType="INTEGER" />
    <result column="age" property="age" jdbcType="INTEGER" />
    <result column="name" property="name" jdbcType="VARCHAR" />
  </resultMap>
  <sql id="Base_Column_List" >
    id, age, name
  </sql>
  <select id="selectByPrimaryKey" resultMap="BaseResultMap" parameterType="java.lang.Integer" >
    select 
    <include refid="Base_Column_List" />
    from person
    where id = #{id,jdbcType=INTEGER}
  </select>
  <delete id="deleteByPrimaryKey" parameterType="java.lang.Integer" >
    delete from person
    where id = #{id,jdbcType=INTEGER}
  </delete>
  <insert id="insert" parameterType="com.example.smybatis.model.Person" >
    insert into person (id, age, name
      )
    values (#{id,jdbcType=INTEGER}, #{age,jdbcType=INTEGER}, #{name,jdbcType=VARCHAR}
      )
  </insert>
  <insert id="insertSelective" parameterType="com.example.smybatis.model.Person" >
    insert into person
    <trim prefix="(" suffix=")" suffixOverrides="," >
      <if test="id != null" >
        id,
      </if>
      <if test="age != null" >
        age,
      </if>
      <if test="name != null" >
        name,
      </if>
    </trim>
    <trim prefix="values (" suffix=")" suffixOverrides="," >
      <if test="id != null" >
        #{id,jdbcType=INTEGER},
      </if>
      <if test="age != null" >
        #{age,jdbcType=INTEGER},
      </if>
      <if test="name != null" >
        #{name,jdbcType=VARCHAR},
      </if>
    </trim>
  </insert>
  <update id="updateByPrimaryKeySelective" parameterType="com.example.smybatis.model.Person" >
    update person
    <set >
      <if test="age != null" >
        age = #{age,jdbcType=INTEGER},
      </if>
      <if test="name != null" >
        name = #{name,jdbcType=VARCHAR},
      </if>
    </set>
    where id = #{id,jdbcType=INTEGER}
  </update>
  <update id="updateByPrimaryKey" parameterType="com.example.smybatis.model.Person" >
    update person
    set age = #{age,jdbcType=INTEGER},
      name = #{name,jdbcType=VARCHAR}
    where id = #{id,jdbcType=INTEGER}
  </update>
</mapper>

至此，第一阶段结束了，下篇讲解mybatis数据库操作