spring boot 整合 mybatis 以及原理

2023-08-18 22:11:28

同上一篇文章一样，spring boot 整合 mybatis过程中没有看见SqlSessionFactory，sqlsession（sqlsessionTemplate），就连在spring框架整合 mybatis时的SqlSessionFactoryBean都没看到，那spring boot 把这些参数都放在了 mybatis-spring boot autoconfigure.jar 包中的MybatisAutoConfiguration 这个类中，使用 @ConditionalOnMissingBean这个注解，当环境中缺少 sqlsessionFactory sqlsessionTemplate时会自动注入

Example

使用spring boot 的starter pom

需要导入 mybatis-spring-boot-starter 和数据库连接相关的配置

pom.xml

<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.ibigsea</groupId>
<artifactId>bootdao</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>bootdao</name>
<url>http://maven.apache.org</url>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<boot.version>1.3.1.RELEASE</boot.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
<version>${boot.version}</version>
</dependency>
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
<version>1.1.1</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.38</version>
</dependency>
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>druid</artifactId>
<version>1.0.5</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<version>${boot.version}</version>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>

是不是很方便,mybatis的starter pom里面依赖了mybatis和spring相关的jar

只需导入一个就OK了

这里采用的是阿里巴巴的druid数据连接池

为了方便使用 yml配置文件

application.yml

---
spring:
profiles : dev
datasource:
name: mydb
type: com.alibaba.druid.pool.DruidDataSource
url: jdbc:mysql://127.0.0.1:3306/mytestdb
username: root
password: 123456
driver-class-name: com.mysql.jdbc.Driver
minIdle: 1
maxActive: 2
initialSize: 1
timeBetweenEvictionRunsMillis: 3000
minEvictableIdleTimeMillis: 300000
validationQuery: SELECT 'ZTM' FROM DUAL
testWhileIdle: true
testOnBorrow: false
testOnReturn: false
mybatis:
mapperLocations: classpath*:com/ibigsea/bootdao/mapper/*.xml
typeAliasesPackage: com.ibigsea.bootdao.entity

User.java

package com.ibigsea.bootdao.entity;
import java.io.Serializable;
public class User implements Serializable {
private static final long serialVersionUID = 8809101560720973267L;
private Integer id;
private String userName;
private Integer age;
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
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;
}
@Override
public String toString() {
return "User [id=" + id + ", userName=" + userName + ", age=" + age + "]";
}
}

UserMapper.java

package com.ibigsea.bootdao.mapper;
import java.util.List;
import org.apache.ibatis.annotations.Mapper;
import com.ibigsea.bootdao.entity.User;
@Mapper
public interface UserMapper {
int save(User user);
User selectById(Integer id);
int updateById(User user);
int deleteById(Integer id);
List<User> queryAll();
}

<p>UserMapper.xml</p>

<?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.ibigsea.bootdao.mapper.UserMapper" >
<insert id="save" parameterType="com.ibigsea.bootdao.entity.User">
insert into t_user(username,age) values(#{userName,jdbcType=VARCHAR},#{age,jdbcType=NUMERIC})
</insert>
<select id="selectById" resultType="com.ibigsea.bootdao.entity.User">
select * from t_user where id = #{id,jdbcType=NUMERIC}
</select>
<update id="updateById" parameterType="com.ibigsea.bootdao.entity.User">
update t_user set
username = #{userName,jdbcType=VARCHAR} ,
age = #{age,jdbcType=NUMERIC}
where id = #{id,jdbcType=NUMERIC}
</update>
<delete id="deleteById">
delete from t_user where id = #{id,jdbcType=NUMERIC}
</delete>
<select id="queryAll" resultType="com.ibigsea.bootdao.entity.User">
select * from t_user
</select>
</mapper>