整合Mybatis(Spring学习笔记十二)

一、导入相关的包

junit 包 Mybatis包 mysql数据库包 Spring相关的包 Aop相关的包

Mybatis-Spring包（现在就来学这个）

提示jdk版本不一致的朋友记得 jdk8只支持spring到5.x 所以如果导入的spring(spring-webmvc spring-jdbc)大于5.x 就需要降级或者安装jdk17否则就会报错；jdk8跟着我导入的包的版本来是没问题的

配置文件如下：

<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/maven-v4_0_0.xsd"><modelVersion>4.0.0</modelVersion><parent><groupId>org.example</groupId><artifactId>SpringFather</artifactId><version>1.0-SNAPSHOT</version></parent><artifactId>SpringSon10</artifactId><packaging>war</packaging><name>SpringSon10 Maven Webapp</name><url>http://maven.apache.org</url><dependencies><dependency><groupId>junit</groupId><artifactId>junit</artifactId><version>3.8.1</version><scope>test</scope></dependency><!--导入junit支持--><dependency><groupId>junit</groupId><artifactId>junit</artifactId><version>3.8.1</version></dependency><!--导入AOP支持--><!-- https://mvnrepository.com/artifact/org.aspectj/aspectjweaver --><dependency><groupId>org.aspectj</groupId><artifactId>aspectjweaver</artifactId><version>1.8.13</version></dependency><!--导入mysql支持        --><!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java --><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><version>5.1.47</version></dependency><!--导入Mybatis支持        --><!-- https://mvnrepository.com/artifact/org.mybatis/mybatis --><dependency><groupId>org.mybatis</groupId><artifactId>mybatis</artifactId><version>3.5.2</version></dependency><!--导入Spring支持        --><!-- https://mvnrepository.com/artifact/org.springframework/spring-webmvc --><dependency><groupId>org.springframework</groupId><artifactId>spring-webmvc</artifactId><version>5.1.9.RELEASE</version></dependency><!--Spring操作数据库的话还需要导入一个spring-jdbc 支持    --><!-- https://mvnrepository.com/artifact/org.springframework/spring-jdbc --><dependency><groupId>org.springframework</groupId><artifactId>spring-jdbc</artifactId><version>5.1.9.RELEASE</version></dependency><!--Mybatis和Spring整合的包--><!-- https://mvnrepository.com/artifact/org.mybatis/mybatis-spring --><dependency><groupId>org.mybatis</groupId><artifactId>mybatis-spring</artifactId><version>2.0.2</version></dependency><!--导入lombok包好写实体类的时候偷懒--><dependency><groupId>org.projectlombok</groupId><artifactId>lombok</artifactId><version>1.18.30</version></dependency><!--导入log4j相关依赖--><!-- https://mvnrepository.com/artifact/log4j/log4j --><dependency><groupId>log4j</groupId><artifactId>log4j</artifactId><version>1.2.17</version></dependency><dependency><groupId>junit</groupId><artifactId>junit</artifactId><version>4.13.2</version><scope>test</scope></dependency></dependencies><build><finalName>SpringSon10</finalName><!--解决配置文件无法导出或生效的问题（一般加在父工程）--><resources><resource><directory>src/main/resources</directory><includes><include>**/*.properties</include><include>**/*.xml</include></includes><filtering>true</filtering></resource><resource><directory>src/main/java</directory><includes><include>**/*.properties</include><include>**/*.xml</include></includes><filtering>true</filtering></resource></resources></build>
</project>

二、回忆一下Mybatis怎么实现的

创建实体类

package com.li.pojo;import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;@AllArgsConstructor
@NoArgsConstructor
@Data
public class User {private int id;private String name;private String pwd;
}

创建增删改查接口

package com.li.dao;import com.li.pojo.User;import java.util.List;public interface UserMapper {List<User> selectAll();
}

创建工具类获取sqlSessionFactory

package com.li.utils;import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;import java.io.IOException;
import java.io.InputStream;public class MybatisUtils {//官网上有三段代码拿来用 工具类的作用就是得到SqlSessionprivate static final SqlSessionFactory sqlSessionFactory;static{try {//获取SqlSessionFactory对象String resource = "mybatis-config.xml";InputStream inputStream = Resources.getResourceAsStream(resource);sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);} catch (IOException e) {throw new RuntimeException(e);}}//获取SqlSessionpublic static SqlSession getSqlSession(){return sqlSessionFactory.openSession();}
}

创建接口Mapper.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapperPUBLIC "-//mybatis.org//DTD Mapper 3.0//EN""http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<!--上面是头文件不管-->
<!--namespace等于绑定一个对应的Mapper接口 我这里是UserMapper接口-->
<mapper namespace="com.li.dao.UserMapper">
<!--    这里没有写sql语句--><select id="selectAll" resultType="user">select *from mybatis1.user</select>
</mapper>

原来的mybatis-config.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configurationPUBLIC "-//mybatis.org//DTD Config 3.0//EN""http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration><!--通过properties标签引入外部配置文件--><properties resource="db.properties"/><!--给实体类取别名--><typeAliases><package name="com.li.pojo"/></typeAliases><environments default="development"><environment id="development"><transactionManager type="JDBC"/><dataSource type="POOLED"><property name="driver" value="${driver}"/><property name="url" value="${urlName}"/><property name="username" value="${username}"/><property name="password" value="${password}"/></dataSource></environment></environments><!--    绑定mapper--><mappers><mapper resource="com/li/dao/UserMapper.xml"/><!--&lt;!&ndash;        &lt;!&ndash;也可以通过class绑定mapper&ndash;&gt;--><!--        <mapper class="com.li.mapper.UserMapper"/>--><!--&lt;!&ndash;        &ndash;&gt;&ndash;&gt;--></mappers></configuration>

和mybatis-config.xml相对应的配置文件

driver=com.mysql.jdbc.Driver
urlName=jdbc:mysql://localhost:3306/mybatis1?useSSL=false&useUnicode=true&characterEncoding=UTF-8
username=root
password=root

测试类测试能不能跑通

package com.li.dao;import com.li.pojo.User;
import com.li.utils.MybatisUtils;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;public class Testgo {@Testpublic void test1(){SqlSession sqlSession = MybatisUtils.getSqlSession();UserMapper mapper = sqlSession.getMapper(UserMapper.class);for (User user : mapper.selectAll()) {System.out.println(user);}sqlSession.close();}
}

目录结构

三、Mybatis-Spring

1、什么是Mybatis-spring

2、编写Mybatis-spring的xml配置文件

直接用spring的配置文件格式

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xmlns:aop="http://www.springframework.org/schema/aop"xsi:schemaLocation="http://www.springframework.org/schema/beanshttps://www.springframework.org/schema/beans/spring-beans.xsdhttp://www.springframework.org/schema/aophttps://www.springframework.org/schema/aop/spring-aop.xsd"></beans>

配置数据库连接的数据,相当于Mybatis的连接数据库那一段

    <!--DataSource:使用Spring的数据源替换Mybatis的配置    还可以用c3p0  dbcp  druid--><!--这里相当于配置连接数据库--><bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource"><property name="driverClassName" value="com.mysql.jdbc.Driver"/><property name="url" value="jdbc:mysql://localhost:3306/mybatis1?useSSL=true&amp;useUnicode=true&amp;characterEncoding=UTF-8"/><property name="username" value="root"/><property name="password" value="root"/></bean>

相当于这一段

  <environments default="development"><environment id="development"><transactionManager type="JDBC"/><dataSource type="POOLED"><property name="driver" value="${driver}"/><property name="url" value="${urlName}"/><property name="username" value="${username}"/><property name="password" value="${password}"/></dataSource></environment></environments>

得到sqlSessionFactory

  <!--得到sqlSessionFactory    --><bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean"><!--这里 ref后面值就是我们上面配置的数据库来连接的id值       --><property name="dataSource" ref="dataSource"/><!--这里可以实现Mybatis配置文件里的所有东西，基本上就可以不要mybatis配置文件了，但是有的时候mybatis配置文件还是有一定的作用一般会把取别名和设置放在mybatis的配置文件中去做--><!--绑定Mybatis的配置文件--><property name="configLocation" value="classpath:mybatis-config.xml"/><!--也可以注册mapper映射器--><property name="mapperLocations" value="classpath:com/li/dao/UserMapper.xml"/></bean>

配置文件之前相当于下面这一段

package com.li.utils;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;import java.io.IOException;
import java.io.InputStream;public class MybatisUtils {//官网上有三段代码拿来用 工具类的作用就是得到SqlSessionprivate static final SqlSessionFactory sqlSessionFactory;static{try {//获取SqlSessionFactory对象String resource = "mybatis-config.xml";InputStream inputStream = Resources.getResourceAsStream(resource);sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);} catch (IOException e) {throw new RuntimeException(e);}}//获取SqlSessionpublic static SqlSession getSqlSession(){return sqlSessionFactory.openSession();}
}

配置文件下面那两段相当于mybatis核心配置文件中的配置之类的（有一一对应的property 设置）

得到sqlSession 在mybatis-spring中叫sqlSessionTemplat

  <!--得到sqlSession,在mybatis-spring中叫sqlSessionTemplat可以简答的理解她两就是一个意思--><!--这里需要给SqlSessionTemplate注入一个参数    --><bean id="sqlSessionT" class="org.mybatis.spring.SqlSessionTemplate"><!--这里只能用构造器注入，因为没有set方法        --><constructor-arg index="0" ref="sqlSessionFactory"/></bean>

在mybatis中我们在配置文件中就可以写sql语句，但是这里链接Spring了之后配置是面向对象的，需要创建一个实现类来写sql语句

package com.li.dao;import com.li.pojo.User;
import org.mybatis.spring.SqlSessionTemplate;import java.util.List;public class UserMapperImpl implements UserMapper{//之前我们所有的操作都是用sqlSession来执行，现在我们用sqlSessionTemplat来执行的//使用spring需要注入，需要有set方法，spring万物皆注入private SqlSessionTemplate sqlSessionTemplate;public void setSqlSessionTemplate(SqlSessionTemplate sqlSessionTemplate) {this.sqlSessionTemplate = sqlSessionTemplate;}@Overridepublic List<User> selectAll() {//这里的操作就是和拿到SqlSession之后拿mapper的方法是一样的UserMapper mapper = sqlSessionTemplate.getMapper(UserMapper.class);return  mapper.selectAll();}
}

写完类之后就需要在配置文件中注入

 <!--注入写的拿到写sql语句的类--><bean id="userMapper" class="com.li.dao.UserMapperImpl"><!--得到sqlSessionTempla--><property name="sqlSessionTemplate" ref="sqlSessionTempla"/></bean>

配置完成之后我们来写测试类测试

package com.li.dao;import com.li.pojo.User;
import com.li.utils.MybatisUtils;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;public class Testgo {@Testpublic void test1(){//        SqlSession sqlSession = MybatisUtils.getSqlSession();
//
//        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
//
//        for (User user : mapper.selectAll()) {
//            System.out.println(user);
//        }
//
//        sqlSession.close();ApplicationContext context = new ClassPathXmlApplicationContext("spring-dao.xml");UserMapper mapper = context.getBean("userMapper", UserMapper.class);for (User user : mapper.selectAll()) {System.out.println(user);}}
}

完整的spring-dao.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xmlns:aop="http://www.springframework.org/schema/aop"xsi:schemaLocation="http://www.springframework.org/schema/beanshttps://www.springframework.org/schema/beans/spring-beans.xsdhttp://www.springframework.org/schema/aophttps://www.springframework.org/schema/aop/spring-aop.xsd"><!--DataSource:使用Spring的数据源替换Mybatis的配置    还可以用c3p0  dbcp  druid--><!--这里相当于配置连接数据库--><bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource"><property name="driverClassName" value="com.mysql.jdbc.Driver"/><property name="url" value="jdbc:mysql://localhost:3306/mybatis1?useSSL=false&amp;useUnicode=true&amp;characterEncoding=UTF-8"/><property name="username" value="root"/><property name="password" value="root"/></bean><!--得到sqlSessionFactory    --><bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean"><!--这里 ref后面值就是我们上面配置的数据库来连接的id值       --><property name="dataSource" ref="dataSource"/><!--这里可以实现Mybatis配置文件里的所有东西，基本上就可以不要mybatis配置文件了，但是有的时候mybatis配置文件还是有一定的作用一般会把取别名和设置放在mybatis的配置文件中去做--><!--绑定Mybatis的配置文件--><property name="configLocation" value="classpath:mybatis-config.xml"/><!--也可以注册mapper映射器--><property name="mapperLocations" value="classpath:com/li/dao/UserMapper.xml"/></bean><!--得到sqlSession,在mybatis-spring中叫sqlSessionTemplat可以简答的理解她两就是一个意思--><!--这里需要给SqlSessionTemplate注入一个参数    --><bean id="sqlSessionT" class="org.mybatis.spring.SqlSessionTemplate"><!--这里只能用构造器注入，因为没有set方法        --><constructor-arg index="0" ref="sqlSessionFactory"/></bean><!--注入写的拿到写sql语句的类--><bean id="userMapper" class="com.li.dao.UserMapperImpl"><!--得到sqlSessionTemplate--><property name="sqlSessionTemplate" ref="sqlSessionT"/></bean></beans>

需要注意的是UserMapper的配置文件不能把里面的sql语句部分删除，要不然会报

Invalid bound statement (not found) 的错

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapperPUBLIC "-//mybatis.org//DTD Mapper 3.0//EN""http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<!--上面是头文件不管-->
<!--namespace等于绑定一个对应的Mapper接口 我这里是UserMapper接口-->
<mapper namespace="com.li.dao.UserMapper">
<!--    这里没有写sql语句--><select id="selectAll" resultType="user">select *from mybatis1.user</select>
</mapper>