Spring和MyBatis的整合
思路
- 需要spring通过单例方式管理SqlSessionFactory。
- spring和mybatis整合生成代理对象，使用SqlSessionFactory创建SqlSession。（spring和mybatis整合自动完成）
- 持久层的mapper都需要由spring进行管理。
整合环境
创建一个新的maven工程项目
在pom文件中添加项目依赖
mybatis和spring的整合包：早期ibatis和spring整合是由spring官方提供，mybatis和spring整合由mybatis提供。
<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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>cn.company</groupId>
<artifactId>spring_mybatis</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>war</packaging>
<dependencies>
<!-- 单元测试所需jar包 -->
<!-- https://mvnrepository.com/artifact/junit/junit -->
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
<scope>test</scope>
</dependency>
<!-- mybatis -->
<!-- https://mvnrepository.com/artifact/org.mybatis/mybatis -->
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.5.4</version>
</dependency>
<!-- mybatis-spring整合包 -->
<!-- https://mvnrepository.com/artifact/org.mybatis/mybatis-spring -->
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis-spring</artifactId>
<version>2.0.4</version>
</dependency>
<!-- 日志jar包 -->
<!-- https://mvnrepository.com/artifact/log4j/log4j -->
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>1.2.17</version>
</dependency>
<!-- mysql -->
<!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.19</version>
</dependency>
<!-- springmvc的jar包 -->
<!-- https://mvnrepository.com/artifact/org.springframework/spring-webmvc -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>5.2.4.RELEASE</version>
</dependency>
<!-- spring的jar包 -->
<!-- https://mvnrepository.com/artifact/org.springframework/spring-core -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-core</artifactId>
<version>5.2.4.RELEASE</version>
</dependency>
<!--spring test -->
<!-- https://mvnrepository.com/artifact/org.springframework/spring-test -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-test</artifactId>
<version>5.2.4.RELEASE</version>
<scope>test</scope>
</dependency>
<!-- 数据库连接池,commons-dbcp -->
<!-- https://mvnrepository.com/artifact/commons-dbcp/commons-dbcp -->
<dependency>
<groupId>commons-dbcp</groupId>
<artifactId>commons-dbcp</artifactId>
<version>1.4</version>
</dependency>
<!-- spring-jdbc:提供了对jdbc模板的支持 -->
<!-- https://mvnrepository.com/artifact/org.springframework/spring-jdbc -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-jdbc</artifactId>
<version>5.2.4.RELEASE</version>
</dependency>
</dependencies>
</project>
数据库参数配置文件db.properties
jdbc.driver=com.mysql.cj.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/mybatis?serverTimezone=Asia/Shanghai&useUnicode=true&characterEncoding=utf-8
jdbc.username=root
jdbc.password=root
日志文件参数配置log4j.properties
# Global logging configuration
log4j.rootLogger=DEBUG ,stdout
# Console output...
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern==%5p [%t] - %m%n
添加spring配置文件applicationContext.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"
xmlns:tx="http://www.springframework.org/schema/tx"
xmlns:jdbc="http://www.springframework.org/schema/jdbc"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xsi:schemaLocation="
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.3.xsd
http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.3.xsd
http://www.springframework.org/schema/jdbc http://www.springframework.org/schema/jdbc/spring-jdbc-4.3.xsd
http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.3.xsd
http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.3.xsd
http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd">
<!--加载数据库配置文件 -->
<context:property-placeholder
location="classpath:db.properties" />
<!--数据源，使用dbcp -->
<bean id="dataSource"
class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
<property name="driverClassName" value="${jdbc.driver}" />
<property name="url" value="${jdbc.url}" />
<property name="username" value="${jdbc.username}" />
<property name="password" value="${jdbc.password}" />
<property name="maxActive" value="10" />
<property name="maxIdle" value="5" />
</bean>
<!-- sqlSessinFactory的配置 -->
<bean id="sqlSessionFactory"
class="org.mybatis.spring.SqlSessionFactoryBean">
<!--加载mybatis配置文件 -->
<property name="configLocation"
value="mybatis/SqlMapConfig.xml" />
<!-- 数据源 -->
<property name="dataSource" ref="dataSource" />
</bean>
</beans>
添加mybatis配置文件SqlMapConfig.xml
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
<settings>
<!-- 指定 MyBatis 所用日志的具体实现，未指定时将自动查找-->
<setting name="logImpl" value="LOG4J"/>
</settings>
<!-- 别名定义 -->
<typeAliases>
<!-- 批量别名定义
指定包名，mybatis自动扫描包中的po类，自动定义别名，别名就是类名（首字母大写或小写都可以）
-->
<package name="cn.itcast.ssm.po"/>
</typeAliases>
<!-- 加载 映射文件 -->
<mappers>
<mapper resource="sqlmap/User.xml"/>
<!-- 批量加载mapper
指定mapper接口的包名，mybatis自动扫描包下边所有mapper接口进行加载
遵循一些规范：需要将mapper接口类名和mapper.xml映射文件名称保持一致，且在一个目录 中
上边规范的前提是：使用的是mapper代理方法
和spring整合后，使用mapper扫描器，这里不需要配置了
-->
<!-- <package name="cn.itcast.ssm.mapper"/> -->
</mappers>
</configuration>
原始dao开发（和spring整合后）
User.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="test">
<select id="findUserById" resultType="User" parameterType="int">
select * from user where id=#{id}
</select>
</mapper>
在SqlMapConfig.xml中加载User.xml
pojo类和dao接口
package cn.itcast.ssm.po;
import java.util.Date;
/**
*用户类
* @author 86182
*
*/
public class User {
// 属性名和数据库表的字段对应
private int id;
private String username;// 用户姓名
private String sex;// 性别
private Date birthday;// 生日
private String address;// 地址
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getSex() {
return sex;
}
public void setSex(String sex) {
this.sex = sex;
}
public Date getBirthday() {
return birthday;
}
public void setBirthday(Date birthday) {
this.birthday = birthday;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
public String toString() {
return "User [id=" + id + ", username=" + username + ", sex=" + sex + ", birthday=" + birthday + ", address="
+ address + "]";
}
}
package cn.itcast.ssm.dao;
import cn.itcast.ssm.po.User;
/**
* UserDao接口类
* @author 86182
*
*/
public interface UserDao {
/*
* 根据id查找用户信息
*/
public User findUserById(int id) throws Exception;
}
dao接口实现类需要注入SqlSessoinFactory，通过spring进行注入。
这里spring声明配置方式，配置dao的bean：
让UserDaoImpl实现类继承SqlSessionDaoSupport
因为抽象类org.mybatis.spring.support.SqlSessionDaoSupport提供SqlSession。
package cn.itcast.ssm.dao;
import org.apache.ibatis.session.SqlSession;
import org.mybatis.spring.support.SqlSessionDaoSupport;
import cn.itcast.ssm.po.User;
/**
* UserDao接口实现类
* @author 86182
*
*/
public class UserDaoImpl extends SqlSessionDaoSupport implements UserDao {
/*
* 通过id查找用户信息
*/
public User findUserById(int id) throws Exception {
//继承SqlSessionDaoSupport，通过this.getSqlSession()得到sqlSessoin
SqlSession sqlSession=this.getSqlSession();
//
User user=sqlSession.selectOne("test.findUserById",id);
//方法结束，关闭数据库连接，无需手动释放资源，关闭SqlSession
return user;
}
}
在applicationContext.xml中配置dao
<?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"
xmlns:tx="http://www.springframework.org/schema/tx"
xmlns:jdbc="http://www.springframework.org/schema/jdbc"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xsi:schemaLocation="
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.3.xsd
http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.3.xsd
http://www.springframework.org/schema/jdbc http://www.springframework.org/schema/jdbc/spring-jdbc-4.3.xsd
http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.3.xsd
http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.3.xsd
http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd">
<!--加载数据库配置文件 -->
<context:property-placeholder
location="classpath:db.properties" />
<!--数据源，使用dbcp -->
<bean id="dataSource"
class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
<property name="driverClassName" value="${jdbc.driver}" />
<property name="url" value="${jdbc.url}" />
<property name="username" value="${jdbc.username}" />
<property name="password" value="${jdbc.password}" />
<!-- 连接池最大数量 -->
<property name="maxActive" value="10" />
<!--连接池最大空闲 -->
<property name="maxIdle" value="5" />
</bean>
<!-- sqlSessinFactory的配置 -->
<bean id="sqlSessionFactory"
class="org.mybatis.spring.SqlSessionFactoryBean">
<!--加载mybatis配置文件 -->
<property name="configLocation"
value="mybatis/SqlMapConfig.xml" />
<!-- 数据源 -->
<property name="dataSource" ref="dataSource" />
</bean>
<!--原始dao接口 -->
<bean id="userDao" class="cn.itcast.ssm.dao.UserDaoImpl">
<!-- spring注入sqlSessionFactory -->
<property name="sqlSessionFactory" ref="sqlSessionFactory"/>
</bean>
</beans>
mapper代理开发
创建mapper.java和mapper.xml
package cn.itcast.ssm.mapper;
import cn.itcast.ssm.po.User;
public interface UserMapper {
/*
* 根据id查找用户信息
*/
public User findUserById(int id) throws Exception;
}
<?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="cn.itcast.ssm.mapper.UserMapper">
<select id="findUserById" resultType="User" parameterType="int">
select * from user where id=#{id}
</select>
</mapper>
通过MapperFactoryBean创建代理对象
在applicationContext.xml中添加如下代码
<!--mapper配置,
MapperFactoryBean:根据mapper接口生成代理对象
-->
<bean id="userMapper" class="org.mybatis.spring.mapper.MapperFactoryBean">
<!-- mapperInterface:指定mapper接口 -->
<property name="mapperInterface" value="cn.itcast.ssm.mapper.UserMapper"/>
<!-- spring注入sqlSessionFactory -->
<property name="sqlSessionFactory" ref="sqlSessionFactory" />
</bean>
测试程序及结果
package cn.itcast.ssm.test;
import org.junit.Before;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import cn.itcast.ssm.mapper.UserMapper;
import cn.itcast.ssm.po.User;
public class UserMapperTest {
private ApplicationContext ac;
/*
* 得到spring容器
*/
@Before
public void setUp() throws Exception {
String configLocation = "classpath:applicationContext.xml";
ac = new ClassPathXmlApplicationContext(configLocation);
}
@Test
public void testFindUserById() throws Exception {
UserMapper userMapper=ac.getBean("userMapper",UserMapper.class);
User user=userMapper.findUserById(1);
System.out.println(user);
}
}
控制台输入如下结果：
通过MapperFactoryBean创建代理对象，需要针对每个mapper进行配置，麻烦。
优化方法
通过MapperScannerConfigurer进行mapper扫描
在applicationContext.xml中添加如下代码
<!-- mapper批量扫描，从mapper包中扫描出mapper接口,自动创建代理对象斌给在spring容器中注册。
遵循规范：将mapper.java和mapper.xml映射文件名称保持一致，并且在一个目录中。
自动扫描出来的mapper的bean和id为mapper类名（首字母小写）-->
<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
<!-- 指定扫描的包名 ,
如果扫描多个包，每个包中间使用英文输入下的逗号分隔。-->
<property name="basePackage" value="cn.itcast.ssm.mapper" />
<property name="sqlSessionFactoryBeanName" value="sqlSessionFactory" />
</bean>
去除如下配置
执行测试程序
package cn.itcast.ssm.test;
import org.junit.Before;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import cn.itcast.ssm.mapper.UserMapper;
import cn.itcast.ssm.po.User;
public class UserMapperTest {
private ApplicationContext ac;
/*
* 得到spring容器
*/
@Before
public void setUp() throws Exception {
String configLocation = "classpath:applicationContext.xml";
ac = new ClassPathXmlApplicationContext(configLocation);
}
@Test
public void testFindUserById() throws Exception {
UserMapper userMapper=ac.getBean("userMapper",UserMapper.class);
User user=userMapper.findUserById(1);
System.out.println(user);
}
}
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