Spring和Mybatis整合

2023-09-11 阅读 27 评论 0

摘要：9. Spring和Mybatis整合 9.1 创建工程新建工程，导入所需jar包： <dependencies><dependency><groupId>org.mybatis</groupId><artifactId>mybatis</artifactId><version>3.4.1</vers

9. Spring和Mybatis整合

9.1 创建工程

新建工程，导入所需jar包：

<dependencies><!-- mybatis核心包 --><dependency><groupId>org.mybatis</groupId><artifactId>mybatis</artifactId><version>3.4.1</version></dependency><!-- mysql驱动包 --><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><version>5.1.29</version></dependency><!-- junit测试包 --><dependency><groupId>junit</groupId><artifactId>junit</artifactId><version>4.12</version></dependency><!--日志包--><dependency><groupId>org.slf4j</groupId><artifactId>slf4j-log4j12</artifactId><version>1.6.1</version></dependency><dependency><groupId>org.slf4j</groupId><artifactId>slf4j-api</artifactId><version>1.6.1</version></dependency><!--spring数据库--><dependency><groupId>org.springframework</groupId><artifactId>spring-jdbc</artifactId><version>4.3.11.RELEASE</version></dependency><!--aop--><dependency><groupId>org.springframework</groupId><artifactId>spring-aspects</artifactId><version>4.3.11.RELEASE</version></dependency><dependency><groupId>org.springframework</groupId><artifactId>spring-context</artifactId><version>4.3.11.RELEASE</version></dependency><!--spring-mybatis整合包--><dependency><groupId>org.mybatis</groupId><artifactId>mybatis-spring</artifactId><version>1.3.1</version></dependency>
<!--spring相关包--><dependency><groupId>org.springframework</groupId><artifactId>spring-webmvc</artifactId><version>4.3.11.RELEASE</version></dependency></dependencies><!--配置资源文件扫描，否则Mapper--><build><resources><resource><directory>src/main/java</directory><includes><include>**/*.xml</include></includes><filtering>true</filtering></resource><resource><directory>src/main/resources</directory><includes><include>**/*.xml</include><include>**/*.properties</include></includes></resource></resources></build>

工程完整目录如下：
在这里插入图片描述
jdbc.properties文件存放数据库连接信息：

jdbc.driver=com.mysql.jdbc.Driverjdbc.url=jdbc:mysql://localhost:3306/数据库?characterEncoding=utf-8jdbc.username=用户名jdbc.password=密码

log4j日志文件见1.6节

实体类Dept和Employee见1.3

MyBatis？映射文件DeptMapper.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"><mapper namespace="com.dao.DeptDAO"><insert id="addDept" parameterType="Dept" keyProperty="id" useGeneratedKeys="true" >insert into DEPT(NAME) values(#{name})</insert></mapper>

接口DeptDAO

package com.dao;
import com.pojo.Dept;
public interface DeptDAO {void addDept(Dept dept);
}

9.2 spring-mybatis整合

在spring与mybatis整合示例中，spring负责管理数据源、加载mybatis配置文件、mybatis的session和事务。

<?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:context="http://www.springframework.org/schema/context"xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.2.xsdhttp://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.2.xsd"><!--spring管理数据源--><context:property-placeholder location="classpath:jdbc.properties" ignore-unresolvable="true"/><bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource"><property name="driverClassName" value="${jdbc.driver}"/><property name="url" value="${jdbc.url}"/><property name="username" value="${jdbc.username}"/><property name="password" value="${jdbc.password}"/></bean>
</beans>

mybatis的配置文件中不再写Mapper映射文件的配置：

<?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><typeAliases><typeAlias type="com.pojo.Dept" alias="Dept"/><typeAlias type="com.pojo.Employee" alias="Employee"/></typeAliases></configuration>

spring中加载mybatis的配置文件

<!--spring管理session工厂--><bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean"><property name="dataSource" ref="dataSource"/><property name="mapperLocations" value="classpath:com/dao/mapper/*.xml"/><property name="configLocation" value="classpath:mybatis-config.xml"/></bean>

Springboot项目，省略mybatis配置文件的写法：

<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean"><property name="dataSource" ref="dataSource"/><property name="mapperLocations" value="classpath:dao/*.xml"/><property name="typeAliasesPackage" value="pojo"/><!--<property name="configLocation" value="classpath:mybatis-config.xml"/>--><property name="plugins"><array><bean class="com.github.pagehelper.PageHelper"><property name="properties"><value>dialect=mysqlreasonable=true</value></property></bean></array></property></bean>

9.2.1 dao的基本整合

编写DeptDAO的实现类：

package com.dao.impl;import com.dao.DeptDAO;import com.pojo.Dept;import org.mybatis.spring.support.SqlSessionDaoSupport;public class DeptDAOImpl extends SqlSessionDaoSupport implements DeptDAO{@Overridepublic void addDept(Dept dept) {super.getSqlSession().insert("com.dao.DeptDAO.addDept", dept);}}

DAO继承了spring的SqlSessionDaoSupport，SqlSessionDaoSupport中注入sessionFactory，负责管理session。

声明DeptDAO的bean

<bean id="deptDAO" class="com.dao.impl.DeptDAOImpl"><property name="sqlSessionFactory" ref="sqlSessionFactory"/></bean>

测试代码：

public class SpringTest {ApplicationContext ac = new ClassPathXmlApplicationContext("spring-mybatis.xml");@Testpublic void testDeptDAO() {DeptDAO deptDAO = (DeptDAO) ac.getBean("deptDAO");Dept dept = new Dept();dept.setName("abcdefg");deptDAO.addDept(dept);}
}

9.2.2 面向接口的整合

spring整合了哪些框架、mybatis的dao可以没有实现类，只写接口，要求对应的Mapper映射文件的namespace是接口的全路径。接口中方法名与sql语句的id一致。

接口EmployeeDAO

package com.dao;
import com.pojo.Employee;
import java.util.List;
/*** 本接口没有实现类*/
public interface EmployeeDAO {List<Employee> getAllDept();
}

映射文件：

映射文件EmployeeMapper.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"><!--注意namespace和接口全路径一致-->
<mapper namespace="com.dao.EmployeeDAO"><resultMap id="employeeMap" type="Employee"><id property="id" column="ID"/><result property="name" column="NAME"/><result property="job" column="JOB"/><result property="salary" column="SALARY"/><result property="hireDate" column="HIRE_DATE"/><result property="dept.id" column="DEPT_ID"/><result property="dept.name" column="DEPT_NAME"/></resultMap><!--注意语句的id与接口中的方法名一致--><select id="getAllDept" resultMap="employeeMap">select ID,NAME FROM EMPLOYEE</select></mapper>

spring中配置bean:

<!--面向接口的整合，EmployeeDAO接口没有实现类--><bean id="employeeDAO" class="org.mybatis.spring.mapper.MapperFactoryBean"><property name="mapperInterface" value="com.dao.EmployeeDAO"/><property name="sqlSessionFactory" ref="sqlSessionFactory"/></bean>

java groupingby？测试代码：

@Testpublic void testEmpDAO() {EmployeeDAO dao = (EmployeeDAO) ac.getBean("employeeDAO");List<Employee> list = dao.getAllDept();for (Employee employee : list) {System.out.println(employee.getName());}}

9.2.3 简化配置

Mybatis的接口可以没有实现类，当接口很多的时候，可以统一扫描，不需要每个接口都声明bean:

<!—dao接口包扫描器 --><bean class="org.mybatis.spring.mapper.MapperScannerConfigurer"><property name="basePackage" value="com.dao"/></bean>

注释掉7.2.2中employeeDAO的bean，运行测试代码一样可以成功。

简化：

当DAO的接口和Mapper映射文件在一个文件夹下，且命名一致的时候：
在这里插入图片描述
映射文件和接口的命名一样，只是文件拓展名不同，配置了上面的MapperScannerConfigurer后，可以省略sqlSessionFactory中配置文件的路径：

<!--spring管理session工厂--><bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean"><property name="dataSource" ref="dataSource"/><!--如果映射文件和接口在一个包下，并且命名一致，可以不写这句--><!--<property name="mapperLocations" value="classpath:com/dao/mapper/*.xml"/>--><property name="configLocation" value="classpath:mybatis-config.xml"/>
<property name="plugins"><array><bean class="com.github.pagehelper.PageHelper"><property name="properties"><value>dialect=mysqlreasonable=true</value></property></bean></array></property></bean>