spring和mybatis的整合方式
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2022-04-26 18:42:17
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1.Dao类继承org.mybatis.spring.support.SqlSessionDaoSupport
Spring配置文件
<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean"> <property name="dataSource" ref="dataSource" /> <property name="configLocation" value="classpath:sqlMapConfig.xml"/> </bean> <bean id="sqlSession" class="org.mybatis.spring.SqlSessionTemplate"> <constructor-arg index="0" ref="sqlSessionFactory" /> </bean> <bean id="userDaoImpl" class="xx.yy.impl.UserDaoImpl"> <property name="sqlSessionTemplate" ref="sqlSession" /> <!--或者直接注入SqlSessionFactory实例,二者都指定时,SqlSessionFactory会失效 --> <!-- <property name="sqlSessionFactory" ref="sqlSessionFactory" /> --> </bean>
UserDaoImpl.java
public class UserDaoImpl extends SqlSessionDaoSupport implements UserDao { public User getUserById(User user) { return (User) getSqlSession().selectOne("xx.yy.User.getUser", user); } }
SqlSessionDaoSupport.java
/** * Copyright 2010-2015 the original author or authors. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package org.mybatis.spring.support; import static org.springframework.util.Assert.notNull; import org.apache.ibatis.session.SqlSession; import org.apache.ibatis.session.SqlSessionFactory; import org.mybatis.spring.SqlSessionTemplate; import org.springframework.dao.support.DaoSupport; /** * Convenient super class for MyBatis SqlSession data access objects. * It gives you access to the template which can then be used to execute SQL methods. * <p> * This class needs a SqlSessionTemplate or a SqlSessionFactory. * If both are set the SqlSessionFactory will be ignored. * <p> * {code Autowired} was removed from setSqlSessionTemplate and setSqlSessionFactory * in version 1.2.0. * * @author Putthibong Boonbong * * @see #setSqlSessionFactory * @see #setSqlSessionTemplate * @see SqlSessionTemplate * @version $Id$ */ public abstract class SqlSessionDaoSupport extends DaoSupport { private SqlSession sqlSession; private boolean externalSqlSession; public void setSqlSessionFactory(SqlSessionFactory sqlSessionFactory) { if (!this.externalSqlSession) { this.sqlSession = new SqlSessionTemplate(sqlSessionFactory); } } public void setSqlSessionTemplate(SqlSessionTemplate sqlSessionTemplate) { this.sqlSession = sqlSessionTemplate; this.externalSqlSession = true; } /** * Users should use this method to get a SqlSession to call its statement methods * This is SqlSession is managed by spring. Users should not commit/rollback/close it * because it will be automatically done. * * @return Spring managed thread safe SqlSession */ public SqlSession getSqlSession() { return this.sqlSession; } /** * {@inheritDoc} */ @Override protected void checkDaoConfig() { notNull(this.sqlSession, "Property 'sqlSessionFactory' or 'sqlSessionTemplate' are required"); } }
1>创建UserDaoImpl对象的时候,会调用父类中的setSqlSessionTemplate或者setSqlSessionFactory方法来注入sqlSession
2>UserDaoImpl的getUserById里面,直接调用getSqlSession()方法来获得之前注入的sqlSession对象
3>调用sqlSession的接口方法来执行具体的sql语句
2.不用继承SqlSessionDaoSupport,而是直接向Dao类中注入SqlSessionTemplate
(SqlSessionDaoSupport里面其实返回的就是SqlSessionTemplate对象)
UserDaoImpl.java
public class UserDaoImpl implements UserDao { public SqlSessionTemplate sqlSession; public User getUserById(User user) { return (User)sqlSession.selectOne("com.xxt.ibatis.dbcp.domain.User.getUser", user); } public void setSqlSession(SqlSessionTemplate sqlSession) { this.sqlSession = sqlSession; } }
Spring配置文件
<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean"> <property name="dataSource" ref="dataSource" /> <property name="configLocation" value="classpath:sqlMapConfig.xml"/> </bean> <bean id="sqlSession" class="org.mybatis.spring.SqlSessionTemplate"> <constructor-arg index="0" ref="sqlSessionFactory" /> </bean> <bean id="userDaoImpl" class="xx.yy.impl.UserDaoImpl"> <property name="sqlSession" ref="sqlSession" /> </bean>
1和2的整合方式差不太多,只是一个继承了SqlSessionDaoSupport,另一个直接注入SqlSessionTemplate
3.不直接使用SqlSession接口,而是使用org.mybatis.spring.mapper.MapperFactoryBean来自动生成映射器接口的代理实现,Dao里面直接调用Mapper接口来间接执行底层的sql语句
Spring配置文件
<!-- 引入jdbc配置文件 --> <context:property-placeholder location="jdbc.properties"/> <!--创建jdbc数据源 --> <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close"> <property name="driverClassName" value="${driver}"/> <property name="url" value="${url}"/> <property name="username" value="${username}"/> <property name="password" value="${password}"/> <property name="initialSize" value="${initialSize}"/> <property name="maxActive" value="${maxActive}"/> <property name="maxIdle" value="${maxIdle}"/> <property name="minIdle" value="${minIdle}"/> </bean> <!-- 创建SqlSessionFactory,同时指定数据源--> <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean"> <property name="dataSource" ref="dataSource" /> <!-- 如果采用注解的方式将sql语句配置在Mapper接口的对应方法前面,configLocation不需要配置 --> <beans:property name="configLocation" value="classpath:conf/mybatis-config.xml" /> </bean> <!--创建数据映射器,数据映射器必须为接口--> <bean id="userMapper" class="org.mybatis.spring.mapper.MapperFactoryBean"> <property name="mapperInterface" value="xx.yy.dao.UserMapper" /> <property name="sqlSessionFactory" ref="sqlSessionFactory" /> </bean> <bean id="userDaoImpl" class="xx.yy.dao.impl.UserDaoImpl"> <property name="userMapper" ref="userMapper"/> </bean>
UserMapper.java
public interface UserMapper { @Select("SELECT * FROM user WHERE id = #{userId}") User getUser(@Param("userId") long id); }
UserDaoImpl.java
public class UserDaoImpl implements UserDao { private UserMapper userMapper; public void setUserMapper(UserMapper userMapper) { this.userMapper = userMapper; } public User getUserById(User user) { return userMapper.getUser(user.getId()); } }
UserMapper.xml
<mapper namespace="xx.yy.dao.UserMapper"> <resultMap type="User" id="userMap"> <id property="id" column="id" /> <result property="name" column="name" /> <result property="password" column="password" /> <result property="createTime" column="createtime" /> </resultMap> <select id="getUser" parameterType="User" resultMap="userMap"> select * from user where id = #{id} </select> <mapper/>
4.如果Mapper接口比较多的时候,3.的spring配置文件里面要分别对每一个mapper增加配置,为了简化配置,可以使用org.mybatis.spring.mapper.MapperScannerConfigurer来自动扫描所有的mapper接口,并自动生成相应的mapper代理对象
spring配置文件
<!-- 引入jdbc配置文件 --> <context:property-placeholder location="jdbc.properties"/> <!--创建jdbc数据源 --> <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close"> <property name="driverClassName" value="${driver}"/> <property name="url" value="${url}"/> <property name="username" value="${username}"/> <property name="password" value="${password}"/> <property name="initialSize" value="${initialSize}"/> <property name="maxActive" value="${maxActive}"/> <property name="maxIdle" value="${maxIdle}"/> <property name="minIdle" value="${minIdle}"/> </bean> <!-- 创建SqlSessionFactory,同时指定数据源--> <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean"> <property name="dataSource" ref="dataSource" /> <!-- 如果采用注解的方式将sql语句配置在Mapper接口的对应方法前面,configLocation不需要配置 --> <beans:property name="configLocation" value="classpath:conf/mybatis-config.xml" /> </bean> <!--配置扫描器--> <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer"> <property name="basePackage" value="xx.yy.dao" /> <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory" /> </bean> </bean>
当然如果业务逻辑比较简单的话,可以在service类里面直接注入Mapper接口进行dao操作,也可以单独设计一层dao层,然后将mapper接口注入到dao类里面进行使用.
1,2直接面对的是SqlSession接口,而3,4根据mapper接口自动生成代理实现类,增加了mapper层,使我们直接面对mapper接口层进行dao操作,从而不用关注底层的SqlSession接口
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