MyBatis 之 各种依赖包

mybatis-spring从1.1升级到1.2所带来的dao层级的编写问题 我们可以先来看看mybatis-spring框架的1.1.1版本中关于SqlSessionDaoSupport的代码吧： package org.mybatis.spring.support; import static org.springframework.util.Assert.*; import org.apache.ibatis.session.SqlSession; import org.apache.ibatis.session.SqlSessionFactory; import org.mybatis.spring.SqlSessionTemplate; import org.springframework.beans.factory.annotation.Autowired; 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. * * @see #setSqlSessionFactory * @see #setSqlSessionTemplate * @see SqlSessionTemplate * @version $Id: SqlSessionDaoSupport.java 4885 2012-03-12 09:58:54Z simone.tripodi $ */ public abstract class SqlSessionDaoSupport extends DaoSupport { private SqlSession sqlSession; private boolean externalSqlSession; @Autowired(required = false) public final void setSqlSessionFactory(SqlSessionFactory sqlSessionFactory) { if (!this.externalSqlSession) { this.sqlSession = new SqlSessionTemplate(sqlSessionFactory); } } @Autowired(required = false) public final 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 final SqlSession getSqlSession() { return this.sqlSession; } /** * {@inheritDoc} */ protected void checkDaoConfig() { notNull(this.sqlSession, "Property 'sqlSessionFactory' or 'sqlSessionTemplate' are required"); } } 　　从上面的源码可以看出：在方法setSqlSessionFactory和setSqlSessionTemplate方法上面都标注有：“@Autowired(required = false)”这样的注解。 所以我们在编写dao层级代码的时候只需要dao直接继承SqlSessionDaoSupport，并标注注解@Repository，然后就可以使用类似的getSqlSession().selectList("User.selectUsers"); 这样的方法来使用它了，而且在spring的配置文件中的配置也比较少： <tx:annotation-driven transaction-manager="txManager" proxy-target-class="true"/> <bean id="txManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager"> <property name="dataSource" ref="dataSource"/> </bean> <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean"> <property name="dataSource" ref="dataSource"/> <property name="configLocation" value="classpath:mybatis-config.xml"/> </bean> 　　 　　但是升级到1.2之后，我们看看SqlSessionDaoSupport的源代码： 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} */ protected void checkDaoConfig() { notNull(this.sqlSession, "Property 'sqlSessionFactory' or 'sqlSessionTemplate' are required"); } } 　　 　　从上面的源码可以看出：在方法setSqlSessionFactory和setSqlSessionTemplate方法上面现在都没有标注有：“@Autowired(required = false)”这样的注解。 如果一些系统直接从mybatis-spring1.1.1升级到1.2版本的时候，就会出现问题。 在1.2版本下面有几种方式来使用： 第一种，基于注解： @Repository public class UserDao extends SqlSessionDaoSupport{ public List<User> userList() { return getSqlSession().selectList("User.selectUsers"); } @Override @Autowired public void setSqlSessionFactory(SqlSessionFactory sqlSessionFactory) { super.setSqlSessionFactory(sqlSessionFactory); } } 　　 　　我们自己重写set方法就可以了。在这种情况下spring的配置文件不需要修改。 第二章基于xml文件配置： public class UserDao extends SqlSessionDaoSupport { public List<User> userList() { return getSqlSession().selectList("User.selectUsers"); } } 　　 　　但是需要在spring的配置文件中增加这个UserDao的配置： <bean id="userDao" class="com.qunar.corp.paginator.dao.UserDao"> <property name="sqlSessionFactory" ref="sqlSessionFactory"/> </bean> 　　 　　第一种基于注解的配置，好处是不需要编写xml，但是这种比较容易侵入业务逻辑。 第二种基于xml配置，好处是不侵入业务逻辑，但是当dao的数量很多的时候，需要在xml中配置好多。