spring 整合 mybatis 中数据源的几种配置方式(总结篇)

因为spring 整合mybatis的过程中， 有好几种整合方式，尤其是数据源那块，经常看到不一样的配置方式，总感觉有点乱，所以今天有空总结下。

　　一、采用org.mybatis.spring.mapper.MapperScannerConfigurer

　　其实逆向工程也是这种方式

　　1、数据源配配置文件

　2、DAO文件

 package com.jdd.mapper;
 import com.jdd.pojo.Employee;
 import java.util.List;
 public interface EmployeeMapper {
   public Employee getEmployeeById(int id);
   public List<Employee> findAllEmployees();
 }

　　3、Mapper.xml 文件

　　 <?xml version="." encoding="UTF-" ?>
 <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper .//EN"
 "http://mybatis.org/dtd/mybatis--mapper.dtd">
 <mapper namespace="com.jdd.mapper.EmployeeMapper">
   <select id="getEmployeeById" parameterType="int" resultType="com.jdd.pojo.Employee">
     <![CDATA[
       select * from employee where id = #{id};
     ]]>
   </select>
   <select id="findAllEmployees" resultType="com.jdd.pojo.Employee">
     <![CDATA[
       select * from employee where status='';
     ]]>
   </select>
 </mapper>

　　这样在service类里就可以直接注入dao接口了

 package com.jdd.service.impl;
 import com.jdd.mapper.EmployeeMapper;
 import com.jdd.pojo.Employee;
 import com.jdd.service.EmployeeService;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.stereotype.Service;
 import java.util.List;
 @Service("employeeService")
 public class EmployeeServiceImpl implements EmployeeService{
   @Autowired
   private EmployeeMapper employeeMapper;
   @Override
   public Employee getEmployeeById(int id) {
     return employeeMapper.getEmployeeById(id);
   }
   @Override
   public List<Employee> findAllEmployees() {
     return employeeMapper.findAllEmployees();
   }
 }

　　　　二、 采用抽象类org.mybatis.spring.support.SqlSessionDaoSupport， 给它注入 sqlSessionFactory的方式

　　1、数据源配置文件

　　 <?xml version="." encoding="UTF-"?>
 <beans xmlns="http://www.springframework.org/schema/beans"
   xmlns:context="http://www.springframework.org/schema/context" xmlns:p="http://www.springframework.org/schema/p"
   xmlns:aop="http://www.springframework.org/schema/aop" xmlns:tx="http://www.springframework.org/schema/tx"
   xmlns:xsi="http://www.w.org//XMLSchema-instance"
   xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-..xsd
   http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-..xsd
   http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-..xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-..xsd
   http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-..xsd">
   <!-- 加载配置文件 -->
   <context:property-placeholder location="classpath:resource/*.properties" />
   <!-- 数据库连接池 -->
   <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource"
     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="" />
     <property name="minIdle" value="" />
   </bean>
   <!-- sqlsessionFactory -->
   <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
     <property name="configLocation" value="classpath:mybatis/SqlMapConfig.xml"></property>
     <property name="dataSource" ref="dataSource"></property>
     <property name="mapperLocations" value="classpath:com/jdd/mapper/*.xml"></property>
   </bean>
 </beans>

　　2、baseDao类

 package com.jdd.dao;
 import org.apache.ibatis.session.SqlSessionFactory;
 import org.mybatis.spring.support.SqlSessionDaoSupport;
 import javax.annotation.Resource;
 public abstract class BaseDao extends SqlSessionDaoSupport {
   @Resource
   public void setSqlSessionFactory(SqlSessionFactory sqlSessionFactory) {
     super.setSqlSessionFactory(sqlSessionFactory);
   }
 }

　　3、接口 EmployeeDao.java 类

 package com.jdd.dao;
 import com.jdd.pojo.Employee;
 import java.util.List;
 public interface EmployeeDao {
   Employee getEmployeeById(int id);
   List<Employee> findAllEmployees();
 }

　　4、dao实现类 EmployeeDaoImpl

 package com.jdd.dao.impl;
 import com.jdd.dao.BaseDao;
 import com.jdd.dao.EmployeeDao;
 import com.jdd.pojo.Employee;
 import org.springframework.stereotype.Repository;
 import java.util.List;
 @Repository("employeeDao")
 public class EmployeeDaoImpl extends BaseDao implements EmployeeDao {
   @Override
   public Employee getEmployeeById(int id) {
     return this.getSqlSession().selectOne("com.jdd.dao.EmployeeDao.getEmployeeById", id);
   }
   @Override
   public List<Employee> findAllEmployees() {
     return this.getSqlSession().selectList("com.jdd.dao.EmployeeDao.findAllEmployees");
   }
 }

　　5、这样就可以在service类里注入 employeeDao了

　　三、采用 org.mybatis.spring.SqlSessionTemplate 模板类

　　1、数据源文件

 <?xml version="." encoding="UTF-"?>
 <beans xmlns="http://www.springframework.org/schema/beans"
   xmlns:context="http://www.springframework.org/schema/context" xmlns:p="http://www.springframework.org/schema/p"
   xmlns:aop="http://www.springframework.org/schema/aop" xmlns:tx="http://www.springframework.org/schema/tx"
   xmlns:xsi="http://www.w.org//XMLSchema-instance"
   xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-..xsd
   http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-..xsd
   http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-..xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-..xsd
   http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-..xsd">
   <!-- 加载配置文件 -->
   <context:property-placeholder location="classpath:resource/*.properties" />
   <!-- 数据库连接池 -->
     <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource"
     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="" />
     <property name="minIdle" value="" />
   </bean>
   <!-- sqlsessionFactory -->
   <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
     <property name="configLocation" value="classpath:mybatis/SqlMapConfig.xml"></property>
     <property name="dataSource" ref="dataSource"></property>
     <property name="mapperLocations" value="classpath:com/jdd/mapper/*.xml"></property>
   </bean>
   <bean id="sqlSessionTemplate" class="org.mybatis.spring.SqlSessionTemplate">
     <constructor-arg index="" ref="sqlSessionFactory"/>
   </bean>
 </beans>

　　2、 basedao.java 类

 package com.jdd.dao;
 import org.mybatis.spring.SqlSessionTemplate;
 import javax.annotation.Resource;
 public abstract class BaseDao {
   public SqlSessionTemplate sqlSessionTemplate;
   @Resource
   public void setSqlSessionTemplate(SqlSessionTemplate sqlSessionTemplate) {
     this.sqlSessionTemplate = sqlSessionTemplate;
   }
 }

　　3、接口 EmployeeDao.java 类　　

package com.jdd.dao;
 import com.jdd.pojo.Employee;
 import java.util.List;
 public interface EmployeeDao {
   Employee getEmployeeById(int id);
   List<Employee> findAllEmployees();
 }

　　4、dao实现类 EmployeeDaoImpl

 package com.jdd.dao.impl;
 import com.jdd.dao.BaseDao;
 import com.jdd.dao.EmployeeDao;
 import com.jdd.pojo.Employee;
 import org.springframework.stereotype.Repository;
 import java.util.List;
 @Repository("employeeDao")
 public class EmployeeDaoImpl extends BaseDao implements EmployeeDao {
   @Override
   public Employee getEmployeeById(int id) {
     return sqlSessionTemplate.selectOne("com.jdd.dao.EmployeeDao.getEmployeeById", id);
   }
   @Override
   public List<Employee> findAllEmployees() {
     return sqlSessionTemplate.selectList("com.jdd.dao.EmployeeDao.findAllEmployees");
   }
 }

　　5、同样现在也可以在service类里直接注入 employeeDao使用了。

　　注：这里basedao的注入比较灵活，也可以注入 SqlSessionFactory， 然后再setter方法里创建 SqlSessionTemplate，如下：

 package com.jdd.dao;
 import org.apache.ibatis.session.SqlSessionFactory;
 import org.mybatis.spring.SqlSessionTemplate;
 import javax.annotation.Resource;
 public abstract class BaseDao {
   public SqlSessionTemplate sqlSessionTemplate;
   @Resource
   public void setSqlSessionFactory(SqlSessionFactory sqlSessionFactory) {
     sqlSessionTemplate = new SqlSessionTemplate(sqlSessionFactory);
   }
 }

　　其实不管是采用 继承SqlSessionDaoSupport类， 注入 sqlSessionFactory的方式， 还是直接注入 SqlSessionTemplate 的方式， 本质上是一样的。

　　如果你采用 注入 sqlSessionFactory的方式， 它在底层也是通过sqlSessionFactory 来创建 SqlSessionTemplate ，然后通过其api来操作。

　　不信给你们看下 SqlSessionDaoSupport 的源码：

 //
 // Source code recreated from a .class file by IntelliJ IDEA
 // (powered by Fernflower decompiler)
 //
 package org.mybatis.spring.support;
 import org.apache.ibatis.session.SqlSession;
 import org.apache.ibatis.session.SqlSessionFactory;
 import org.mybatis.spring.SqlSessionTemplate;
 import org.springframework.dao.support.DaoSupport;
 import org.springframework.util.Assert;
 public abstract class SqlSessionDaoSupport extends DaoSupport {
   private SqlSession sqlSession;
   private boolean externalSqlSession;
   public SqlSessionDaoSupport() {
   }
   public void setSqlSessionFactory(SqlSessionFactory sqlSessionFactory) {
     if (!this.externalSqlSession) {
       this.sqlSession = new SqlSessionTemplate(sqlSessionFactory);
     }
   }
   public void setSqlSessionTemplate(SqlSessionTemplate sqlSessionTemplate) {
     this.sqlSession = sqlSessionTemplate;
     this.externalSqlSession = true;
   }
   public SqlSession getSqlSession() {
     return this.sqlSession;
   }
   protected void checkDaoConfig() {
     Assert.notNull(this.sqlSession, "Property 'sqlSessionFactory' or 'sqlSessionTemplate' are required");
   }
 }

　　同样 SqlSessionTemplate 继承了 SqlSession 接口， 因此不管操作哪个效果都一样

 //
  // Source code recreated from a .class file by IntelliJ IDEA
  // (powered by Fernflower decompiler)
  //
  package org.mybatis.spring;
  import java.lang.reflect.InvocationHandler;
  import java.lang.reflect.Method;
 import java.lang.reflect.Proxy;
 import java.sql.Connection;
 import java.util.List;
 import java.util.Map;
 import org.apache.ibatis.exceptions.PersistenceException;
 import org.apache.ibatis.executor.BatchResult;
 import org.apache.ibatis.reflection.ExceptionUtil;
 import org.apache.ibatis.session.Configuration;
 import org.apache.ibatis.session.ExecutorType;
 import org.apache.ibatis.session.ResultHandler;
 import org.apache.ibatis.session.RowBounds;
 import org.apache.ibatis.session.SqlSession;
 import org.apache.ibatis.session.SqlSessionFactory;
 import org.springframework.dao.support.PersistenceExceptionTranslator;
 import org.springframework.util.Assert;
 public class SqlSessionTemplate implements SqlSession {
   private final SqlSessionFactory sqlSessionFactory;
   private final ExecutorType executorType;
   private final SqlSession sqlSessionProxy;
   private final PersistenceExceptionTranslator exceptionTranslator;
   public SqlSessionTemplate(SqlSessionFactory sqlSessionFactory) {
     this(sqlSessionFactory, sqlSessionFactory.getConfiguration().getDefaultExecutorType());
   }
   public SqlSessionTemplate(SqlSessionFactory sqlSessionFactory, ExecutorType executorType) {
     this(sqlSessionFactory, executorType, new MyBatisExceptionTranslator(sqlSessionFactory.getConfiguration().getEnvironment().getDataSource(), true));
   }
   public SqlSessionTemplate(SqlSessionFactory sqlSessionFactory, ExecutorType executorType, PersistenceExceptionTranslator exceptionTranslator) {
     Assert.notNull(sqlSessionFactory, "Property 'sqlSessionFactory' is required");
     Assert.notNull(executorType, "Property 'executorType' is required");
     this.sqlSessionFactory = sqlSessionFactory;
     this.executorType = executorType;
     this.exceptionTranslator = exceptionTranslator;
     this.sqlSessionProxy = (SqlSession)Proxy.newProxyInstance(SqlSessionFactory.class.getClassLoader(), new Class[]{SqlSession.class}, new SqlSessionTemplate.SqlSessionInterceptor());
   }
   public SqlSessionFactory getSqlSessionFactory() {
     return this.sqlSessionFactory;
   }
   public ExecutorType getExecutorType() {
     return this.executorType;
   }
   public PersistenceExceptionTranslator getPersistenceExceptionTranslator() {
     return this.exceptionTranslator;
   }
   public <T> T selectOne(String statement) {
     return this.sqlSessionProxy.selectOne(statement);
   }
   public <T> T selectOne(String statement, Object parameter) {
     return this.sqlSessionProxy.selectOne(statement, parameter);
   }
   public <K, V> Map<K, V> selectMap(String statement, String mapKey) {
     return this.sqlSessionProxy.selectMap(statement, mapKey);
   }
   public <K, V> Map<K, V> selectMap(String statement, Object parameter, String mapKey) {
     return this.sqlSessionProxy.selectMap(statement, parameter, mapKey);
   }
   public <K, V> Map<K, V> selectMap(String statement, Object parameter, String mapKey, RowBounds rowBounds) {
     return this.sqlSessionProxy.selectMap(statement, parameter, mapKey, rowBounds);
   }
   public <E> List<E> selectList(String statement) {
     return this.sqlSessionProxy.selectList(statement);
   }
   public <E> List<E> selectList(String statement, Object parameter) {
     return this.sqlSessionProxy.selectList(statement, parameter);
   }
   public <E> List<E> selectList(String statement, Object parameter, RowBounds rowBounds) {
     return this.sqlSessionProxy.selectList(statement, parameter, rowBounds);
   }
   public void select(String statement, ResultHandler handler) {
     this.sqlSessionProxy.select(statement, handler);
   }
   public void select(String statement, Object parameter, ResultHandler handler) {
     this.sqlSessionProxy.select(statement, parameter, handler);
   }
   public void select(String statement, Object parameter, RowBounds rowBounds, ResultHandler handler) {
     this.sqlSessionProxy.select(statement, parameter, rowBounds, handler);
   }
   public int insert(String statement) {
     return this.sqlSessionProxy.insert(statement);
   }
   public int insert(String statement, Object parameter) {
     return this.sqlSessionProxy.insert(statement, parameter);
   }
   public int update(String statement) {
     return this.sqlSessionProxy.update(statement);
   }
   public int update(String statement, Object parameter) {
     return this.sqlSessionProxy.update(statement, parameter);
   }
   public int delete(String statement) {
     return this.sqlSessionProxy.delete(statement);
   }
   public int delete(String statement, Object parameter) {
     return this.sqlSessionProxy.delete(statement, parameter);
   }
   public <T> T getMapper(Class<T> type) {
     return this.getConfiguration().getMapper(type, this);
   }
   public void commit() {
     throw new UnsupportedOperationException("Manual commit is not allowed over a Spring managed SqlSession");
   }
   public void commit(boolean force) {
     throw new UnsupportedOperationException("Manual commit is not allowed over a Spring managed SqlSession");
   }
   public void rollback() {
     throw new UnsupportedOperationException("Manual rollback is not allowed over a Spring managed SqlSession");
   }
   public void rollback(boolean force) {
     throw new UnsupportedOperationException("Manual rollback is not allowed over a Spring managed SqlSession");
   }
   public void close() {
     throw new UnsupportedOperationException("Manual close is not allowed over a Spring managed SqlSession");
   }
   public void clearCache() {
     this.sqlSessionProxy.clearCache();
   }
   public Configuration getConfiguration() {
     return this.sqlSessionFactory.getConfiguration();
   }
   public Connection getConnection() {
     return this.sqlSessionProxy.getConnection();
   }
   public List<BatchResult> flushStatements() {
     return this.sqlSessionProxy.flushStatements();
   }
   private class SqlSessionInterceptor implements InvocationHandler {
     private SqlSessionInterceptor() {
     }
     public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
       SqlSession sqlSession = SqlSessionUtils.getSqlSession(SqlSessionTemplate.this.sqlSessionFactory, SqlSessionTemplate.this.executorType, SqlSessionTemplate.this.exceptionTranslator);
       Object unwrapped;
       try {
         Object result = method.invoke(sqlSession, args);
         if (!SqlSessionUtils.isSqlSessionTransactional(sqlSession, SqlSessionTemplate.this.sqlSessionFactory)) {
           sqlSession.commit(true);
         }
         unwrapped = result;
       } catch (Throwable var) {
         unwrapped = ExceptionUtil.unwrapThrowable(var);
         if (SqlSessionTemplate.this.exceptionTranslator != null && unwrapped instanceof PersistenceException) {
           SqlSessionUtils.closeSqlSession(sqlSession, SqlSessionTemplate.this.sqlSessionFactory);
           sqlSession = null;
           Throwable translated = SqlSessionTemplate.this.exceptionTranslator.translateExceptionIfPossible((PersistenceException)unwrapped);
           if (translated != null) {
             unwrapped = translated;
           }
         }
         throw (Throwable)unwrapped;
       } finally {
         if (sqlSession != null) {
           SqlSessionUtils.closeSqlSession(sqlSession, SqlSessionTemplate.this.sqlSessionFactory);
         }
       }
       return unwrapped;
     }
   }
 }

总结

以上所述是小编给大家介绍的spring 整合 mybatis 中数据源的几种配置方式，希望对大家有所帮助，如果大家有任何疑问欢迎给我留言，小编会及时回复大家的！