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  • spring-mybatis+spring整合

    整合之前回忆一下spring和mybatis分别做了什么:

    spring 通过注解/xml配置,实现AOP和DI

    DI: 接口实现类中, 将接口私有化,从容器中读取,而不是new一个

    UserDao userDao=new UserDaoImpl()
    //改写成
    private UserDao userDao
    

      

    IoC:获取类时,从容器中获取

    UserDao userDao = new UserDaoImpl();
    //改成
    UserDao userDao = applicationConfig.getBean("userDao");
    

      

    AOP:将一些常用的操作,编写成切面,插入到程序中,通过监听实现

    Before
    After
    ...
    

     

    mybatis 通过config.xml mapper.xml ,实体类,serviceImpl,来映射数据库数据,并且通过对实体类的进行serviceImpl的操作,来调用mapper内容,对数据库数据进行操作

    class People{
      private String name;
      ....getting/setting/toString;  
    }
    class PeopleService{
        private People people;
      void addPeople(){
    }
    }
    class PeopleServiceImpl{
      private People people;
      void addPeople(){
    }
    ....
    }
    Peoplemapper.xml
    insert xxxxxx
    
    config.xml
    Peoplemapper.xml
    jdbc
    ....
    

      

    两者整合起来可以做什么,我还不是很清楚。。。

    ——————————————————————————————————————

    整合

    一/,导入mybatis-spring的包

    		<dependency>
    			<groupId>org.mybatis</groupId>
    			<artifactId>mybatis-spring</artifactId>
    			<version>2.0.1</version>
    		</dependency>
    

      

    二/ 编辑applicationContent.xml,加入sqlSessionFactory

    	<bean id="sqlSessionFactory" class = "org.mybatis.spring.SqlSessionFactoryBean">
    		<property name="dataSource" ref = "dataSource"/>
    		<property name="configLocation" value="classpath:mybatis-config.xml"/>
    	</bean>
    

     mybatis-config.xml中environment部分可以注释掉了

    <environments default="mysql">
             <!-- 配置id为mysql的数据库环境 -->
    		<environment id = "mysql">
    		<transactionManager type="JDBC"/>
    			<dataSource type = "POOLED">
    			<property name = "driver" value = "${jdbc.driver}"/>
    			<property name = "url" value = "${jdbc.url}"/>
    			<property name = "username" value = "${jdbc.username}"/>
    			<property name = "password" value = "${jdbc.password}"/>
    		</dataSource>
    		</environment>
    	</environments>
    

      

    三/ 与mybatis方法用的差不多。

      原理:创建DAO和DAOIMPL,在daoImpl中注入sqlSessionFactory,创建sqlSession来操作。

      提供:mybatis-spring包提供了SqlSessionTemplate和SqlSessionDaoSupport来实现。

      具体内容:

      1. SqlSessionTemplate:负责当前SqlSession和当前Spring事务时相关的,并管理SqlSession(关闭,提交,回滚)

      2. SqlSessionDaoSupport作为DAO的基类来使用,提供方法 getSqlSession()

    四/代码实现

      Customer,CustomerDao,customerMapper.xml,mybatis-config.xml没变化。

    CustomerDaoImpl修改如下

    public class CustomerImpl
        extends SqlSessionDaoSupport
        implements CustomerDao{
        public Customer findCustomerById(Integer id){
            return this.getSqlSession().selectOne("com.itheima.mapper.CustomerMapper.findCustomerById",id);
        }
    }
    

      

    以上代码需要SqlSessionFactory来创建sqlSession,这里通过注入来实现,修改applicationContext.xml

    	<bean id = "customerDao" class = "com.itheima.dao.impl.CustomerImpl">
    		<property name="sqlSessionFactory" ref ="sqlSessionFactory"/>
    	</bean>
    

     

    以上代码将sqlSessionFactory注入到CustomerImpl中,这里的注入sqlSessionFactory是父类SqlSessionDaoSupport的一个私有属性。

      public void setSqlSessionFactory(SqlSessionFactory sqlSessionFactory) {
        if (this.sqlSessionTemplate == null || sqlSessionFactory != this.sqlSessionTemplate.getSqlSessionFactory()) {
          this.sqlSessionTemplate = createSqlSessionTemplate(sqlSessionFactory);
        }
      }
    

      

     (property元素用于调用bean示例中的setter方法,完成属性赋值)

    用xml方式整合

    原则

    去除dao和daoImpl的class

    在applicationContext.xml中增加bean

    	<bean id="customerMapper" class="org.mybatis.spring.mapper.MapperFactoryBean">
    		<property name="mapperInterface" value="com.itheima.mapper.CustomerMapper" />
    		<property name="sqlSessionFactory" ref="sqlSessionFactory" />
    	</bean>
    	<!--可以自行给bean加property?-->
    	    <bean id="sqlSessionFactory" 
                class="org.mybatis.spring.SqlSessionFactoryBean">
             <!--注入数据源 -->
             <property name="dataSource" ref="dataSource" />
             <!--指定核心配置文件位置 -->
       		<property name="configLocation" value="classpath:mybatis-config.xml"/>
       </bean>
    

      

    在mapper.xml同路径下新增mapper.java

    package com.itheima.mapper;
    
    import com.itheima.po.Customer;;
    
    public interface CustomerMapper {
        public Customer findCustomerById(Integer id);
    }
    

      

    public class DaoTest {
        @Test
        public void findCustometByIdMapperTest(){
            ApplicationContext act = new
                    ClassPathXmlApplicationContext("applicationContext.xml");
            CustomerMapper customerMapper = act.getBean(CustomerMapper.class);
            Customer customer = customerMapper.findCustomerById(1);
            System.out.print(customer);
            }
    }
    

      

    基于MapperScannerConfigurer的整合

    不需要编写DaoImpl实现类,不需要添加DaoImpl的bean。

    增加一个扫描mapper的路径,直接读

    	<bean class ="org.mybatis.spring.mapper.MapperScannerConfigurer">
    		<property name="basePackage" value="com.itheima.mapper"/>
    	</bean>
    	   <bean id="sqlSessionFactory"
                class="org.mybatis.spring.SqlSessionFactoryBean">
    
             <property name="dataSource" ref="dataSource" />
    
       		<property name="configLocation" value="classpath:mybatis-config.xml"/>
       </bean>
    

      

    用mapperScannerConfigurer+事务+service处理数据(比用mapper多一层,用service做一些业务处理)

    这边增删改都要用事务(具体是数据库的事务的ACID原则,不多讲)

    @Service
    @Transactional
    public class CustomerServiceImpl implements CustomerService {
    	//注解注入CustomerMapper
    	@Autowired
    	private CustomerMapper customerMapper;
    	//添加客户
    	@Override
    	public void addCustomer(Customer customer) {
    		this.customerMapper.addCustomer(customer);
    		int i=1/0; //模拟添加操作后系统突然出现的异常问题
    	}
    }
    

      

    mapper中增加对应的方法(略)

    applicationContext中增加扫描包

    <context:component-scan base-package="com.itheima.service" />
    

      

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  • 原文地址:https://www.cnblogs.com/zhizhiyin/p/11038668.html
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