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详解Spring MVC事务配置

2024-07-13 10:06:19
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要了解事务配置的所有方法,请看一下《Spring事务配置的5种方法》

本文介绍两种配置方法:

 一、XML,使用tx标签配置拦截器实现事务

二、Annotation方式

以下所使用环境为Spring4.0.3、Hibernate4.3.5

 一、 XML,使用tx标签配置拦截器实现事务

Entity类User.java,持久化类,对应数据库表user

package com.lei.demo.entity;import javax.persistence.*;@Entity(name="users")public class Users {    public Users(){    super();  }    @Id  @GeneratedValue(strategy=GenerationType.AUTO)  @Column(name="id")  private Integer id;    @Column(name="user_name",length=32)  private String user_name;    @Column(name="age")  private Integer age;    @Column(name="nice_name",length=32)  private String nice_name;    //属性实现......}

UserDAO.javar,表user的一些操作,其中属性sessionFactory应该由Spring注入,如下:

package com.lei.demo.dao;import java.util.List;import javax.annotation.Resource;import org.hibernate.Query;import org.hibernate.Session;import org.hibernate.SessionFactory;import org.springframework.stereotype.Repository;import com.lei.demo.entity.Users;public class UsersDAO {  private SessionFactory sessionFactory;  public void setSessionFactory(SessionFactory sessionFactory) {    this.sessionFactory = sessionFactory;  }  public SessionFactory getSessionFactory() {    return sessionFactory;  }  public List<Users> getAllUser(){    String hsql="from users";    Session session = sessionFactory.getCurrentSession();    Query query = session.createQuery(hsql);        return query.list();  }}

UserService.java,业务实现类,如下

package com.lei.demo.service;import javax.annotation.Resource;import org.springframework.stereotype.Service;import org.springframework.transaction.annotation.Isolation;import org.springframework.transaction.annotation.Propagation;import org.springframework.transaction.annotation.Transactional;import com.lei.demo.dao.*;public class UserService {  private UsersDAO userDao;    public int userCount(){    return userDao.getAllUser().size();  }  public UsersDAO getUserDao() {    return userDao;  }  public void setUserDao(UsersDAO userDao) {    this.userDao = userDao;  }}

首先看一下xml配置,spring-hibernate.xml如下:

<?xml version="1.0" encoding="UTF-8"?><beans xmlns="http://www.springframework.org/schema/beans"  xmlns:context="http://www.springframework.org/schema/context"  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"  xmlns:tx="http://www.springframework.org/schema/tx"  xmlns:aop="http://www.springframework.org/schema/aop"  xsi:schemaLocation="    http://www.springframework.org/schema/beans       http://www.springframework.org/schema/beans/spring-beans-4.0.xsd    http://www.springframework.org/schema/context    http://www.springframework.org/schema/context/spring-context-4.0.xsd    http://www.springframework.org/schema/aop    http://www.springframework.org/schema/aop/spring-aop-4.0.xsd    http://www.springframework.org/schema/tx    http://www.springframework.org/schema/tx/spring-tx-4.0.xsd    ">  <!-- Hibernate4 -->  <!-- 加载资源文件 其中包含变量信息,必须在Spring配置文件的最前面加载,即第一个加载-->  <context:property-placeholder location="classpath:persistence-mysql.properties" />    <bean id="sessionFactory"     class="org.springframework.orm.hibernate4.LocalSessionFactoryBean">    <property name="dataSource" ref="dataSource" />    <property name="packagesToScan">      <list>        <!-- 可以加多个包 -->        <value>com.lei.demo.entity</value>      </list>    </property>    <property name="hibernateProperties">      <props>        <prop key="hibernate.hbm2ddl.auto">${hibernate.hbm2ddl.auto}</prop>        <prop key="hibernate.dialect">${hibernate.dialect}</prop>        <prop key="hibernate.show_sql">${hibernate.show_sql}</prop>        <!-- <prop key="hibernate.current_session_context_class">thread</prop> -->       </props>    </property>  </bean>    <!-- 数据库映射 -->  <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">   <property name="driverClassName" value="${jdbc.driverClassName}" />   <property name="url" value="${jdbc.url}" />   <property name="username" value="${jdbc.user}" />   <property name="password" value="${jdbc.pass}" />  </bean>    <!-- 配置Hibernate事务管理器 -->  <bean id="transactionManager"    class="org.springframework.orm.hibernate4.HibernateTransactionManager">   <property name="sessionFactory" ref="sessionFactory" />  </bean>    <!-- 配置事务异常封装 -->  <bean id="persistenceExceptionTranslationPostProcessor"     class="org.springframework.dao.annotation.PersistenceExceptionTranslationPostProcessor" />    <!-- 声明式容器事务管理 ,transaction-manager指定事务管理器为transactionManager -->  <tx:advice id="txAdvice" transaction-manager="transactionManager">    <tx:attributes>      <tx:method name="add*" propagation="REQUIRED" />      <tx:method name="get*" propagation="REQUIRED" />      <tx:method name="*" read-only="true" />    </tx:attributes>  </tx:advice>    <aop:config expose-proxy="true">    <!-- 只对业务逻辑层实施事务 -->    <aop:pointcut id="txPointcut" expression="execution(* com.lei.demo.service..*.*(..))" />    <!-- Advisor定义,切入点和通知分别为txPointcut、txAdvice -->    <aop:advisor pointcut-ref="txPointcut" advice-ref="txAdvice"/>  </aop:config>  </beans>

其中主要配置中是tx:advice和aop:config两个配置节,以Spring AOP的方式实现事务管理。

tx:advice配置了事务的管理者是transactionManager,同时tx:method也规定了如果方法名匹配“add*”和“get*”方法时使用事务,propagation是设定事务的传播级别。除了“add*”和“get*”方法,其他的方法的事务是只读的(典型地,对于只执行查询的事务你会将该属性设为true,如果出现了更新、插入或是删除语句时只读事务就会失败)

aop:config指定了一个aop:pointcut去引用上边的advice。

这样就通过AOP的拦截机制实现了事务,当然你还要用Spring的方式自己配置UserDAO和UserService。

二、Annotation方式

第一步,首先看一下web.xml,如下:

<?xml version="1.0" encoding="UTF-8"?><web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"   xmlns="http://java.sun.com/xml/ns/javaee"   xmlns:web="http://java.sun.com/xml/ns/javaee"   xsi:schemaLocation="http://java.sun.com/xml/ns/javaee     http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"     id="WebApp_ID" version="3.0"> <display-name>Archetype Created Web Application</display-name> <context-param>  <param-name>contextConfigLocation</param-name>  <param-value>classpath:/spring-*.xml</param-value> </context-param> <listener>  <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class> </listener> <servlet>  <servlet-name>lei-dispatcher</servlet-name>  <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>  <init-param>   <param-name>contextConfigLocation</param-name>   <param-value>classpath:/lei-dispatcher-servlet.xml</param-value>  </init-param>  <load-on-startup>1</load-on-startup> </servlet> <servlet-mapping>  <servlet-name>lei-dispatcher</servlet-name>  <url-pattern>/</url-pattern> </servlet-mapping></web-app>

第二步,spring-hibernate配置,见以下spring-hibernate.xml配置

<?xml version="1.0" encoding="UTF-8"?><beans xmlns="http://www.springframework.org/schema/beans"  xmlns:context="http://www.springframework.org/schema/context"  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"  xmlns:tx="http://www.springframework.org/schema/tx"  xmlns:aop="http://www.springframework.org/schema/aop"  xsi:schemaLocation="    http://www.springframework.org/schema/beans       http://www.springframework.org/schema/beans/spring-beans-4.0.xsd    http://www.springframework.org/schema/context    http://www.springframework.org/schema/context/spring-context-4.0.xsd    http://www.springframework.org/schema/aop    http://www.springframework.org/schema/aop/spring-aop-4.0.xsd    http://www.springframework.org/schema/tx    http://www.springframework.org/schema/tx/spring-tx-4.0.xsd    ">  <!-- Hibernate4 -->  <!-- 加载资源文件 其中包含变量信息,必须在Spring配置文件的最前面加载,即第一个加载-->  <context:property-placeholder location="classpath:persistence-mysql.properties" />    <bean id="sessionFactory"     class="org.springframework.orm.hibernate4.LocalSessionFactoryBean">    <property name="dataSource" ref="dataSource" />    <property name="packagesToScan">      <list>        <!-- 可以加多个包 -->        <value>com.lei.demo.entity</value>      </list>    </property>    <property name="hibernateProperties">      <props>        <prop key="hibernate.hbm2ddl.auto">${hibernate.hbm2ddl.auto}</prop>        <prop key="hibernate.dialect">${hibernate.dialect}</prop>        <prop key="hibernate.show_sql">${hibernate.show_sql}</prop>        <!-- <prop key="hibernate.current_session_context_class">thread</prop> -->       </props>    </property>  </bean>    <!-- 数据库映射 -->  <!-- class="org.apache.tomcat.dbcp.dbcp.BasicDataSource" -->  <!-- class="org.springframework.jdbc.datasource.DriverManagerDataSource" -->  <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">   <property name="driverClassName" value="${jdbc.driverClassName}" />   <property name="url" value="${jdbc.url}" />   <property name="username" value="${jdbc.user}" />   <property name="password" value="${jdbc.pass}" />  </bean>    <!-- 配置Hibernate事务管理器 -->  <bean id="transactionManager"    class="org.springframework.orm.hibernate4.HibernateTransactionManager">   <property name="sessionFactory" ref="sessionFactory" />  </bean>    <!-- 配置事务异常封装 -->  <bean id="persistenceExceptionTranslationPostProcessor"     class="org.springframework.dao.annotation.PersistenceExceptionTranslationPostProcessor" /></beans>

第一节中xml配置事务中需要通过配置tx:advice和aop:config来增加事务的功能。此处采用全注释方法,这两个配置节就不需要了。

 相应的需要在视图解析配置中启用注释,如下lei-dispatcher-servlet.xml

<?xml version="1.0" encoding="UTF-8"?><beans xmlns="http://www.springframework.org/schema/beans"  xmlns:context="http://www.springframework.org/schema/context"  xmlns:mvc="http://www.springframework.org/schema/mvc"  xmlns:p="http://www.springframework.org/schema/p"  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"  xmlns:tx="http://www.springframework.org/schema/tx"  xsi:schemaLocation="    http://www.springframework.org/schema/beans       http://www.springframework.org/schema/beans/spring-beans-3.0.xsd    http://www.springframework.org/schema/context    http://www.springframework.org/schema/context/spring-context-3.0.xsd    http://www.springframework.org/schema/mvc    http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd    http://www.springframework.org/schema/tx    http://www.springframework.org/schema/tx/spring-tx-4.0.xsd    ">      <!-- 启动自动扫描 该包下所有的Bean(@Controller) -->  <context:component-scan base-package="com.lei.demo" />    <!-- 基于注释的事务,当注释中发现@Transactional时,使用id为“transactionManager”的事务管理器 -->  <!-- 如果没有设置transaction-manager的值,则spring以缺省默认的事务管理器来处理事务,默认事务管理器为第一个加载的事务管理器 -->  <tx:annotation-driven transaction-manager="transactionManager"/>    <!-- 定义视图解析器 -->  <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">    <property name="prefix">      <value>/WEB-INF/user/</value>    </property>    <property name="suffix">      <value>.jsp</value>    </property>  </bean>  </beans>

UserDAO如下

package com.lei.demo.dao;import java.util.List;import javax.annotation.Resource;import org.hibernate.Query;import org.hibernate.Session;import org.hibernate.SessionFactory;import org.springframework.stereotype.Repository;import com.lei.demo.entity.Users;@Repositorypublic class UsersDAO {  @Resource(name="sessionFactory")  private SessionFactory sessionFactory;  public void setSessionFactory(SessionFactory sessionFactory) {    this.sessionFactory = sessionFactory;  }  public SessionFactory getSessionFactory() {    return sessionFactory;  }  public List<Users> getAllUser(){    String hsql="from users";    Session session = sessionFactory.getCurrentSession();    Query query = session.createQuery(hsql);        return query.list();  }}

UserService.java如下

package com.lei.demo.service;import javax.annotation.Resource;import org.springframework.stereotype.Service;import org.springframework.transaction.annotation.Isolation;import org.springframework.transaction.annotation.Propagation;import org.springframework.transaction.annotation.Transactional;import com.lei.demo.dao.*;@Service("userService")public class UserService {  @Resource  private UsersDAO userDao;    @Transactional  public int userCount(){    return userDao.getAllUser().size();  }  public UsersDAO getUserDao() {    return userDao;  }  public void setUserDao(UsersDAO userDao) {    this.userDao = userDao;  }}

这里,方法名userCount上加入@Transactional,说明这个方法要启用事务。如果类名UserService上加入@Transactional,则表明这个类中的所有方法都会启用事务。

如果配有多个transactionManager,例如配置有transactionManager1,和transactionManager2,则可以通过@Transactional(“transactionManager1”),的方式指定使用哪个数据源的事务。

以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持VeVb武林网。


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