SpringMVC+hibernate

今天用到SpringMVC整合hibernate，基于注解方式，由于之前整合SSH是基于配置文件的，今天走了比较多的弯路，整合过程中最重要的是使用Spring管理Hibernate的SessionFactory，下面是整合过程：

1.web.xml配置：

<?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/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">
  <display-name>json_test</display-name>
  <welcome-file-list>
    <welcome-file>index.jsp</welcome-file>
  </welcome-file-list>
  
  <!-- 加载所有的配置文件 -->
  <context-param>
  	<param-name>contextConfigLocation</param-name>
  	<param-value>classpath:spring-common.xml</param-value>
  </context-param>
  
  <!-- 配置Spring监听 -->
  <listener>
  	<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
  </listener>
  
  <!-- 配置SpringMVC -->
  <servlet>
  	<servlet-name>springMVC</servlet-name>
  	<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
  	<init-param>
  		<param-name>contextConfigLocation</param-name>
  		<param-value>classpath:spring-mvc.xml</param-value>
  	</init-param>
  	<load-on-startup>1</load-on-startup>
  </servlet>
  <servlet-mapping>
  	<servlet-name>springMVC</servlet-name>
  	<url-pattern>/</url-pattern>
  </servlet-mapping>
  
  <!-- 配置字符集 -->
  <filter>
  	<filter-name>encodingFilter</filter-name>
  	<filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
  	<init-param>
  		<param-name>encoding</param-name>
  		<param-value>UTF-8</param-value>
  	</init-param>
  	<init-param>
  		<param-name>forceEncoding</param-name>
  		<param-value>true</param-value>
  	</init-param>
  </filter>
  <filter-mapping>
  	<filter-name>encodingFilter</filter-name>
  	<url-pattern>/*</url-pattern>
  </filter-mapping>
  
  <!-- 配置Session -->
  <filter>
  	<filter-name>openSession</filter-name>
  	<filter-class>org.springframework.orm.hibernate4.support.OpenSessionInViewFilter</filter-class>
  </filter>
  <filter-mapping>
  	<filter-name>openSession</filter-name>
  	<url-pattern>/*</url-pattern>
  </filter-mapping>
</web-app>

 2.spring-mvc.xml配置：

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xmlns:context="http://www.springframework.org/schema/context"
	xmlns:mvc="http://www.springframework.org/schema/mvc"
	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-3.2.xsd
	http://www.springframework.org/schema/mvc
	http://www.springframework.org/schema/mvc/spring-mvc-3.2.xsd">
	
	<!-- 注解扫描包 -->
	<context:component-scan base-package="com.freemark" />

	<!-- 开启注解 -->
	<mvc:annotation-driven />
	
	<!-- 静态资源(js/image)的访问 -->
	<mvc:resources location="/js/" mapping="/js/**"/>

	<!-- 定义视图解析器 -->	
	<bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
		<property name="prefix" value="/WEB-INF/views/"></property>
		<property name="suffix" value=".jsp"></property>
	</bean>
</beans>

 3.spring-common.xml配置：

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xmlns:context="http://www.springframework.org/schema/context"
	xmlns:mvc="http://www.springframework.org/schema/mvc"
	xsi:schemaLocation="http://www.springframework.org/schema/beans 
	http://www.springframework.org/schema/beans/spring-beans.xsd">
	
	<!-- 配置数据源 -->
	<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource" >
		<property name="driverClassName" value="com.mysql.jdbc.Driver"></property>
		<property name="url" value="jdbc:mysql:///freeMark"></property>
		<property name="username" value="root"></property>
		<property name="password" value="123456"></property>
	</bean>
	
	<!-- 配置SessionFactory -->
	<bean id="sessionFactory" class="org.springframework.orm.hibernate4.LocalSessionFactoryBean">
		<property name="dataSource" ref="dataSource" />
		<property name="hibernateProperties">
			<props>
				<prop key="hibernate.dialect">org.hibernate.dialect.MySQL5Dialect</prop>
				<prop key="hibernate.hbm2ddl.auto">update</prop>
				<prop key="hibernate.show_sql">true</prop>
				<prop key="hibernate.format_sql">true</prop>
			</props>
		</property>
		<!-- <property name="annotatedClasses">
			<list>
				<value>com.freemark.model.User</value>
			</list>
		</property> -->
		
		<property name="packagesToScan">
			<list> 
				<value>com.freemark.model</value>
			</list>
		</property>
	</bean>
	
	<!-- 配置一个事务管理器 -->
	<bean id="transactionManager" class="org.springframework.orm.hibernate4.HibernateTransactionManager">
		<property name="sessionFactory" ref="sessionFactory"/>
	</bean>
	
	<!-- 配置事务，使用代理的方式 -->
	<bean id="transactionProxy" class="org.springframework.transaction.interceptor.TransactionProxyFactoryBean" abstract="true">  
	    <property name="transactionManager" ref="transactionManager"></property>  
	    <property name="transactionAttributes">  
	        <props>  
	            <prop key="add*">PROPAGATION_REQUIRED,-Exception</prop>  
	            <prop key="modify*">PROPAGATION_REQUIRED,-myException</prop>  
	            <prop key="del*">PROPAGATION_REQUIRED</prop>  
	            <prop key="*">PROPAGATION_REQUIRED</prop>  
	        </props>  
	    </property>  
	</bean> 
</beans>

 4.测试通过使用的是一个User类，一个SessionDao，一个UserDao，一个TestController，User类和TestController这里都不做介绍了，非常简单，SessionDao和UserDao如下：

SessionDao：

package com.freemark.dao;

import javax.annotation.Resource;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import org.springframework.stereotype.Repository;

@Repository
public class SessionDao {

	
	//sessionFactory
	@Autowired
	private SessionFactory sessionFactory;
	
	public Session getSession(){
		Session session= sessionFactory.getCurrentSession();
		return session;
	}
}

 UserDao：

package com.freemark.dao;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import org.springframework.stereotype.Repository;

@Repository
public class UserDao extends SessionDao  {

	
	/*@Autowired
	private TestController testController;*/
	
	public void getUsers(){
		
		System.out.println(getSession().createQuery("from User").list());
	}
}

 测试完毕，可以通过。

今天在整合的过程遇到一个问题：注入到SessionDao中的SessionFactory为null，为了搞定这个，花了一下午的时间，重做了好几次，这里分享一下为什么会出现这个问题：

1）出现这个问题说明配置的DataSource数据源、SessionFactory配置、事务等都是通过的，没有错误

2）在Spring中不要乱是New对象，这里就是因为在TestController中New了一个UserDao而造成的，因为Spring已经接管了UserDao，这里面是因为什么，源码我没有研究过，各位如果遇到这种null错误可以考虑一下

3）使用web配置的过程中注意classpath的指定，有时候不一定可以读取到spring配置文件

4）控制台打印出错误就是好事情，说明还可以解决