现在开发流行MVC模式，structs在C（控制器）中使用；hibernate在M（模型）中被使用；至于 spring ，最大的作用在于，structs、hibernate的对象，由于在各个层之间相互调用，自己维护不够效率、会产生疏漏，所以，spring 提供一个容器（IOC），structs、hibernate的对象交由spring管理即可。
另外，spring还有一个作用，AOP是切面编程，就是不同地方的相同代码，spring提取出来，进行统一的使用。
总之，spring就是把开发中共性的问题，抽取出来，统一的调用。
MVC中的V（视图），可以用JSP、structs、ExtJs、JQuery等框架或技术实现。
Structs+Spring+Hibernate，这是很经典的一个搭配，它的开发流程也比较程式化，下面以用户注册为例。
注册页面代码：
<%@page contentType="text/html;charset=GBK"%>
<html> <head><title>Spring、Struts和Hibernate整合之用户注册</title></head> <body>${msg} <form name="user" action="/myHibernate/regedit.do" method="post"> 用户名 <input type="text" name="username" value="${user.username}"/><br> 密 码 <input type="password" name="password" value="${user.password}"/><br> <input type="submit" name="method" value="提交"/> </form> </body> </html>
实体Bean类：
// 定义id private String id = null; //定义用户名 private String username = null; //定义密码 private String password = null; //设定id
public void setId(String id) { this.id = id;
} //获取id public String getId() { return this.id; } //设定用户名 public void setUsername (String username) { this.username = username; } //获取用户名 public String getUsername () { return this.username; } //设定密码 public void setPassword (String password) { this.password = password; } //获取密码 public String getPassword () { return this.password; }
}
对应的映射文件User.hbm.xml:
<?xml version="1.0"?><!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd"><hibernate-mapping package="com.myHibernate.bean"> <class name="User" table="user"> <!--定义id--> <id name="id" column="id"> <generator class="native"/> </id> <!--定义用户名--> <property name="username"/> <!--定义密码--> <property name="password"/> </class></hibernate-mapping>
用户DAO接口：
package com.myHibernate.dao;import com.myHibernate.bean.User;public interface UserDAO { //查询用户 public abstract User queryUser(String name); //新增用户 public abstract void insertUser(User user); //修改用户 public abstract void updateUser(User user); //删除用户 public abstract void deleteUser(User user);}
用户DAO接口实现类：
package com.myHibernate.dao.impl;import org.hibernate.SessionFactory;import org.springframework.orm.hibernate3.support.HibernateDaoSupport;import com.myHibernate.bean.User;import com.myHibernate.dao.UserDAO;public class UserDAOImpl extends HibernateDaoSupport implements UserDAO{ private SessionFactory sessionFactory; private String hql = "from User u where u.username = ?"; //查询用户 public User queryUser(String name) { User user = null; //如果查询结果为空 if (this.getHibernateTemplate().find(hql, name) == null ) { user = null; } else { //不为空时，取第一笔 user = (User)this.getHibernateTemplate().find(hql, name).get(0); } return user; } //新增用户 public void insertUser(User user) { this.getHibernateTemplate().save(user); } //修改用户 public void updateUser(User user) { this.getHibernateTemplate().update(user); } //删除用户 public void deleteUser(User user) { this.getHibernateTemplate().delete(user); }}
注册的业务逻辑接口：
package com.myHibernate.domain;import com.myHibernate.bean.User;public interface Regedit { //保存用户 public abstract void saveUser(User user); //修改用户 public abstract void updateUser(User user); //删除用户 public abstract void deleteUser(User user); //获取是否保存成功的消息 public abstract String getMsg();}
注册的业务逻辑实现：
package com.myHibernate.domain.impl;import com.myHibernate.bean.User;import com.myHibernate.dao.UserDAO;import com.myHibernate.domain.Regedit;public class RegeditImpl implements Regedit{ private String msg; private UserDAO userDao; //保存用户 public void saveUser(User user) { userDao.insertUser(user); msg = "保存成功"; } //修改用户 public void updateUser(User user) { userDao.updateUser(user); } //删除用户 public void deleteUser(User user) { userDao.deleteUser(user); } //获取是否保存成功的消息 public String getMsg() { return msg; } /** * @返回userDao */ public UserDAO getUserDao() { return userDao; } /** * @注入userDao */ public void setUserDao(UserDAO userDao) { this.userDao = userDao; }}
用户注册控制器类：
package com.myHibernate.action;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;//导入struts包import org.apache.struts.action.Action;import org.apache.struts.action.ActionForm;import org.apache.struts.action.ActionForward;import org.apache.struts.action.ActionMapping;import com.myHibernate.bean.User;import com.myHibernate.domain.Regedit;//继承action public class RegeditAction extends Action { //定义接口Regedit private Regedit regedit; //获取值 public Regedit getRegedit () { return regedit; } //依赖注入值 public void setRegedit (Regedit regedit) { this.regedit = regedit; } public ActionForward execute(ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response) throws Exception { //获取用户提交的信息 User user = (User)form; //保存用户提交的信息 getRegedit().saveUser(user); //将用户提交的信息和是否保存成功的信息存放在request中 request.setAttribute("user", user); request.setAttribute("msg", regedit.getMsg()); //返回页面 return mapping.findForward("regedit"); }}
下面是配置文件方面，首先是Hibernate的配置文件hibernate.cfg.xml，定义了访问数据库所需要的一些值：
<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE hibernate-configuration PUBLIC "-//Hibernate/Hibernate Configuration DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd"><hibernate-configuration> <session-factory> <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property> <property name="hibernate.connection.url">jdbc:mysql://localhost/myHibernate</property> <property name="hibernate.connection.username">root</property> <property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property> <property name="show_sql">true</property> <mapping resource="com/myHibernate/bean/User.hbm.xml"/> </session-factory></hibernate-configuration>
然后是Spring的配置文件spring-config.xml：
<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd"><beans> <!--定义数据源--> <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close"> <!--设定驱动--> <property name="driverClassName"> <value>com.mysql.jdbc.Driver</value> </property> <!--设定url--> <property name="url"> <value>jdbc:mysql://localhost/myHibernate</value> </property> <!--设定用户名--> <property name="username"> <value>root</value> </property> </bean> <!--通过org.springframework.orm.hibernate3.LocalSessionFactoryBean建立联系--> <bean id="sessionFactory" class="org.springframework.orm.hibernate3.LocalSessionFactoryBean"> <property name="dataSource"> <ref local="dataSource" /> </property> <!--定义要使用的映射文件--> <property name="mappingResources"> <list> <value>commyHibernateeanUser.hbm.xml</value> </list> </property> <!--定义要使用的方言和是否显示sql--> <property name="hibernateProperties"> <props> <prop key="hibernate.dialect">org.hibernate.dialect.MySQLDialect</prop> <prop key="hibernate.show_sql">true</prop> </props> </property> </bean> <!--这里添加对事务处理的支持，当然也可以不用--> <bean id="transactionManager" class="org.springframework.orm.hibernate3.HibernateTransactionManager"> <property name="sessionFactory"> <ref local="sessionFactory" /> </property> </bean> <!--表示要将下面定义的userDao置于事务处理之下--> <bean id="userDaoProxy" class="org.springframework.transaction.interceptor.TransactionProxyFactoryBean"> <property name="transactionManager"> <ref bean="transactionManager" /> </property> <!--要代理userDao--> <property name="target"> <ref local="userDao" /> </property> <!--定义不同情况下，事务处理的方式--> <property name="transactionAttributes"> <props> <prop key="create*">PROPAGATION_REQUIRED</prop> <prop key="update*">PROPAGATION_REQUIRED</prop> <prop key="delete*">PROPAGATION_REQUIRED</prop> <prop key="query*">PROPAGATION_REQUIRED,readOnly</prop> </props> </property> </bean> <!--定义userDao--> <bean id="userDao" class="com.myHibernate.dao.impl.UserDAOImpl"> <property name="sessionFactory"> <ref local="sessionFactory" /> </property> </bean> <!--定义regedit，将UserDAO进行注入--> <bean id="regedit" class="com.myHibernate.domain.impl.RegeditImpl"> <property name="userDao"> <ref local="userDao" /> </property> </bean> <!--定义login，将UserDAO进行注入--> <bean id="login" class="com.myHibernate.domain.impl.LoginImpl"> <property name="userDao"> <ref local="userDao" /> </property> </bean> <!--定义和Struts相应的映射，将regedit进行注入--> <bean name="/regedit" class="com.myHibernate.action.RegeditAction"> <property name="regedit"> <ref bean="regedit"/> </property> </bean> <!--定义和Struts相应的映射，将login进行注入--> <bean name="/login" class="com.myHibernate.action.LoginAction"> <property name="login"> <ref bean="login"/> </property> </bean></beans>
然后是Struts的配置文件struts-config.xml:
<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE struts-config PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 1.2//EN" "http://jakarta.apache.org/struts/dtds/struts-config_1_2.dtd"><struts-config><!--定义formbean--><form-beans><form-bean name="user" type="com.myHibernate.bean.User"/></form-beans> <action-mappings> <!--定义和SPring配置文件相同的路径--> <action path="/regedit" type="org.springframework.web.struts.DelegatingActionProxy" name="user"> <forward name="regedit" path="/jsp/regedit.jsp"/> </action> <!--定义初次访问时的路径--> <action path="/input" type="org.apache.struts.actions.ForwardAction" parameter="/jsp/regedit.jsp"/> <!--定义和SPring配置文件相同的路径--> <action path="/login" type="org.springframework.web.struts.DelegatingActionProxy" name="user"> <forward name="login" path="/jsp/login.jsp"/> </action> <!--定义初次访问时的路径--> <action path="/loginTemp" type="org.apache.struts.actions.ForwardAction" parameter="/jsp/login.jsp"/> </action-mappings> <!--注册ContextLoaderPlugIn插件--> <plug-in className="org.springframework.web.struts.ContextLoaderPlugIn"> <set-property property="contextConfigLocation" value="/WEB-INF/spring-config.xml" /> </plug-in></struts-config>
最后是Web应用程序配置文件web.xml:
<?xml version="1.0" encoding="UTF-8"?><web-app version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"> <servlet> <servlet-name>actionServlet</servlet-name> <servlet-class>org.apache.struts.action.ActionServlet</servlet-class> <!--初始参数--> <init-param> <param-name>config</param-name> <param-value>/WEB-INF/struts-config.xml</param-value> </init-param> <load-on-startup>1</load-on-startup></servlet> <!--处理所有后缀为do的请求--> <servlet-mapping> <servlet-name>actionServlet</servlet-name> <url-pattern>*.do</url-pattern> </servlet-mapping></web-app>
可以看到，MVC的三层架构思路很清晰，但缺点也很明显，配置文件太过于冗杂，CRUD代码随处冗余，不够简约，下一篇文章中我们将见识到一个解决这个问题的优秀框架—SpringSide。