Spring MVC 背景介绍_1

Spring  MVC 背景介绍

Spring 框架提供了构建 Web 应用程序的全功能 MVC 模块。使用 Spring 可插入的 MVC 架构,可以选择是使用内置的 Spring Web 框架还是 Struts 这样的 Web 框架。通过策略接口,Spring 框架是高度可配置的,而且包含多种视图技术,例如 JavaServer Pages(JSP)技术、Velocity、Tiles、iText 和 POI。Spring MVC 框架并不知道使用的视图,所以不会强迫您只使用 JSP 技术。Spring MVC 分离了控制器、模型对象、分派器以及处理程序对象的角色,这种分离让它们更容易进行定制。

 

 

常见MVC框架比较

运行性能上:

         Jsp+servlet>struts1>spring mvc>struts2+freemarker>>struts2,ognl,值栈。

开发效率上,基本正好相反。值得强调的是,spring mvc开发效率和struts2不相上下。

 

Struts2的性能低的原因是因为OGNL和值栈造成的。所以,如果你的系统并发量高,可以使用freemaker进行显示,而不是采用OGNL和值栈。这样,在性能上会有相当大得提高。

 

 

基于spring2.5的采用XML配置的spring MVC项目

注:本项目全部基于XML配置。同时,集成了hibernate。采用的是:spring MVC+hibernate+spring的开发架构。

  1. 建立web项目
  2. 导入jar包(spring.jar, spring-webmvc.jar, commons-logging.jar。其他jar包为hibernate相关jar包)

 

  1. 修改web.xml如下:

<?xml version="1.0" encoding="UTF-8"?>

<web-app version="2.5"

    xmlns="http://java.sun.com/xml/ns/javaee"

    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee

    http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">>

    <servlet>

        <servlet-name>dispatcherServlet</servlet-name>

        <servlet-class>

            org.springframework.web.servlet.DispatcherServlet

        </servlet-class>

        <init-param>

            <param-name>contextConfigLocation</param-name>

            <param-value>/WEB-INF/hib-config.xml,/WEB-INF/web-config.xml,/WEB-INF/service-config.xml,/WEB-INF/dao-config.xml</param-value>

        </init-param>

        <load-on-startup>1</load-on-startup>

    </servlet>

    <servlet-mapping>

        <servlet-name>dispatcherServlet</servlet-name>

        <url-pattern>*.do</url-pattern>

    </servlet-mapping>

</web-app>

 

  1. 增加web-config.xml(这里包含spring mvc相关的相关配置)

<?xml version="1.0" encoding="UTF-8"?>

<beans xmlns="http://www.springframework.org/schema/beans"

    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

    xsi:schemaLocation="

http://www.springframework.org/schema/beans

http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">

   

    <!-- Controller方法调用规则定义 -->

    <bean id="paraMethodResolver"

        class="org.springframework.web.servlet.mvc.multiaction.ParameterMethodNameResolver">

        <property name="paramName" value="action"/>

        <property name="defaultMethodName" value="list"/>

    </bean>

 

   <!-- 页面View层基本信息设定 -->

    <bean id="viewResolver"

          class="org.springframework.web.servlet.view.InternalResourceViewResolver">

        <property name="viewClass"

            value="org.springframework.web.servlet.view.JstlView"/>

        <!--<property name="prefix" value="/myjsp/"/>-->

        <property name="suffix" value=".jsp"/>

    </bean>

 

<!-- servlet映射列表,所有控制层Controller的servlet在这里定义 -->

    <bean id="urlMapping"

          class="org.springframework.web.servlet.handler.SimpleUrlHandlerMapping">

        <property name="mappings">

            <props>

                <prop key="user.do">userController</prop>

            </props>

        </property>

    </bean>

 

<bean id="userController" class="com.sxt.action.UserController">

    <property name="userService" ref="userService"></property>

</bean>

</beans>

 

  1. 在WEB-INF下增加service-config.xml(这里包含service层类的相关配置)

<?xml version="1.0" encoding="UTF-8"?>

<beans xmlns="http://www.springframework.org/schema/beans"

    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

    xsi:schemaLocation="

http://www.springframework.org/schema/beans

http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">

 

    <bean id="userService" class="com.sxt.service.UserService">

       <property name="userDao" ref="userDao"></property>

    </bean>

   

</beans>

 

  1. 在WEB-INF下增加hib-config.xml(这里包含spring集成hibernate相关的配置)

<?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:aop="http://www.springframework.org/schema/aop"

    xmlns:tx="http://www.springframework.org/schema/tx"

    xmlns:context="http://www.springframework.org/schema/context"

    xsi:schemaLocation="

http://www.springframework.org/schema/beans

http://www.springframework.org/schema/beans/spring-beans-2.5.xsd

http://www.springframework.org/schema/tx

http://www.springframework.org/schema/tx/spring-tx-2.5.xsd

http://www.springframework.org/schema/aop

http://www.springframework.org/schema/aop/spring-aop-2.5.xsd

  http://www.springframework.org/schema/context  

   http://www.springframework.org/schema/context/spring-context-2.5.xsd

">

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

    <!-- 支持aop注解 -->

    <aop:aspectj-autoproxy />

   

      

    <bean id="dataSource" 

            class="org.apache.commons.dbcp.BasicDataSource"

            <property name="driverClassName" 

                value="com.mysql.jdbc.Driver"

            </property> 

            <property name="url" value="jdbc:mysql://localhost:3306/myhib"></property> 

            <property name="username" value="root"></property> 

            <property name="password" value="123456"></property>

    </bean> 

 

   <bean id="sessionFactory" 

       class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean"

           <property name="dataSource"

               <ref bean="dataSource" /> 

           </property>

           <property name="hibernateProperties"

               <props> 

                  <!-- key的名字前面都要加hibernate. -->

                   <prop key="hibernate.dialect"

                       org.hibernate.dialect.MySQLDialect 

                   </prop> 

                   <prop key="hibernate.show_sql">true</prop>

                   <prop key="hibernate.hbm2ddl.auto">update</prop>

               </props>

           </property>

       <property name="packagesToScan">

           <value>com.sxt.po</value>

       </property>

   </bean> 

 

<bean id="hibernateTemplate" class="org.springframework.orm.hibernate3.HibernateTemplate" >

    <property name="sessionFactory" ref="sessionFactory"></property>

</bean>

 

<!--配置一个JdbcTemplate实例--> 

<bean id="jdbcTemplate"  class="org.springframework.jdbc.core.JdbcTemplate">  

     <property name="dataSource" ref="dataSource"/>  

</bean> 

 

 

<!-- 配置事务管理 -->

<bean id="txManager" class="org.springframework.orm.hibernate3.HibernateTransactionManager" >

    <property name="sessionFactory" ref="sessionFactory"></property>

</bean>

<tx:annotation-driven transaction-manager="txManager" />

<aop:config>

    <aop:pointcut expression="execution(public * com.sxt.service.impl.*.*(..))" id="businessService"/>

    <aop:advisor advice-ref="txAdvice" pointcut-ref="businessService" />

</aop:config>

<tx:advice id="txAdvice" transaction-manager="txManager" >

    <tx:attributes>

       <tx:method name="find*"  read-only="true" propagation="NOT_SUPPORTED"  />

       <!-- get开头的方法不需要在事务中运行 。

       有些情况是没有必要使用事务的,比如获取数据。开启事务本身对性能是有一定的影响的-->

       <tx:method name="*"/>    <!-- 其他方法在实务中运行 -->

    </tx:attributes>

</tx:advice>

 

</beans>

 

  1. 在WEB-INF下增加dao-config.xml(这里包含dao层类的相关配置)

<?xml version="1.0" encoding="UTF-8"?>

<beans xmlns="http://www.springframework.org/schema/beans"

    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

    xsi:schemaLocation="

http://www.springframework.org/schema/beans

http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">

   

    <bean id="userDao" class="com.sxt.dao.UserDao">

      <property name="hibernateTemplate" ref="hibernateTemplate"></property>

    </bean>

</beans>

 

  1. 建立相关类和包结构,如下图所示:

 

  1. 各类代码如下:

package com.sxt.po;

 

import javax.persistence.Entity;

import javax.persistence.GeneratedValue;

import javax.persistence.GenerationType;

import javax.persistence.Id;

 

@Entity

public class User {

    @Id

    @GeneratedValue(strategy=GenerationType.AUTO)

    private int id;

    private String uname;

    public int getId() {

       return id;

    }

    public void setId(int id) {

       this.id = id;

    }

    public String getUname() {

       return uname;

    }

    public void setUname(String uname) {

       this.uname = uname;

    }

}

package com.sxt.dao;

 

import org.springframework.orm.hibernate3.HibernateTemplate;

 

import com.sxt.po.User;

 

public class UserDao {

         private HibernateTemplate hibernateTemplate;

        

         public void add(User u){

                   System.out.println("UserDao.add()");

                   hibernateTemplate.save(u);

         }

 

         public HibernateTemplate getHibernateTemplate() {

                   return hibernateTemplate;

         }

 

         public void setHibernateTemplate(HibernateTemplate hibernateTemplate) {

                   this.hibernateTemplate = hibernateTemplate;

         }

        

}

package com.sxt.service;

 

import com.sxt.dao.UserDao;

import com.sxt.po.User;

 

public class UserService {

        

         private UserDao userDao;

        

         public void add(String uname){

                   System.out.println("UserService.add()");

                   User u = new User();

                   u.setUname(uname);

                   userDao.add(u);

         }

 

         public UserDao getUserDao() {

                   return userDao;

         }

 

         public void setUserDao(UserDao userDao) {

                   this.userDao = userDao;

         }

        

}

package com.sxt.action;

 

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

 

import org.springframework.web.servlet.ModelAndView;

import org.springframework.web.servlet.mvc.Controller;

 

import com.sxt.service.UserService;

 

public class UserController implements Controller {

 

         private UserService userService;

        

         @Override

         public ModelAndView handleRequest(HttpServletRequest req,

                            HttpServletResponse resp) throws Exception {

                   System.out.println("HelloController.handleRequest()");

                   req.setAttribute("a", "aaaa");

                   userService.add(req.getParameter("uname"));

                   return new ModelAndView("index");

         }

 

         public UserService getUserService() {

                   return userService;

         }

 

         public void setUserService(UserService userService) {

                   this.userService = userService;

         }

 

        

}

 

  1. 运行测试:

结果为:

 

 

 

基于spring 3.0mvc 框架的文件上传实现

1. spring使用了apache-commons下得上传组件,因此,我们需要引入两个jar包:

  1. apache-commons-fileupload.jar
  2. apache-commons-io.jar

 

2.  在springmvc-servlet.xml配置文件中,增加CommonsMultipartResoler配置:

<!-- 处理文件上传 -->

<bean id="multipartResolver" 

    class="org.springframework.web.multipart.commons.CommonsMultipartResolver"

    <property name="defaultEncoding" value="gbk"/> <!-- 默认编码 (ISO-8859-1) --> 

    <property name="maxInMemorySize" value="10240"/> <!-- 最大内存大小 (10240)--> 

    <property name="uploadTempDir" value="/upload/"/> <!-- 上传后的目录名 (WebUtils#TEMP_DIR_CONTEXT_ATTRIBUTE) --> 

    <property name="maxUploadSize" value="-1"/> <!-- 最大文件大小,-1为无限止(-1) --> 

</bean>

 

3.  建立upload.jsp页面,内容如下:

        

<%@ page language="java" import="java.util.*" pageEncoding="gbk"%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">

<html>

    <head>

       <title>测试springmvc中上传的实现</title>

    </head>

    <body>

<form action="upload.do"  method="post" enctype="multipart/form-data">

           <input type="text" name="name" />

           <input type="file" name="file" />

           <input type="submit" />

       </form>

    </body>

</html>

 

4. 建立控制器,代码如下:

        

package com.sxt.web;

 

import java.io.File;

import java.util.Date;

 

import javax.servlet.ServletContext;

 

import org.springframework.stereotype.Controller;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.bind.annotation.RequestMethod;

import org.springframework.web.bind.annotation.RequestParam;

import org.springframework.web.context.ServletContextAware;

import org.springframework.web.multipart.commons.CommonsMultipartFile;

 

@Controller

public class FileUploadController implements ServletContextAware {

 

         private ServletContext servletContext;

        

         @Override

         public void setServletContext(ServletContext context) {

                   this.servletContext  = context;

         }

        

         @RequestMapping(value="/upload.do", method = RequestMethod.POST)

         public String handleUploadData(String name,@RequestParam("file")[微软用户2] CommonsMultipartFile file){

                   if (!file.isEmpty()) {

                               String path = this.servletContext.getRealPath("/tmp/");  //获取本地存储路径

                               System.out.println(path);

                               String fileName = file.getOriginalFilename();

                               String fileType = fileName.substring(fileName.lastIndexOf("."));

                               System.out.println(fileType);

                               File file2 = new File(path,new Date().getTime() + fileType); //新建一个文件

                               try {

                                         file.getFileItem().write(file2); //将上传的文件写入新建的文件中

                               } catch (Exception e) {

                                         e.printStackTrace();

                               }

                               return "redirect:upload_ok.jsp";

                            }else{

                                     return "redirect:upload_error.jsp";

                            }

         }

}

 

5. 建立upload_ok.jsp页面

<%@ page language="java" import="java.util.*" pageEncoding="gbk"%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">

<html>

  <head>

  </head>

  <body>

       <h1>上传成功!</h1>

  </body>

</html>

 

6. 建立upload_error.jsp页面

  <%@ page language="java" import="java.util.*" pageEncoding="gbk"%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">

<html>

  <head>

  </head>

  <body>

       <h1>上传失败!</h1>

  </body>

</html>

 

  1. 发布项目,运行测试:http://localhost:8080/springmvc03/upload.jsp

 

   进入项目发布后的目录,发现文件上传成功:

 

 

处理ajax请求

spring使用了jackson类库,帮助我们在java对象和json、xml数据之间的互相转换。他可以将控制器返回的对象直接转换成json数据,供客户端使用。客户端也可以传送json数据到服务器进行直接转换。使用步骤如下:

 

1.  项目中需要引入如下两个jar包:

                  jackson-core-asl-1.7.2jar

                   jackson-mapper-asl-1.7.2jar

2.  spring配置文件中修改:

             <mvc:annotation-driven />  <!-- 支持spring3.0新的mvc注解 -->

    <!-- 启动Spring MVC的注解功能,完成请求和注解POJO的映射 -->

      <bean class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter"

        <property name="cacheSeconds" value="0" /> 

        <property name="messageConverters"

            <list> 

                <bean class="org.springframework.http.converter.json.MappingJacksonHttpMessageConverter"></bean> 

            </list> 

        </property>

    </bean>  

 

  1. 客户端代码a.jsp如下:

<%@ page language="java" import="java.util.*" pageEncoding="gbk"%>

<%

String path = request.getContextPath();

String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";

%>

 

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">

<html>

  <head>

    <base href="<%=basePath%>">

   

    <title>My JSP ‘index.jsp‘ starting page</title>

    <meta http-equiv="pragma" content="no-cache">

    <meta http-equiv="cache-control" content="no-cache">

    <meta http-equiv="expires" content="0">   

    <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">

    <meta http-equiv="description" content="This is my page">

    <script>

       function createAjaxObj(){

           var req;

           if(window.XMLHttpRequest){

              req = new XMLHttpRequest();

           }else{

              req = new ActiveXObject("Msxml2.XMLHTTP");  //ie

           }

           return req;

       }

      

       function sendAjaxReq(){

           var req = createAjaxObj();

           req.open("get","myajax.do?method=test2&uname=张三");

           req.setRequestHeader("accept","application/json");

           req.onreadystatechange  = function(){

              eval("var result="+req.responseText);

              document.getElementById("div1").innerHTML=result[0].uname;

           }

           req.send(null);

       }

    </script>

  </head>

 

  <body>

    <a href="javascript:void(0);" onclick="sendAjaxReq();">测试</a>

    <div id="div1"></div>

  </body>

</html>

 

 

  1. 服务器端代码如下:

        

package com.sxt.web;

 

import java.io.UnsupportedEncodingException;

import java.util.ArrayList;

import java.util.List;

 

import org.springframework.stereotype.Controller;

import org.springframework.web.bind.annotation.RequestBody;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.bind.annotation.RequestMethod;

import org.springframework.web.bind.annotation.ResponseBody;

 

import com.sxt.po.User;

 

@Controller

@RequestMapping("myajax.do")

public class MyAjaxController {

        

         @RequestMapping(params="method=test1",method=RequestMethod.GET)

         public @ResponseBody List<User> test1(String uname) throws Exception{

                   String uname2 = new String(uname.getBytes("iso8859-1"),"gbk");

                   System.out.println(uname2);

                   System.out.println("MyAjaxController.test1()");

                   List<User> list = new ArrayList<User>();

                   list.add(new User("高淇","123"));

                   list.add(new User("马士兵","456"));

                  

                   return list;

         }

        

}

 

 

  1. 测试。

a)         启动服务器。输入:http://localhost:8080/springmvc03/a.jsp

 

 

 

 

 

 

 

Spring中的拦截器

定义spring拦截器两种基本方式

  1. 实现接口:org.springframework.web.servlet.HandlerInterceptor。

接口中有如下方法需要重写:

注意:参数中的Object handler是下一个拦截器。

a)         public boolean preHandle
(HttpServletRequest request,HttpServletResponse response,
Object handler) throws Exception

该方法在action执行前执行,可以实现对数据的预处理,比如:编码、安全控制等。

如果方法返回true,则继续执行action。

b)         public void postHandle
(HttpServletRequest request,HttpServletResponse response,
Object handler,   ModelAndView modelAndView) throws Exception

该方法在action执行后,生成视图前执行。在这里,我们有机会修改视图层数据。

c)         public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex)   throws Exception

最后执行,通常用于释放资源,处理异常。我们可以根据ex是否为空,来进行相关的异常处理。因为我们在平时处理异常时,都是从底层向上抛出异常,最后到了spring框架从而到了这个方法中。

  1. 继承适配器:
    org.springframework.web.servlet.handler.HandlerInterceptorAdapter

这个适配器实现了HandlerInterceptor接口。提供了这个接口中所有方法的空实现。

 

如下我们写出两个拦截器的示例代码,仅供大家参考:

package com.sxt.interceptor;

 

import javax.interceptor.Interceptors;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

 

import org.springframework.web.servlet.HandlerInterceptor;

import org.springframework.web.servlet.ModelAndView;

 

 

public class MyInterceptor implements HandlerInterceptor {

 

    @Override

    public void afterCompletion(HttpServletRequest request,    HttpServletResponse response, Object handler, Exception ex)    throws Exception {

       System.out.println("最后执行!!!一般用于释放资源!!");

      

    }

 

    @Override

    public void postHandle(HttpServletRequest request,HttpServletResponse response, Object handler,    ModelAndView modelAndView) throws Exception {

       System.out.println("Action执行之后,生成视图之前执行!!");

    }

 

    @Override

    public boolean preHandle(HttpServletRequest request,HttpServletResponse response, Object handler) throws Exception {

       System.out.println("action之前执行!!!");

       return true;  //继续执行action

    }

 

}

 

package com.sxt.interceptor;

 

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

 

import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;

 

 

public class MyInterceptor2 extends HandlerInterceptorAdapter {

 

    @Override

    public boolean preHandle(HttpServletRequest request,HttpServletResponse response, Object handler) throws Exception {

       System.out.println("MyInterceptor2.preHandle()");

       return true;  //继续执行action

    }

 

}

 

 

 

  1. XML中如何配置。如下为示例代码:

    <mvc:interceptors>

       <bean class="com.sxt.interceptor.MyInterceptor"></bean> <!-- 拦截所有springmvcurl! -->

       <mvc:interceptor>

           <mvc:mapping path="/user.do" />

           <!--<mvc:mapping path="/test/*" />-->

           <bean class="com.sxt.interceptor.MyInterceptor2"></bean>

       </mvc:interceptor>

    </mvc:interceptors>

 

 


将属性u的值赋给形参uname

一定要加。

郑重声明:本站内容如果来自互联网及其他传播媒体,其版权均属原媒体及文章作者所有。转载目的在于传递更多信息及用于网络分享,并不代表本站赞同其观点和对其真实性负责,也不构成任何其他建议。