SpringMVC入门

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SpringMVC框架介绍

Spring框架提供了构造Web应用程序的全能MVC模块。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制定。是一个标准

的MVC框架。

SpringMVC框架图

SpringMVC接口解释

DispatcherServlet接口：

Spring提供的前端控制器，所有的请求都有经过它来统一分发。在DispatcherServlet将请求分发给Spring Controller之前，需要借助于Spring提供的HandlerMapping定位到具体的Controller。

HandlerMapping接口：

能够完成客户请求到Controller映射。

Controller接口：

需要为并发用户处理上述请求，因此实现Controller接口时，必须保证线程安全并且可重用。Controller将处理用户请求，这和Struts Action扮演的角色是一致的。一旦Controller处理完用户请求，则返回ModelAndView对象给DispatcherServlet前端控制器，ModelAndView中包含了模型（Model）和视图（View）。从宏观角度考虑，DispatcherServlet是整个Web应用的控制器；从微观考虑，Controller是单个Http请求处理过程中的控制器，而ModelAndView是Http请求过程中返回的模型（Model）和视图（View）。

ViewResolver接口：

Spring提供的视图解析器（ViewResolver）在Web应用中查找View对象，从而将相应结果渲染给客户。

SpringMVC运行原理

1. 客户端请求提交到DispatcherServlet

2. 由DispatcherServlet控制器查询一个或多个HandlerMapping，找到处理请求的Controller

3. DispatcherServlet将请求提交到Controller

4. Controller调用业务逻辑处理后，返回ModelAndView

5. DispatcherServlet查询一个或多个ViewResoler视图解析器，找到ModelAndView指定的视图

6. 视图负责将结果显示到客户端

SpringMVC运行实例

package com.pb.entity;public class Account {private String cardNo;private String password;private float balance;public String getCardNo() {return cardNo;}public void setCardNo(String cardNo) {this.cardNo = cardNo;}public String getPassword() {return password;}public void setPassword(String password) {this.password = password;}public float getBalance() {return balance;}public void setBalance(float balance) {this.balance = balance;}}

LoginController类：

package com.pb.web.controller;import java.util.HashMap;import java.util.Map;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import org.springframework.web.servlet.ModelAndView;import org.springframework.web.servlet.mvc.AbstractController;import com.pb.entity.Account;public class LoginController extends AbstractController {private String successView;private String failView;//这两个参数是返回值传给applicationContext.xml，进行页面分配public String getSuccessView() {return successView;}public void setSuccessView(String successView) {this.successView = successView;}public String getFailView() {return failView;}public void setFailView(String failView) {this.failView = failView;}@Overrideprotected ModelAndView handleRequestInternal(HttpServletRequest request,HttpServletResponse response) throws Exception {// TODO Auto-generated method stubString cardNo=request.getParameter("cardNo");String password=request.getParameter("password");Account account =getAccount(cardNo,password);Map<String ,Object> model=new HashMap<String,Object>();if(account !=null){model.put("account", account);return new ModelAndView(getSuccessView(),model);}else{model.put("error", "卡号和密码不正确");return new ModelAndView(getFailView(),model);}}//本应该这个方法写在模型层，这地方直接给放在了逻辑层这个地方偷懒了。public Account getAccount(String cardNo,String password){if(cardNo.equals("123")&&password.equals("123")){Account account =new Account();account.setCardNo(cardNo);account.setBalance(88.8f);return account;}else{return null;}}}

applicationContext.xml

<?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"     xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.0.xsd           http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-2.0.xsd           http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-2.0.xsd"><bean id="loginController" class="com.pb.web.controller.LoginController"><property name="successView" value="showAccount"></property><property name="failView" value="login"></property></bean><bean id="urlMapping" class="org.springframework.web.servlet.handler.SimpleUrlHandlerMapping"><property name="mappings"><props><prop key="/login.do">loginController</prop></props></property></bean><bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver"><property name="prefix" value="/"></property><property name="suffix" value=".jsp"></property></bean></beans>

jsp页面

<%@ page language="java" contentType="text/html; charset=GB18030"    pageEncoding="GB18030"%><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html><head><meta http-equiv="Content-Type" content="text/html; charset=GB18030"><title>Insert title here</title></head><body><a href="login.jsp">进入</a></body></html>

<%@ page language="java" contentType="text/html; charset=GB18030"    pageEncoding="GB18030"%><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html><head><meta http-equiv="Content-Type" content="text/html; charset=GB18030"><title>Insert title here</title></head><body>${error }    <form action="login.do" method="post">        账号登陆<br>        <hr>                卡号：<input type="text" name="cardNo"><br>        密码：<input type="text" name="password"><br>        <input type="submit" value="登陆">    </form></body></html>

showAccount.jsp

<%@ page language="java" contentType="text/html; charset=GB18030"    pageEncoding="GB18030"%><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html><head><meta http-equiv="Content-Type" content="text/html; charset=GB18030"><title>Insert title here</title></head><body>账户信息<br>卡号：${account.cardNo }<br>密码：${account.password }<br>钱数：${account.balance }<br></body></html>

Web.xml

<?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/j2ee" xmlns:javaee="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/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd" version="2.4">  <welcome-file-list>    <welcome-file>index.jsp</welcome-file>  </welcome-file-list>  <servlet>  <servlet-name>Dispatcher</servlet-name>  <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>  <init-param>  <param-name>contextConfigLocation</param-name>  <param-value>classpath:applicationContext.xml</param-value>  </init-param>  </servlet>  <servlet-mapping>  <servlet-name>Dispatcher</servlet-name>  <url-pattern>*.do</url-pattern>  </servlet-mapping>  </web-app>

SpringMVC总结

以上就是我理解的Spring MVC可能不够深刻。其实对于任何的框架来说，一个框架是一个可复用设计，框架的最大的好处就是复用。每个框架都有存在的理由，那Spring MVC的理由是什么呢？
只有各个框架之间彼此了解他们之间的优缺点，使用场合，使用原理，才能让我们的更快的成长。

原网址 http://blog.csdn.net/qiulongtianshi/article/details/7772088#

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