参考:http://www.zuidaima.com/share/1751859714182144.htm
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
那你猜一猜哪一部分应该是哪一部分?
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
1.Account 实体类
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; } }
2. 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 { /*这两个字段名不能随便瞎取,必须与SpringMVC的配置文件中的Controller的property保持一致,如下图 <bean id="loginController" class="com.pb.web.controller.LoginController"> <property name="successView" value="showAccount"></property> <property name="failView" value="login"></property> </bean> */ private String successView; private String failView; @Override protected ModelAndView handleRequestInternal(HttpServletRequest request, HttpServletResponse response) throws Exception { // TODO Auto-generated method stub String 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; } } 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; } }
说明:
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" 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>SpringMVCDemo</display-name> <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> <!-- spring mvc配置文件名称,默认名称为dispatcher-servlet.xml。如果更名后,需要在这里配置。如果是将springmvc的配置文件更名为applicationContext.xml后配置情况 <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>
编写springmvc配置文件,在WEB-INF目录下面建立dispatcher-servlet.xml文件
说明:DispatcherServlet默认加载的是WEB-INF目录下dispatcher-servlet.xml文件,但是也可以替换成其它的名字(比如:applicationContext.xml)。这样的话就需要在web.xml中做额外的配置了
<?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.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd"> <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="loginController" class="com.pb.web.controller.LoginController"> <property name="successView" value="showAccount"></property> <property name="failView" value="login"></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>
Login.jsp页面
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4. Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=GB0"> <title>Insert title here</title> </head> <body> ${error } <form action="login.do" method="post"> 账号登陆<br> <hr> 卡号:<input type="text" name="cardNo"><br> 密码:<input type="text" name="password"><br> <input type="submit" value="登陆"> </form> </body> </html>
showAccount.jsp页面
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=GB0"> <title>Insert title here</title> </head> <body> 账户信息 <br> 卡号:${account.cardNo } <br> 密码:${account.password } <br> 钱数:${account.balance } <br> <h1>${user.username }</h1> <h2>${user.password }</h2> </body> </html>