Spring框架提供了構造Web應用程序的全能MVC模塊。Spring MVC分離了控制器、模型對象、分派器以及處理程序對象的角色，這種分離讓它們更容易進行制定。是一個標準的MVC框架。

那你猜一猜哪一部分應該是哪一部分？

SpringMVC框架圖

SpringMVC接口解釋

DispatcherServlet接口：

Spring提供的前端控制器，所有的請求都有經過它來統一分發。在DispatcherServlet將請求分發給Spring Controller之前，需要藉助於Spring提供的HandlerMapping定位到具體的Controller。

HandlerMapping接口：

能夠完成客戶請求到Controller映射。

Controller接口：

需要爲併發用戶處理上述請求，因此實現Controller接口時，必須保證線程安全並且可重用。Controller將處理用戶請求，這和Struts Action扮演的角色是一致的。一旦Controller處理完用戶請求，則返回ModelAndView對象給DispatcherServlet前端控制器，ModelAndView中包含了模型（Model）和視圖（View）。從宏觀角度考慮，DispatcherServlet是整個Web應用的控制器；從微觀考慮，Controller是單個Http請求處理過程中的控制器，而ModelAndView是Http請求過程中返回的模型（Model）和視圖（View）。

ViewResolver接口：

Spring提供的視圖解析器（ViewResolver）在Web應用中查找View對象，從而將相應結果渲染給客戶。

SpringMVC運行原理

1.客戶端請求提交到DispatcherServlet

2.由DispatcherServlet控制器查詢一個或多個HandlerMapping，找到處理請求的Controller

3.DispatcherServlet將請求提交到Controller

4.Controller調用業務邏輯處理後，返回ModelAndView

5.DispatcherServlet查詢一個或多個ViewResoler視圖解析器，找到ModelAndView指定的視圖

6.視圖負責將結果顯示到客戶端

SpringMVC運行實例

Account類：

Java代碼

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類：

Java代碼

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;//這兩個參數是返回值傳給applicationContext.xml，進行頁面分配
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;
}
@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", "卡號和密碼不正確");
return new ModelAndView(getFailView(),model);
}
}//本應該這個方法寫在模型層，這地方直接給放在了邏輯層這個地方偷懶了。
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

Html代碼

<?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頁面：

Html代碼

<%@ 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">進入</a>
</body>
</html>

Html代碼

<%@ 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">
賬號登陸
<hr>
卡號：<input type="text" name="cardNo">
密碼：<input type="text" name="password">
<input type="submit" value="登陸">
</form>
</body>
</html>

showAccount.jsp

Html代碼

<%@ 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>
賬戶信息
卡號：${account.cardNo }
密碼：${account.password }
錢數：${account.balance }
</body>
</html>

Web.xml

Html代碼

<?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>