springMVC 过程过程描述

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

Java代码

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：

Java代码

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;

}

@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;

}

}

}

applicationContext.xml

Html代码

<?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：

Html代码

<%@ 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>

login.jsp

Html代码

<%@ 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

Html代码

<%@ 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

Html代码

<?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>