走进spring之springmvc实战篇（一）
本篇运用springmvc来试着写一个登录注册页面
在动手之前，我们需要了解下springnvc.这里先献上一张springmvc的流程图及讲解。
Spring的MVC框架是一个基于DispatcherServlet的MVC框架，主要由DispatcherServlet、处理器映射、处理器、视图解析器、视图组成。每一个请求最先访问的都是DispatcherServlet，DispatcherServlet负责转发每一个Request请求给相应的Handler，Handler处理以后再返回相应的视图(View)和模型(Model)，返回的视图和模型都可以不指定，即可以只返回Model或只返回View或都不返回。
Spring MVC的原理框图:
整个处理过程从一个HTTP请求开始：
1）DispatcherServlet接收到请求后，根据对应配置文件中配置的处理器映射，找到对应的处理器映射项（HandlerMapping），根据配置的映射规则，找到对应的处理器（Handler）。
2）调用相应处理器中的处理方法，处理该请求，处理器处理结束后会将一个ModelAndView类型的数据传给DispatcherServlet，这其中包含了处理结果的视图和视图中要使用的数据。
3）DispatcherServlet根据得到的ModelAndView中的视图对象，找到一个合适的ViewResolver（视图解析器），根据视图解析器的配置，DispatcherServlet将视图要显示的数据传给对应的视图，最后给浏览器构造一个HTTP响应。
DispatcherServlet是整个Spring MVC的核心。它负责接收HTTP请求组织协调Spring MVC的各个组成部分。其主要工作有以下三项：
1）截获符合特定格式的URL请求。
2）初始化DispatcherServlet上下文对应的WebApplicationContext，并将其与业务层、持久化层的WebApplicationContext建立关联。
3）初始化Spring MVC的各个组成组件，并装配到DispatcherServlet中
此时，我们已经对springmvc有了一定的了解，如果您对还理不清思路，没关系，下面让我们来进行实战演练，边练边学。
首先，让我们梳理下整体步骤：
1）导入包：springframework-3.0.RELEASE全部的包，servlet-api.jar,spring-webmvc.jar,spring.jar,comoms-logging.jar，jstl.jar
2）配置/WEB-INF下的web.xml,spring配置文件spring-servlet.xml,上下文applicationContext.xml
3）创建相关类：
4）创建/WEB-INF/jsp下的jsp页面
开始配置XML文件！
web.xml
这里我们定义了请求分发Servlet，即：org.springframework.web.servlet.DispatcherServlet
DispatcherServlet 是Spring MVC 中负责请求调度的核心引擎，所有的请求将由此Servlet 根据配置分发至各个逻辑处理单元。其内部同时也维护了一个ApplicationContext实例。
<?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" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" version="2.5"> <display-name>mvc_loginregist</display-name> <!-- servlet定义 --> <servlet> <servlet-name>spring</servlet-name> <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class> <!-- 可以自定义servlet.xml配置文件的位置和名称，默认为WEB-INF目录下，名称为[<servlet-name>]-servlet.xml，如spring-servlet.xml <init-param> <param-name>contextConfigLocation</param-name> <param-value>/WEB-INF/spring-servlet.xml</param-value> </init-param> --> <!-- 设置启动的优先级，这里表示表示启动容器时初始化该Servlet --> <load-on-startup>1</load-on-startup> </servlet> <!--通过将DispatcherServlet映射到/，声明了它会作为默认的servlet并且会处理所有请求，包括对静态资源的请求--> <servlet-mapping> <servlet-name>spring</servlet-name> <url-pattern>/</url-pattern> </servlet-mapping> <!-- 配置ContextLoaderListerner --> <listener> <listener-class> org.springframework.web.context.ContextLoaderListener </listener-class> </listener> <!-- 可以配置contextConfigLocation初始化参数 <context-param> <param-name>contextConfigLocation</param-name> <param-value>/WEB-INF/court-servlet.xml</param-value> </context-param> 默认初始化参数为 <context-param> <param-name>contextConfigLocation</param-name> <param-value>/WEB-INF/applicationContext.xml</param-value> </context-param> 这里使用默认参数 --> <!-- 跳转至首页,首页访问地址为http://localhost:8080/项目名--> <welcome-file-list> <welcome-file>/WEB-INF/jsp/login.jsp</welcome-file> </welcome-file-list> </web-app>
sping-servlet.xml
InternalResourceViewResolver在web应用程序的war文件中查找视图模板。视图模块的路径根据加完前缀和后缀的逻辑视图名称来确定，若返回“login”作为逻辑试图名称时，它最终会被解析成"/WEB-INF/jsp/login.jsp"路径
<?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"> <!-- ViewResolver 指定了表现层资源的前缀和后缀 --> <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"> <property name="viewClass" value="org.springframework.web.servlet.view.JstlView"/> <property name="prefix" value="/WEB-INF/jsp/"/> <property name="suffix" value=".jsp"/> </bean> <!--配置处理器映射--> <bean id="loginMapping" class="org.springframework.web.servlet.handler.SimpleUrlHandlerMapping"> <property name="mappings"> <props> <prop key="doLogin">loginAction</prop><!-- 首字母必须小写,请求"doLogin"对应loginAction处理 --> <prop key="doRegist">registAction</prop> <prop key="toRegist">toRegistAction</prop> <prop key="toLogin">toLoginAction</prop> </props> </property> </bean> </beans>
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" xsi:schemaLocation=" http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd"> <!-- 定义ToRegistAction --> <bean id="toRegistAction" class="com.htgy.actions.ToRegistAction"> </bean> <!-- 定义ToLoginAction --> <bean id="toLoginAction" class="com.htgy.actions.ToLoginAction"> </bean> <!-- 添加处理器配置 --> <!---定义LoginAction类--> <bean id="loginAction" class="com.htgy.actions.LoginAction"> <property name="commandClass"> <value>com.htgy.loginform.LoginForm</value> </property> <!-- 指定失败要返回的页面 --> <!-- 需修改 --> <property name="lFailView"> <value>loginFail</value> </property> <!-- 指定成功要返回的页面 --> <property name="lSuccessView"> <value>loginSuccess</value> </property> </bean> <!-- 定义RegistAction --> <bean id="registAction" class="com.htgy.actions.RegistAction"> <property name="commandClass"> <value>com.htgy.registform.RegistForm</value> </property> <!-- 注册成功返回的页面 --> <property name="rSuccessView"> <value>registSuccess</value> </property> <!-- 取消注册返回的页面 --> <property name="rFailView"> <value>registFail</value> </property> </bean> </beans>
下面是java类
LoginAction和RegistAction类继承了SimpleFormController，它是AbstractFormController的具体实现其功能是从表单中提取参数封装到command。
LoginAction类
package com.htgy.actions; /* * 登录Controller层 */ import java.util.HashMap; import java.util.LinkedList; import java.util.List; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.springframework.validation.BindException; import org.springframework.web.servlet.ModelAndView; import org.springframework.web.servlet.mvc.SimpleFormController; import com.htgy.loginform.LoginForm; public class LoginAction extends SimpleFormController { private String lFailView; private String lSuccessView; public String getLFailView() { return lFailView; } public void setLFailView(String lFailView) { this.lFailView = lFailView; } public String getLSuccessView() { return lSuccessView; } public void setLSuccessView(String lSuccessView) { this.lSuccessView = lSuccessView; } @Override protected ModelAndView onSubmit(HttpServletRequest request, HttpServletResponse response, Object command, BindException errors) throws Exception { //讲表单的参数封装到command中 LoginForm lf = (LoginForm)command; if (lf.getAccount().equals("111111") && lf.getPassword().equals("123456")){ HashMap<String, Object> map = new HashMap<String, Object>(); map.put("LoginForm", lf); List<String> msgList = new LinkedList<String>(); msgList.add("你好，Spring MVC"); map.put("msg", msgList); System.out.println("登录成功"); //返回视图和模型，this.getLSuccessView()为视图，map为模型 return new ModelAndView(this.getLSuccessView(),map); }else{ return new ModelAndView(this.getLFailView()); } } }
RegsitAction类
package com.htgy.actions; /* * 注册Controller层 */ import java.util.HashMap; import java.util.LinkedList; import java.util.List; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.springframework.validation.BindException; import org.springframework.web.servlet.ModelAndView; import org.springframework.web.servlet.mvc.SimpleFormController; import com.htgy.registform.RegistForm; public class RegistAction extends SimpleFormController{ private String rFailView; private String rSuccessView; public String getRFailView() { return rFailView; } public void setRFailView(String rFailView) { this.rFailView = rFailView; } public String getRSuccessView() { return rSuccessView; } public void setRSuccessView(String rSuccessView) { this.rSuccessView = rSuccessView; } @Override protected ModelAndView onSubmit(HttpServletRequest request, HttpServletResponse response, Object command, BindException errors) throws Exception { //讲表单的参数封装到command中 RegistForm rf = (RegistForm)command; if (rf.getAccount().equals("111111") && rf.getPassFirst().equals("123456") &&rf.getPassSecond().equals("123456")){ HashMap<String, Object> map = new HashMap<String, Object>(); map.put("LoginForm", rf); List<String> msgList = new LinkedList<String>(); msgList.add("你好，Spring MVC"); map.put("msg", msgList); //返回视图和模型，this.getRSuccessView()为视图，map为模型 return new ModelAndView(this.getRSuccessView(),map); }else{ return new ModelAndView(this.getRFailView()); } } }
SimpleFormController类中的onsubmit方法用于获取表单传递的信息
ToLoginAction类
package com.htgy.actions; /* * 跳转到login.jsp页面 */ import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.springframework.web.servlet.ModelAndView; import org.springframework.web.servlet.mvc.Controller; public class ToLoginAction implements Controller { @Override public ModelAndView handleRequest(HttpServletRequest req, HttpServletResponse resp) throws Exception { return new ModelAndView("login"); } }
ToRegistAction类
package com.htgy.actions; /* * 跳转到regist.jsp页面 */ import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.springframework.web.servlet.ModelAndView; import org.springframework.web.servlet.mvc.Controller; public class ToRegistAction implements Controller { @Override public ModelAndView handleRequest(HttpServletRequest req, HttpServletResponse resp) throws Exception { return new ModelAndView("regist"); } }
Controller接口仅仅声明了一个方法handleRequest，它负责处理请求并返回合适的模型和视图。
LoginForm类
package com.htgy.loginform; /* * 登录表单类 */ public class LoginForm { private String account; private String password; public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } public String getAccount() { return account; } public void setAccount(String account) { this.account = account; } }
RegistForm类
package com.htgy.registform; /* * 注册表单类 */ public class RegistForm { private String account; private String passFirst; private String passSecond; public String getAccount() { return account; } public void setAccount(String account) { this.account = account; } public String getPassFirst() { return passFirst; } public void setPassFirst(String passFirst) { this.passFirst = passFirst; } public String getPassSecond() { return passSecond; } public void setPassSecond(String passSecond) { this.passSecond = passSecond; } }
表单类必须具有set和get方法，便于请求的封装和提取。
jsp页面
login.jsp
<%@ page language="java" import="java.util.*" contentType="text/html; charset=utf-8"%> <% 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>登录</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"> <!-- <link rel="stylesheet" type="text/css" href="styles.css"> --> </head> <body> <center> <h1>登陆</h1> <hr> <% request.setCharacterEncoding("utf-8"); //解决中文乱码问题 %> <form name="regForm" action="doLogin" method="post"> <table> <tr> <td>账号：</td> <td><input type="text" name="account" /> </td> </tr> <tr> <td>密码：</td> <td><input type="password" name="password" /> </td> </tr> </table> <table> <tr> <td colspan="1"><input type="submit" value="登录" /></td> <td colspan="1"><input type="reset" value="重置" /></td> </tr> </table> </form> <br>还没有账号？请注册<input type="button" value="注册" onclick="window.location.href='toRegist'"/> </center> </body> </html>
loginFail.jsp
<%@ page language="java" import="java.util.*" contentType="text/html; charset=utf-8"%> <% 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>登录失败</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"> <!-- <link rel="stylesheet" type="text/css" href="styles.css"> --> </head> <body> <center> 登录失败<a href="toLogin">返回登录界面</a> </center> </body> </html>
loginSuccess.jsp
<%@ page language="java" import="java.util.*" contentType="text/html; charset=utf-8"%> <% 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>登录成功</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"> <!-- <link rel="stylesheet" type="text/css" href="styles.css"> --> </head> <body> <center> <h1>登陆成功！！！！！！！！！！</h1> <hr> </center> </body> </html>
regist.jsp
<%@ page language="java" import="java.util.*" contentType="text/html; charset=utf-8"%> <% 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>注册</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"> <!-- <link rel="stylesheet" type="text/css" href="styles.css"> --> </head> <body> <center> <% request.setCharacterEncoding("utf-8"); //解决中文乱码问题 %> <h1>注册</h1><hr> <form name="regform" action="doRegist" method="post"> <table> <tr> <td>账号：</td> <td><input type="text" name="account" id="account" maxLength="10"></td> </tr> <tr> <td>密码：</td> <td><input type="password" name="passFirst" id="passFirst" maxLength="12" /> </td> </tr> <tr> <td>确认密码：</td> <td><input type="password" name="passSecond" id="passSecond" maxLength="12" /> </tr> <tr> <td>用户名：</td> <td><input type="text" name="username" maxLength="9"/></td> </tr> </table> <table> <tr> <td colspan="1"><input type="submit" value="注册" /></td> <td colspan="1"><input type="reset" value="重置" /></td> </tr> </table> </form> <form name="regForm" action="toLogin"> <table> <tr> <td colspan="2"><input type="submit" value="返回登录界面" /> </td> </tr> </table> </form> </center> </body> </html>
registFail.jsp
<%@ page language="java" import="java.util.*" contentType="text/html; charset=utf-8"%> <% 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>注册失败</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"> <!-- <link rel="stylesheet" type="text/css" href="styles.css"> --> </head> <body> <center> 注册失败<br> <a href="toRegist">继续注册</a> <a href="toLogin">返回登录界面</a> </center> </body> </html>
registSuccess.jsp
<%@ page language="java" import="java.util.*" contentType="text/html; charset=utf-8"%> <% 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>注册成功</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"> <!-- <link rel="stylesheet" type="text/css" href="styles.css"> --> </head> <body> <center> <h1>恭喜您！注册成功</h1><hr> 返回登陆页面？<a href="toLogin"/>确定</a> </center> </body> </html>
大功告成！~
本篇只是让大家初步了解了springmvc的构建和运行原理，之后我们再通过加入数据库来进行更深层次的了解。
总结：
1）在最开始接触springmvc时候，经常会把请求和视图搞反，正确的理解应该是客户传递请求给dispatcherServlet，dispatcherServlet处理请求后再将相应的视图传递给客户。
