走进spring之springmvc
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
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。
分类: 走进spring
走进spring之springmvc
时间： 2024-08-08 09:34:01