自定义Struts框架实现登陆功能

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MVC模式:

Model 模型

View 视图

Control 控制器

传统MVC开发缺陷：

在实现页面跳转的时候跳转的代码写死了，不够灵活。

在传统的MVC开发中Servlet的使用和配置太过于频繁

下面我们就使用登陆的案例来简单演示一波MVC的优化

文件结构图如下:

同时需要引入dom4j的jar包

首先，我们建立一个User的实体类

public class User implements Serializable{private String userName;private String pwd;public String getUserName() {return userName;}public void setUserName(String userName) {this.userName = userName;}public String getPwd() {return pwd;}public void setPwd(String pwd) {this.pwd = pwd;}}

接下来我们开始写登陆的界面login.jsp

<%@ page language="java" import="java.util.*" pageEncoding="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>登陆界面</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">  </head>  <body>  <form action="${pageContext.request.contextPath}/login.action" name="login_from" method="post">  用户名:<input type="text" name="username"/><br/>  密 码:<input type="password" name="pwd"/><br/> <input type="submit" value="提交" />  </form>  </body></html>

主页

<%@ page language="java" import="java.util.*" pageEncoding="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>首页</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">  </head>  <body>  <h2>欢迎你,${sessionScope.userInfo.userName}</h2>  </body></html>

然后写一个UserDao对传入的参数进行处理,然后将处理的结果以对象的形式进行返回

package cn.qblank.dao;import cn.qblank.entity.User;public class UserDao {//模拟登陆public User login(User user){//判断是否登陆成功if ("admin".equals(user.getUserName()) && "123".equals(user.getPwd())) {return user;}//登陆失败return null;}}

然后再写一个LoginAction.java处理登陆的请求,然后以字符串的形式返回一个结果集

package cn.qblank.mystruts.action;import java.io.IOException;import javax.servlet.ServletException;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import cn.qblank.entity.User;import cn.qblank.service.UserService;public class LoginAction {public Object execute(HttpServletRequest req, HttpServletResponse resp)throws ServletException, IOException {return null;}/** * 处理登陆的请求数据 * @param req * @param resp * @throws ServletException * @throws IOException */public Object login(HttpServletRequest req, HttpServletResponse resp)throws ServletException, IOException {Object uri = null;//获取参数String username = req.getParameter("username");String pwd = req.getParameter("pwd");//封转到对象中User user = new User();user.setUserName(username);user.setPwd(pwd);System.out.println(user.getUserName());//然后处理事件UserService userService = new UserService();User userInfo = userService.login(user);if (userInfo == null) {System.out.println("登陆失败");uri = "loginFiled";}else{System.out.println("登陆成功");req.getSession().setAttribute("userInfo", userInfo);uri = "loginSuccess";}return uri;}}

由于不能把配置页面写死，于是我们可以将需要配置的文件写到mystruts.xml文件中，然后对其进行读取,然后再进行跳转

<?xml version="1.0" encoding="UTF-8"?><mystruts><package><!-- name表示路径  class表示是从传入参数的类的全名   method 表示传入参数的方法名--><action name="login" class="cn.qblank.mystruts.action.LoginAction" method="login"><!-- 存储结果集  跳转 和(默认)重定向 --><result name="loginSuccess" type="redirect">/index.jsp</result><result name="loginFiled">/login.jsp</result></action></package></mystruts>

创建xml文件后，我们使用dom4j对其就行读取，然后将action封装到ActionMapping中将结果集封装到Result.java对象中

Result.java

package cn.qblank.mystruts.bean;/** * 封转结果视图 * @author Administrator *<result name="success" type="redirect">/index.jsp</result> */public class Result {//跳转结果标记private String name;//跳转类型 默认为转发  "redirect"为跳转private String type;//跳转页面private String page;public String getName() {return name;}public void setName(String name) {this.name = name;}public String getType() {return type;}public void setType(String type) {this.type = type;}public String getPage() {return page;}public void setPage(String page) {this.page = page;}}

ActionMapping.java

package cn.qblank.mystruts.bean;import java.util.Map;/** * 封转action结点 * <action name="login" class="cn.itcast.framework.action.LoginAction" method="login"><result name="success" type="redirect">/index.jsp</result><result name="loginFaild">/login.jsp</result></action> * @author Administrator * */public class ActionMapping {//请求路径的名字private String name;//处理Action类的全名private String className;//处理方法private String method;//结果视图集合private Map<String, Result> results;public String getName() {return name;}public void setName(String name) {this.name = name;}public String getClassName() {return className;}public void setClassName(String className) {this.className = className;}public String getMethod() {return method;}public void setMethod(String method) {this.method = method;}public Map<String, Result> getResults() {return results;}public void setResults(Map<String, Result> results) {this.results = results;}}

读取xml中的数据，并封装到对象ActionMapping和Result对象中

package cn.qblank.mystruts.bean;import java.io.InputStream;import java.util.HashMap;import java.util.Iterator;import java.util.List;import java.util.Map;import org.dom4j.Document;import org.dom4j.Element;import org.dom4j.io.SAXReader;/** * 加载整个mystruts.xml文件 * 并将其封转到对象中 * @author Administrator * */public class ActionMappingManager {private Map<String, ActionMapping> actions;public ActionMappingManager(){actions = new HashMap<String, ActionMapping>();//初始化init();}/** * 根据请求路径名称，返回Action的映射对象 * 通过名字获取对应的ActionMapping * @param actionName   当前请求路径 * @return 返回配置文件中代表action节点的AcitonMapping对象 */public ActionMapping getActionMapping(String actionName){if (actionName == null) {throw new RuntimeException("传入参数有误，请查看struts.xml配置的路径。");}ActionMapping actionMapping = actions.get(actionName);if (actionMapping == null) {throw new RuntimeException("路径在struts.xml中找不到，请检查");}return actionMapping;}/** * 初始化集合 * 将mystruts.xml的数据封装到对象中 */@SuppressWarnings("unchecked")public void init(){try {//得到解析器SAXReader reader = new SAXReader();//得到文件流InputStream in = this.getClass().getResourceAsStream("/mystruts.xml");//加载文件Document doc = reader.read(in);//获取根结点Element rootElem = doc.getRootElement();//得到package结点Element ele_package = rootElem.element("package");//获取action结点List<Element> listAction = ele_package.elements("action");//遍历  封装for (Element action : listAction) {ActionMapping actionMapping = new ActionMapping();actionMapping.setName(action.attributeValue("name"));actionMapping.setClassName(action.attributeValue("class"));actionMapping.setMethod(action.attributeValue("method"));//封转结果集Map<String,Result> results = new HashMap<>();//封装结果视图Iterator<Element> it = action.elementIterator();while(it.hasNext()){Element ele_result = it.next();//封装到对象中Result result = new Result();result.setName(ele_result.attributeValue("name"));result.setType(ele_result.attributeValue("type"));result.setPage(ele_result.getTextTrim());System.out.println(result.getName());//添加到Result集合中results.put(result.getName(), result);}//将结果集存入ActionMapping对象中actionMapping.setResults(results);//将actionMapping添加到集合中actions.put(actionMapping.getName(), actionMapping);}} catch (Exception e) {throw new RuntimeException("启动初始化错误",e);}}}

然后写一个业务逻辑层(这里暂时不处理)

package cn.qblank.service;import cn.qblank.dao.UserDao;import cn.qblank.entity.User;public class UserService {private UserDao userDao = new UserDao();/** * 登陆 * @param user * @return */public User login(User user){return userDao.login(user);}}

下面我们就开始写对其进行调度

传统的MVC我们使用Servlet来接收提交的参数，这次我们只用一个总Servlet来控制，其他的用action来操作

我们可以使用一个过滤器对所有的.action为后缀进行拦截，在web.xml中进行配置

<!-- 总的Servlet  总控制器 --><servlet>  <servlet-name>ActionServlet</servlet-name>  <servlet-class>cn.qblank.servlet.ActionServlet</servlet-class>  <load-on-startup>1</load-on-startup></servlet><!-- 总控制器 --><servlet-mapping>  <servlet-name>ActionServlet</servlet-name>  <url-pattern>*.action</url-pattern></servlet-mapping>

然后对应的写一个ActionServlet对各个请求进行相应跳转处理

public class ActionServlet extends HttpServlet {private ActionMappingManager actionMappingManager;@Overridepublic void init() throws ServletException {//创建一个管理类对象，获取封装的xml数据actionMappingManager = new ActionMappingManager();}@Overrideprotected void doGet(HttpServletRequest req, HttpServletResponse resp)throws ServletException, IOException {//http://localhost:8080/mystruts/login.actiontry {//获取请求的UriString uri = req.getRequestURI();//得到loginString actionName = uri.substring(uri.lastIndexOf("/") + 1, uri.lastIndexOf(".action"));//根据action名字获得对应的actionActionMapping actionMapping = actionMappingManager.getActionMapping(actionName);String className = actionMapping.getClassName();//当前请求的方法String method = actionMapping.getMethod();//通过反射获取   反射： 创建对象，调用方法； 获取方法返回的标记Class<?> clazz = Class.forName(className);//构建对象Object obj = clazz.newInstance();Method m = clazz.getDeclaredMethod(method, HttpServletRequest.class,HttpServletResponse.class);//调用方法 拿到标记String flag = (String) m.invoke(obj, req,resp);//测试System.out.println(flag);//通过标记拿到resultResult result = actionMapping.getResults().get(flag);//测试//然后通过result获取对应的跳转类型(type) 跳转页面(page)String type = result.getType();//获取跳转页面String page = result.getPage();//跳转if ("redirect".equals(type)) {resp.sendRedirect(req.getContextPath()+page);}else{req.getRequestDispatcher(page).forward(req, resp);}} catch (Exception e) {e.printStackTrace();}}@Overrideprotected void doPost(HttpServletRequest req, HttpServletResponse resp)throws ServletException, IOException {doGet(req, resp);}}

下面我们就来运行一波

当登陆成功时，直接跳到index.jsp

失败则继续跳回登陆页面

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