jsp+servlet+javabean实现ssh的mvc模式
干了很久的项目都是使用SSH框架的,现在团队有位搞美工的美女突然想要搞java了,让我做下指导并打个基本的框架,需要使用最基本的架构,这样说来那SSH只能滚得远远的了;
最基本的架构也就jsp+servlet+javabean,但心里感觉还是不爽,搞这个不是纯属浪费时间啊。后来一想,对了我自己可以不用框架来设计出一个简单的mvc架构来实现框架带来的分层效果:
这里我就以登录为例子来讲解下,讲解的顺序为v--->c---->m
页面端:login.html
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <title>amdinLogin.html</title> </head> <body> <form action="../AdminLogin.action" method="post"> <input type = "text" name = "username"/> <input type = "password" name = "password"/> <input type = "submit" name = "login" value = "注册"/> </form> </body> </html>
配置文件web.xml
<servlet> <servlet-name>controlServlet</servlet-name> <servlet-class>xidian.sl.equipment.Servlet.ControlServlet</servlet-class> <!-- 这里的配置与一般的servlet一样,但由于整个项目只会有一个servlet,所有的访问都将访问这个servlet,因此不同的访问只需要添加下面的参数即可--> <init-param> <!-- 页面请求的地址--> <param-name>AdminLogin</param-name> <!-- 处理action的后台Action地址--> <param-value>xidian.sl.equipment.action.LoginAction</param-value> </init-param> <init-param> <param-name>picListAction</param-name> <param-value>xidian.sl.equipment.action.PicListAction</param-value> </init-param> <init-param> <param-name>newListAction</param-name> <param-value>xidian.sl.equipment.action.NewListAction</param-value> </init-param> </servlet> <servlet-mapping> <servlet-name>controlServlet</servlet-name> <url-pattern>*.action</url-pattern> </servlet-mapping>
充当控制层的servlet:xidian.sl.equipment.Servlet.ControlServlet(很重要)
package xidian.sl.equipment.Servlet; import java.io.IOException; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import xidian.sl.equipment.action.interfaces.Action; import xidian.sl.equipment.actionfactory.ActionFactory; public class ControlServlet extends HttpServlet{ /** * 任何请求都会到这个servlet中,这个servlet就是充当MVC模式中的C(控制层) */ private static final long serialVersionUID = 1L; @Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doPost(request, response); } @Override protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { /** * 得到当前Servlet的请求路径 * */ String pathName = request.getServletPath(); //System.out.println("pathName:"+pathName); /** * 得到请求的Action名字 * */ int index = pathName.indexOf("."); String ActionName = pathName.substring(1, index); //System.out.println(ActionName); /** * 获取运行时参数 * */ String ActionClassName = this.getInitParameter(ActionName); //System.out.println("actionclassName "+ ActionClassName); /** * 得到Action对象 * */ Action action = ActionFactory.getActionFactory().getAction(ActionClassName); //System.out.println("action "+action); /** * 执行Action的execute得到要返回的URL路径 * */ String url = action.execute(request, response); if(url == null){ request.getRequestDispatcher("error.jsp").forward(request, response); }else{ request.getRequestDispatcher(url).forward(request, response); } } }
Action:面向接口编程,提供一个统一的Action接口,里面就一个方法execute();模拟struts1.x
package xidian.sl.equipment.action.interfaces; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; public interface Action { /** * 所有的具体Action实现这个接口 * @param request 请求对象 * @param response 应答对象 * @return :结果页面 */ public String execute(HttpServletRequest request, HttpServletResponse response); }
LoginAction:
package xidian.sl.equipment.action; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import xidian.sl.equipment.action.interfaces.Action; import xidian.sl.equipment.dao.impl.AdminDAOImpl; import xidian.sl.equipment.dao.interfaces.AdminDAO; public class LoginAction implements Action { @Override public String execute(HttpServletRequest request, HttpServletResponse response) { /** * 从request中得到相应的值 * */ String username = request.getParameter("username"); String password = request.getParameter("password"); /** * 实例化DAO层,但其实这样做还是不完美的,最好自己写一个依赖注入的类 * */ AdminDAO adminDAO = new AdminDAOImpl(); /** * 返回查找后的二维数组 * */ String[][] data = adminDAO.findAdmin(username, password); if(data == null|| (data != null&& data.length == 0)){ //数组为空,表示无此账号存在 return "admin/login.html"; } else { return "admin/index.html"; } } }
在实现类LoginAction中实例化了AdminDAO进行持久化操作,这里为了方便起见是直接使用new进行实例化,但这样硬编码带来耦合,如需要改进可以参考模拟spring的ioc
http://www.cnblogs.com/shenliang123/archive/2012/05/10/2494412.html 讨论简单工厂模式时有简单的实现,大家可以进行改进使其更加完美
AdminDAO:
package xidian.sl.equipment.dao.interfaces; public interface AdminDAO { /** * 根据用户名与密码来查找相应用户 * */ public String[][] findAdmin(String username, String password); }
AdminDAOImpl:
package xidian.sl.equipment.dao.impl; import xidian.sl.equipment.dao.interfaces.AdminDAO; import xidian.sl.equipment.util.DbConn; public class AdminDAOImpl implements AdminDAO{ @Override public String[][] findAdmin(String username, String password) { String sql = "select * from admin as ad where ad.aId = '"+username+"' and ad.aPassword = '"+password+"'"; String[][] data = DbConn.query(sql); return data; } }
该实现类中使用了已封装好的数据库操作类,详细见:http://www.cnblogs.com/shenliang123/archive/2012/05/10/2494874.html
数据库的设计比较简单:只需要主键id, 用户账号:username, 账号密码:password
这样就基本实现了mvc的效果,你还可以根据项目的复杂程度向DAO与Action之间再插入一层Service