Struts框架核心技术小小班

? 简介
? Web 开发基础
–B/S结构程序
–请求响应机制
–HTML
–Servlet
–JSP
–Web 服务器
? 编程思想
–分层开发思想
–面向接口编程思想
? 设计模式
–DAO设计模式
–MVC设计模式

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? 简介
–因为Struts是Servlet+JSP的MVC解决方案，所以在学习Struts之前有必要了解如下Web开发的基础知识，使用Servlet+JSP如何编程，以及编程思想和设计模式中Web开发中应用
? 这对我们在学习Struts时是很有帮助的
? 我们要比较Servlet+JSP程序的MVC模式实现和Struts MVC的异同
? Servlet+JSP程序的弊端
? Struts的优势
? 程序开发的思想
? 设计模式的应用

? Web 开发基础
– B/S结构程序
? B/S结果程序是指，基于Browser（浏览器）/Server（服务器）的应用程序
? 相对C/S结构程序而言，B/S结构程序有如下优点：
– 基于网络
– 共享性好
– 客户端零维护
– 请求响应机制
? B/S程序的主要特征是请求（request）响应（response）机制
? 通常使用的协议是Http协议，该协议是无状态的
– HTML
? HTML的全称是Hyper Text Markup Language（超文本标记语言）
?基本结构是：


\r\n");    
            out.write("        \r\n");    
            out.write("\t\r\n");    
            out.write("\t\r\n");    
            out.write("\t        \r\n");    
            out.write("\t\r\n");    
            out.write("\t\r\n");    
            out.write("\t\r\n");    
            out.write("\r\n");    
            out.write("    \r\n");    
            out.write("    \r\n");    
            out.write("    \r\n");    
            out.write("        This is my JSP page.
\r\n");    
            out.write("    \r\n");    
            out.write("\r\n");    
        } catch (Throwable t) {    
            if (!(t instanceof SkipPageException)){    
                out = _jspx_out;    
                if (out != null && out.getBufferSize() != 0)    
                    try { out.clearBuffer(); } catch (java.io.IOException e) {}    
                if (_jspx_page_context != null) _jspx_page_context.handlePageException(t);    
            }    
        } finally {    
            _jspxFactory.releasePageContext(_jspx_page_context);    
        }    
    }    
}

– Web 服务器
? Web工程的运行容器，如Tomcat

? 编程思想
–分层开发思想
? 软件的层次结构可以分为四层：
–表现层
–控制层
–业务逻辑层
–数据逻辑层（持久层）
–面向接口编程思想
? 在编程中将业务逻辑抽象出接口，以供上次调用
? 依赖抽象（接口），而非具体（接口实现）的编程思想，又称之为控制反转（Inversion of Control)

 

? 设计模式
–DAO设计模式
? DAO设计模式
–DAO的全称是：Data Access Object，数据访问对象。
–使用DAO设计模式，来封装数据库持久层的所有操作（CRUD），使低级的数据逻辑和高级的业务逻辑分离，达到解耦合的目的。
? 一个典型的DAO实现有如下的组件：
–一个 DAO 接口
–一个实现了 DAO 接口的具体类
–一个 DAO 工厂类
–数据传输对象(有时称为值对象)
?以维护一个客户信息为例，具体组件如下所示：
–CustomerDao 接口
–Customer 值对象（VO)
–CustomerDaoImpl（接口的具体实现类）
–CustomerFactory（工厂类，实例化用）

–MVC设计模式
? MVC的全称是：Model(模型) View(视图) Controller( 控制器)
? Model
–对应业务逻辑层、数据逻辑层
–由接口及其实现类充当
? View
–对应表现层
–由HTML页面、JSP页面、Tag（标签）等充当
? Controller
–对应控制层
–由Servlet 或Struts中的Action等充当

 

? 编程思想和设计模式的具体应用
–图示

自定义MVC

 

?实例
–以添加客户和查询客户列表为例来说明上述内容
–程序运行结果

数据库设置 

CustomerDao.java

 

CustomerDaoImpl.java

package com.redking.dao.impl;    

import java.sql.Connection;    
import java.sql.PreparedStatement;    
import java.sql.ResultSet;    
import java.sql.SQLException;    
import java.sql.Statement;    
import java.util.ArrayList;    
import java.util.List;    

import com.redking.dao.CustomerDao;    
import com.redking.util.ConnectionUtil;    
import com.redking.util.SQLConstants;    
import com.redking.vo.Customer;    

public class CustomerDaoImpl implements CustomerDao,SQLConstants{    

         public List listCustomer() {    
                ConnectionUtil cu = new ConnectionUtil();    
                Connection conn = cu.getConnection();    
                 //conn.setAutoCommit(false);设置默认不自动提交    
                 //Statement stmt;静态添加    
                 //PrepareStatement pstmt;动态添加    
                List list = new ArrayList();    
                 try {    
                        Statement stmt = conn.createStatement();    
                        ResultSet rs = stmt.executeQuery(QUERY_CUSTOMER_SQL);    
                         while(rs.next()){    
                                 int id = rs.getInt(1);    
                                String name = rs.getString(2);    
                                String email = rs.getString(3);    
                                Customer c = new Customer();    
                                c.setId(id);    
                                c.setName(name);    
                                c.setEmail(email);    
                                list.add(c);    
                        }    
                         return list;    
                } catch (SQLException e) {    
                        e.printStackTrace();    
                } finally{    
                         try {    
                                conn.close();    
                        } catch (SQLException e) {    
                                e.printStackTrace();    
                        }    
                }    
                 return null;    
        }    

         public void save(Customer c) {    
                ConnectionUtil cu = new ConnectionUtil();    
                Connection conn = cu.getConnection();    
                 //conn.setAutoCommit(false);设置默认不自动提交    
                 //Statement stmt;静态添加    
                 //PrepareStatement pstmt;动态添加    
                PreparedStatement pstmt = null;    
                 try {    
                        pstmt = conn.prepareStatement(ADD_CUSTOMER_SQL);    
                        pstmt.setString(1, c.getName());    
                        pstmt.setString(2, c.getEmail());    
                        pstmt.executeUpdate();    
                         //conn.commit();设置强制提交    
                } catch (SQLException e) {    
                        e.printStackTrace();    
                } finally{    
                         try {    
                                conn.close();    
                        } catch (SQLException e) {    
                                e.printStackTrace();    
                        }    
                }    
        }    

}

CustomerServlet.java

package com.redking.servlet;    

import java.io.IOException;    
import java.io.PrintWriter;    
import java.util.List;    

import javax.servlet.ServletException;    
import javax.servlet.http.HttpServlet;    
import javax.servlet.http.HttpServletRequest;    
import javax.servlet.http.HttpServletResponse;    

import com.redking.dao.CustomerDao;    
import com.redking.dao.impl.CustomerDaoImpl;    
import com.redking.vo.Customer;    

public class CustomerServlet extends HttpServlet {    

         /**    
         * Constructor of the object.    
         */    
         public CustomerServlet() {    
                 super();    
        }    

         /**    
         * Destruction of the servlet.
    
         */    
         public void destroy() {    
                 super.destroy(); // Just puts "destroy" string in log    
                 // Put your code here    
        }    

         /**    
         * The doGet method of the servlet.
    
         *    
         * This method is called when a form has its tag value method equals to get.    
         *    
         * @param request the request send by the client to the server    
         * @param response the response send by the server to the client    
         * @throws ServletException if an error occurred    
         * @throws IOException if an error occurred    
         */    
         public void doGet(HttpServletRequest request, HttpServletResponse response)    
                         throws ServletException, IOException {    
                doPost(request,response);    
        }    

         /**    
         * The doPost method of the servlet.
    
         *    
         * This method is called when a form has its tag value method equals to post.    
         *    
         * @param request the request send by the client to the server    
         * @param response the response send by the server to the client    
         * @throws ServletException if an error occurred    
         * @throws IOException if an error occurred    
         */    
         public void doPost(HttpServletRequest request, HttpServletResponse response)    
                         throws ServletException, IOException {    
                 /*    
                //响应用户请求    
                String name = request.getParameter("name");    
                String email = request.getParameter("email");    
                //调用后台逻辑-dao    
                CustomerDao dao = new CustomerDaoImpl();    
                Customer c = new Customer();    
                c.setName(name);    
                c.setEmail(email);    
                dao.save(c);    
                //跳转其他页面    
                //RequestDispatcher    
                request.getRequestDispatcher("/pages/Customer.jsp").forward(request,response);    
                */    
                String methodName = request.getParameter( "methodName");    
                 if(methodName!= null&&methodName.equals( "save")){    
                        save(request,response);    
                } else{    
                        list(request,response);    
                }    
        }    
         public void save(HttpServletRequest request, HttpServletResponse response)    
         throws ServletException, IOException {    

                 //响应用户请求    
                String name = request.getParameter( "name");    
                String email = request.getParameter( "email");    
                 //调用后台逻辑-dao    
                CustomerDao dao = new CustomerDaoImpl();    
                Customer c = new Customer();    
                c.setName(name);    
                c.setEmail(email);    
                dao.save(c);    
                 //跳转其他页面    
                 //RequestDispatcher    
                 //request.getRequestDispatcher("/pages/Customer.jsp").forward(request,response);    
                list(request,response);    
        }    
         public void list(HttpServletRequest request, HttpServletResponse response)    
         throws ServletException, IOException {    

                 //响应用户请求    
                String name = request.getParameter( "name");    
                String email = request.getParameter( "email");    
                 //调用后台逻辑-dao    
                CustomerDao dao = new CustomerDaoImpl();    
                List list = dao.listCustomer();    
                request.setAttribute( "CustomerList", list);    
                 //跳转其他页面    
                 //RequestDispatcher    
                request.getRequestDispatcher( "/pages/Customer.jsp").forward(request,response);    
        }    

         /**    
         * Initialization of the servlet.
    
         *    
         * @throws ServletException if an error occurs    
         */    
         public void init() throws ServletException {    
                 // Put your code here    
        }    

}

ConnectionUtilTest.java

CustomerDaoImplTest.java

ConnectionUtil.java

  SQLConstants.java

Customer.java

DBConfig.properties

Customer.jsp

 

<%@ page language= "java" import= "java.util.*,com.redking.vo.*" pageEncoding= "gbk"%>    
<%@ taglib uri= "http://java.sun.com/jsp/jstl/core" prefix="redking" %>    
<%    
String path = request.getContextPath();    
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";    
%>    

"-//W3C//DTD HTML 4.01 Transitional//EN">    
    
        
        "<%=basePath%>">    
            
        "pragma" content="no-cache">    
        "cache-control" content="no-cache">    
        "expires" content="0">        
        "keywords" content="keyword1,keyword2,keyword3">    
        "description" content="This is my page">    
            

        
        
        

"f1" id="f1" action="<%=path %>/servlet/CustomerServlet?methodName=save" method="post">    
            "0">    
                    
                        
                        
                    
                    
                        
                        
                    
                    
                        
                    
            

Name:	"text" name="name" >
Email:	"text" name="email" >
"2" align="center">"submit" value="保存">

    
        

    
        

---

    
            
            
        <%--    
        <%    
                List list = (List) request.getAttribute("CustomerList");    
                //遍列LIST    
                for(int i=0;i                        Customer c = (Customer) list.get(i);    
                        out.println("");    
                        out.println("");    
                        out.println("");    
                        out.println("");    
                        out.println("");    
                }    
         %>    
            --%>    
            <%--使用标准标签 --%>    
            "c" items="${CustomerList}">    
                        
                                
                                
                                
                        
                
        

ID	Name	Email
");                             out.println(c.getId());                             out.println("	");                             out.println(c.getName());                             out.println("	");                             out.println(c.getEmail());                             out.println("
${c.id }	${c.name }	${c.email }

    
        

测试：

 

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