Struts框架核心技術小小班

? 簡介
? Web 開發基礎
–B/S結構程序
–請求響應機制
–HTML
–Servlet
–JSP
–Web 服務器
? 編程思想
–分層開發思想
–面向接口編程思想
? 設計模式
–DAO設計模式
–MVC設計模式

----------------------------Start---------------------------------------

? 簡介
–因爲Struts是Servlet+JSP的MVC解決方案，所以在學習Struts之前有必要了解如下Web開發的基礎知識，使用Servlet+JSP如何編程，以及編程思想和設計模式中Web開發中應用
? 這對我們在學習Struts時是很有幫助的
? 我們要比較Servlet+JSP程序的MVC模式實現和Struts MVC的異同
? Servlet+JSP程序的弊端
? Struts的優勢
? 程序開發的思想
? 設計模式的應用

? Web 開發基礎
– B/S結構程序
? B/S結果程序是指，基於Browser（瀏覽器）/Server（服務器）的應用程序
? 相對C/S結構程序而言，B/S結構程序有如下優點：
– 基於網絡
– 共享性好
– 客戶端零維護
– 請求響應機制
? B/S程序的主要特徵是請求（request）響應（response）機制
? 通常使用的協議是Http協議，該協議是無狀態的
– HTML
? HTML的全稱是Hyper Text Markup Language（超文本標記語言）
?基本結構是：
<HTML>
<HEAD>
<title>, <base>, <link>, <meta>
</HEAD>
<BODY>
HTML 文件的正文寫在這裏... ...
</BODY>
</HTML>
– Servlet
? Servlet 是爲動態創建Web工程而提供的編程接口
MyServlet.java

web.xml

設置servlet的申明和映射

測試：

– JSP
? 爲了解決Servlet的開發效率問題而設計的開發語言
? 底層執行還是Servlet

MyJsp_jsp.java

package org.apache.jsp;

import javax.servlet.*;
import javax.servlet.http.*;
import javax.servlet.jsp.*;
import java.util.*;

public final class MyJsp_jsp extends org.apache.jasper.runtime.HttpJspBase
        implements org.apache.jasper.runtime.JspSourceDependent {

    private static final JspFactory _jspxFactory = JspFactory.getDefaultFactory();

    private static java.util.List _jspx_dependants;

    private javax.el.ExpressionFactory _el_expressionfactory;
    private org.apache.AnnotationProcessor _jsp_annotationprocessor;

    public Object getDependants() {
        return _jspx_dependants;
    }

    public void _jspInit() {
        _el_expressionfactory = _jspxFactory.getJspApplicationContext(getServletConfig().getServletContext()).getExpressionFactory();
        _jsp_annotationprocessor = (org.apache.AnnotationProcessor) getServletConfig().getServletContext().getAttribute(org.apache.AnnotationProcessor.class.getName());
    }

    public void _jspDestroy() {
    }

    public void _jspService(HttpServletRequest request, HttpServletResponse response)
                throws java.io.IOException, ServletException {

        PageContext pageContext = null;
        HttpSession session = null;
        ServletContext application = null;
        ServletConfig config = null;
        JspWriter out = null;
        Object page = this;
        JspWriter _jspx_out = null;
        PageContext _jspx_page_context = null;

        try {
            response.setContentType("text/html;charset=ISO-8859-1");
            pageContext = _jspxFactory.getPageContext(this, request, response,
                                    null, true, 8192, true);
            _jspx_page_context = pageContext;
            application = pageContext.getServletContext();
            config = pageContext.getServletConfig();
            session = pageContext.getSession();
            out = pageContext.getOut();
            _jspx_out = out;

            out.write('\r');
            out.write('\n');

String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";

            out.write("\r\n");
            out.write("\r\n");
            out.write("<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\">\r\n");
            out.write("<html>\r\n");
            out.write("    <head>\r\n");
            out.write("        <base href=\"");
            out.print(basePath);
            out.write("\">\r\n");
            out.write("        \r\n");
            out.write("        <title>My JSP 'MyJsp.jsp' starting page</title>\r\n");
            out.write("        \r\n");
            out.write("\t<meta http-equiv=\"pragma\" content=\"no-cache\">\r\n");
            out.write("\t<meta http-equiv=\"cache-control\" content=\"no-cache\">\r\n");
            out.write("\t<meta http-equiv=\"expires\" content=\"0\">        \r\n");
            out.write("\t<meta http-equiv=\"keywords\" content=\"keyword1,keyword2,keyword3\">\r\n");
            out.write("\t<meta http-equiv=\"description\" content=\"This is my page\">\r\n");
            out.write("\t\r\n");
            out.write("\r\n");
            out.write("    </head>\r\n");
            out.write("    \r\n");
            out.write("    <body>\r\n");
            out.write("        This is my JSP page. <br>\r\n");
            out.write("    </body>\r\n");
            out.write("</html>\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 服務器
? Web工程的運行容器，如Tomcat

? 編程思想
–分層開發思想
? 軟件的層次結構可以分爲四層：
–表現層
–控制層
–業務邏輯層
–數據邏輯層（持久層）
–面向接口編程思想
? 在編程中將業務邏輯抽象出接口，以供上次調用
? 依賴抽象（接口），而非具體（接口實現）的編程思想，又稱之爲控制反轉（Inversion of Control)

? 設計模式
–DAO設計模式
? DAO設計模式
–DAO的全稱是：Data Access Object，數據訪問對象。
–使用DAO設計模式，來封裝數據庫持久層的所有操作（CRUD），使低級的數據邏輯和高級的業務邏輯分離，達到解耦合的目的。
? 一個典型的DAO實現有如下的組件：
–一個 DAO 接口
–一個實現了 DAO 接口的具體類
–一個 DAO 工廠類
–數據傳輸對象(有時稱爲值對象)
?以維護一個客戶信息爲例，具體組件如下所示：
–CustomerDao 接口
–Customer 值對象（VO)
–CustomerDaoImpl（接口的具體實現類）
–CustomerFactory（工廠類，實例化用）

–MVC設計模式
? MVC的全稱是：Model(模型) View(視圖) Controller( 控制器)
? Model
–對應業務邏輯層、數據邏輯層
–由接口及其實現類充當
? View
–對應表現層
–由HTML頁面、JSP頁面、Tag（標籤）等充當
? Controller
–對應控制層
–由Servlet 或Struts中的Action等充當

? 編程思想和設計模式的具體應用
–圖示

自定義MVC

?實例
–以添加客戶和查詢客戶列表爲例來說明上述內容
–程序運行結果

數據庫設置

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);設置默認不自動提交
                //Statement stmt;靜態添加
                //PrepareStatement pstmt;動態添加
                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);設置默認不自動提交
                //Statement stmt;靜態添加
                //PrepareStatement pstmt;動態添加
                PreparedStatement pstmt = null;
                try {
                        pstmt = conn.prepareStatement(ADD_CUSTOMER_SQL);
                        pstmt.setString(1, c.getName());
                        pstmt.setString(2, c.getEmail());
                        pstmt.executeUpdate();
                        //conn.commit();設置強制提交
                } 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. <br>
         */
        public void destroy() {
                super.destroy(); // Just puts "destroy" string in log
                // Put your code here
        }

        /**
         * The doGet method of the servlet. <br>
         *
         * 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. <br>
         *
         * 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 {
                /*
                //響應用戶請求
                String name = request.getParameter("name");
                String email = request.getParameter("email");
                //調用後臺邏輯-dao
                CustomerDao dao = new CustomerDaoImpl();
                Customer c = new Customer();
                c.setName(name);
                c.setEmail(email);
                dao.save(c);
                //跳轉其他頁面
                //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 {

                //響應用戶請求
                String name = request.getParameter("name");
                String email = request.getParameter("email");
                //調用後臺邏輯-dao
                CustomerDao dao = new CustomerDaoImpl();
                Customer c = new Customer();
                c.setName(name);
                c.setEmail(email);
                dao.save(c);
                //跳轉其他頁面
                //RequestDispatcher
                //request.getRequestDispatcher("/pages/Customer.jsp").forward(request,response);
                list(request,response);
        }
        public void list(HttpServletRequest request, HttpServletResponse response)
        throws ServletException, IOException {

                //響應用戶請求
                String name = request.getParameter("name");
                String email = request.getParameter("email");
                //調用後臺邏輯-dao
                CustomerDao dao = new CustomerDaoImpl();
                List list = dao.listCustomer();
                request.setAttribute("CustomerList", list);
                //跳轉其他頁面
                //RequestDispatcher
                request.getRequestDispatcher("/pages/Customer.jsp").forward(request,response);
        }

        /**
         * Initialization of the servlet. <br>
         *
         * @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+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
    <head>
        <base href="<%=basePath%>">
        <title>My JSP 'Customer.jsp' starting page</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 name="f1" id="f1" action="<%=path %>/servlet/CustomerServlet?methodName=save" method="post">
            <table border="0">
                <tr>
                    <td>Name:</td>
                    <td><input type="text" name="name" ></td>
                </tr>
                <tr>
                    <td>Email:</td>
                    <td><input type="text" name="email" ></td>
                </tr>
                <tr>
                    <td colspan="2" align="center"><input type="submit" value="保存"></td>
                </tr>
            </table>
        </form>
        <hr>
        <table>
        <tr><th>ID</th><th>Name</th><th>Email</th></tr>
        <%--
        <%
                List list = (List) request.getAttribute("CustomerList");
                //遍列LIST
                for(int i=0;i<list.size();i++){
                        Customer c = (Customer) list.get(i);
                        out.println("<tr>");
                        out.println("<td>");
                        out.println(c.getId());
                        out.println("</td>");
                        out.println("<td>");
                        out.println(c.getName());
                        out.println("</td>");
                        out.println("<td>");
                        out.println(c.getEmail());
                        out.println("</td>");
                        out.println("</tr>");
                }
         %>
            --%>
            <%--使用標準標籤 --%>
            <redking:forEach var="c" items="${CustomerList}">
                    <tr>
                            <td>
                                    ${c.id }
                            </td>
                            <td>
                                    ${c.name }
                            </td>
                            <td>
                                    ${c.email }
                            </td>
                    </tr>
            </redking:forEach>
        </table>
    </body>
</html>

測試：

----------------------------------END-------------------------------------

Struts框架核心技術小小班

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