JavaEE_JSP_完整的JSTL+EL表示式將資料顯示出來的流程
阿新 • • 發佈：2019-01-09
總共分為五個部分，
1.EL+JSTL前端JSP頁面
2.servlet(傳遞資料)
3.dao(操作資料庫)
4.javaBean(ORM)
5.資料庫表設計
1.EL+JSTL前端JSP頁面
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%> <%-- page import="com.user.bean.VimUserInformationObject" --%> <%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %> <% 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>使用者許可權管理</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> <div> <span style="color:red;font-weight:bold"> <% if(session.getAttribute("login_user")!=null){ out.println("尊敬的"+session.getAttribute("login_user")+"<br/>"); } %> </span> </div> <div> <a href="user/normal/servlet/loginOutUser">-登出-</a> <a href="jsp/user/modify_password.jsp">-修改密碼-</a> </div> <div> <div> <span style="color:red;font-weight:bold"> <% if(request.getAttribute("tips")!=null){ out.println(request.getAttribute("tips")+"<br/>"); } %> </span> </div> <form method="post" action=""> <table> <tr> <td>序號</td> <td>使用者名稱</td> <td>許可權</td> </tr> <c:forEach items="${allUserAuthority}" var="item" varStatus="current"> <tr> <td>${current.index}</td> <td>${item.user_name}</td> <td>${item.authority}</td> </tr> </c:forEach> <!-- ${item['user_name']} ${item['authority']} --> <!-- <tr> <td>1</td> <td>szh</td> <td><input name="username" type="checkbox"/></td> <td><input type="checkbox"/></td> </tr> --> </table> <!-- <input type="submit" value="確認刪除" onclick="return confirm('確認刪除?');"/> <input type="reset" value="重選"> --> </form> </div> </body> </html>
2.servlet
package com.user.manage.servlet; import java.util.List; import javax.servlet.RequestDispatcher; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import com.user.bean.VimUserInformationObject; import com.user.dao.MultUserInformationDao; public class ManagerUserAuthorityServlet extends HttpServlet { private static final long serialVersionUID = 1L; /** * Constructor of the object. */ public ManagerUserAuthorityServlet() { super(); } /** * Destruction of the servlet. <br> */ public void destroy() { super.destroy(); // Just puts "destroy" string in log // Put your code here } /** * Initialization of the servlet. <br> * * @throws ServletException * if an error occurs */ public void init() throws ServletException { // Put your code here } // 響應客戶端請求的方法 public void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, java.io.IOException { String tips = ""; // Servlet本身並不輸出響應到客戶端，因此必須將請求轉發到檢視頁面 RequestDispatcher rd; try { MultUserInformationDao userInformationDao = new MultUserInformationDao(); // 暫時將所有使用者的資料放到登入Servlet處理，之後進行優化 List<VimUserInformationObject> allUserAuthorityObjects = userInformationDao .query(); request.setAttribute("allUserAuthority", allUserAuthorityObjects); // // // 獲取轉發物件 rd = request .getRequestDispatcher("/WEB-INF/jsp/user/manager_authority.jsp"); rd.forward(request, response); } catch (Exception e) { e.printStackTrace(); } } }
3.dao(操作資料庫)
package com.user.dao; import java.sql.Connection; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; import java.util.ArrayList; import java.util.List; import com.base.dao.BaseDao; import com.user.bean.VimUserInformationObject; import com.util.DBconnect; //字首mult 表示多表聯查 public class MultUserInformationDao extends BaseDao { public MultUserInformationDao() { super(); } public List<VimUserInformationObject> query() throws Exception { List<VimUserInformationObject> userInformationList = new ArrayList<>(); Connection conn = null; PreparedStatement ps = null; // 建立PreparedStatement 物件 ResultSet rs = null; String sql = new String( "SELECT u.user_id, u.user_name, a.authority FROM user AS u, user_authority as A" + " WHERE a.user_id = u.user_id" + " ORDER BY u.user_id"); try { conn = DBconnect.getConnection(); ps = conn.prepareStatement(sql); rs = ps.executeQuery(); while (rs.next()) { VimUserInformationObject userInformationObject = new VimUserInformationObject( rs.getInt("user_id"), rs.getString("user_name"), rs.getInt("authority")); userInformationList.add(userInformationObject); } } catch (SQLException e) { e.printStackTrace(); } finally { DBconnect.closeAllConnection(rs, ps, conn); } return userInformationList; } public static void main(String[] args) { MultUserInformationDao dao = new MultUserInformationDao(); try { List<VimUserInformationObject> userInformationList = (ArrayList<VimUserInformationObject>) dao .query(); if (!userInformationList.isEmpty()) { for (VimUserInformationObject tmp : userInformationList) { System.out.println("使用者ID:" + tmp.getUser_id() + " 使用者name:" + tmp.getUser_name() + " 使用者許可權:" + tmp.getAuthority()); } } } catch (Exception e) { e.printStackTrace(); } } }
4.javaBean(ORM)
package com.user.bean;
//對應User表 和 User_authority 聯查出來的資料, 字首vim表示虛擬化
public class VimUserInformationObject {
private Integer user_id;
private String user_name;
private Integer authority;
{
user_id = 0;
user_name = "";
authority = 0;
}
public Integer getUser_id() {
return user_id;
}
public void setUser_id(Integer user_id) {
this.user_id = user_id;
}
public String getUser_name() {
return user_name;
}
public void setUser_name(String user_name) {
this.user_name = user_name;
}
public Integer getAuthority() {
return authority;
}
public void setAuthority(Integer authority) {
this.authority = authority;
}
public VimUserInformationObject(Integer user_id, String user_name,
Integer authority) {
super();
this.user_id = user_id;
this.user_name = user_name;
this.authority = authority;
}
public static void main(String[] args) {
// TODO Auto-generated method stub
}
}
最終顯示結果
