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javaweb之浏覽功能

今天我們來寫浏覽功能，浏覽主要是通過sql語句将資料庫裡的資料查出來，并顯示在頁面上。

一.dao層

在上一篇文章的基礎上dao層加入浏覽方法。

public List<Course> list(){
        String sql="select * from submitcourse";
        List<Course> list=new ArrayList<>();
         ResultSet rs=null;
        Course ns=new Course();
        try {
             Connection conn=DBUtil.getConnection();
             PreparedStatement pstmt=conn.prepareStatement(sql);        
            // pstmt.setString(1,n.getTeachername());
             rs=pstmt.executeQuery();
             while(rs.next())
             {
                 ns=new Course(rs.getString(1),rs.getString(2),rs.getString(3));
                 list.add(ns);
             }
             //System.out.println(rs);
             System.out.println(rs);
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return list;
    }

二.Servlet層

在servlet中實作互動，并修改servlet裡面的格式。

package servlet;

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

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

import Bean.Course;
import dao.daoCourse;

/**
 * Servlet implementation class course_servlet
 */
@WebServlet("/course_servlet")
public class course_servlet extends HttpServlet {
    private static final long serialVersionUID = 1L;
       daoCourse gooddao=new daoCourse();//調用dao層的方法
    /**
     * @see HttpServlet#HttpServlet()
     */
    public course_servlet() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        doPost(request, response);
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        request.setCharacterEncoding("utf-8");
        response.setCharacterEncoding("utf-8");
        String method=request.getParameter("method");
        if("add".equals(method))
        {
        String teachername=request.getParameter("teachername");
        String classname=request.getParameter("classname");
        String place=request.getParameter("place");
        Course n=new Course(classname,teachername,place);
        gooddao.add(n);
        request.setAttribute("message", "添加成功");
        request.getRequestDispatcher("NewFile2.jsp").forward(request, response);
        }
        }
        else if("looklist".equals(method)) {            
            List<Course> nt= gooddao.list();
            request.setAttribute("nt", nt);
            System.out.println("王建民");
            request.getRequestDispatcher("NewFile3.jsp").forward(request, response);
        }
    
    }

}

三.寫jsp

 在此處我們使用jstl和EL來進行資料的擷取

NewFile3.jsp：

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
    <%@taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<table>
<tr>
<td>課程名稱</td>
<td>教師姓名</td>
<td>教學地點</td>
<td>操作</td>
</tr>
 <c:forEach items="${nt}" var="xm">
            <tr>
                <td>${xm.classname}</td>
                <td>${xm.teachername}</td>
                <td>${xm.place}</td>
               <td><a href="course_servlet?method=delete&teachername=${xm.teachername}" onClick="return confirm('确認删除嗎？');">删除</a>
                   <a href="course_servlet?method=queryByTeachername&teachername=${xm.teachername}">修改</a>
            </tr>
        </c:forEach>
</table>
</body>
</html>

 NewFile2.jsp：

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<%
    Object message = request.getAttribute("message");
    if(message!=null && !"".equals(message)){

%>
<script type="text/javascript">
    alert("<%=request.getAttribute("message")%>");
</script>
<%} %>
<form action="course_servlet?method=looklist" method="post" >
<h1>添加成功</h1>
<input type="submit" value="浏覽">
</form>
</body>
</html>

四.運作結果：

javaweb之浏覽功能

這寫的有點醜，可以做一個菜單。

javaweb之浏覽功能

 點選浏覽即可浏覽出表裡面的資料。

下一篇文章為大家寫删除功能！！！！！！

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