Question

这是我第一次问如此我很抱歉，如果我搞砸了。哦，所以在这里它

我有这个mysql表，我想在jsp页面中显示，我实际上让它工作，但它不是一个很好的方法，因为所有代码（连接到数据库等）都在JSP.So我做一个java bean，它控制连接到数据库并执行sql查询部分，以及一个单独的JSP页面，我可以在其中显示该表。

main.jsp中

<%@ page import="java.sql.*" %>
<?xml version='1.0' encoding='UTF-8' ?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"
      xmlns:h="http://java.sun.com/jsf/html">


<head>
<title>Welcome to Car Rental System</title>
<link rel="stylesheet" href="//code.jquery.com/ui/1.11.1/themes/smoothness/jquery-ui.css"></link>
<script src="//ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="//code.jquery.com/ui/1.11.1/jquery-ui.js"></script>
<script src="jquery.backstretch.min.js"></script>
<link rel="stylesheet" href="style.css"></link>
<link href="https://fonts.googleapis.com/css?family=Source+Sans+Pro" rel="stylesheet"> 



</head>

    <body>

        <p><div><center><h1><b>Car Rental System</b></h1></center></div></p>  

         <% 

<jsp:useBean id="displayCarList" class="displayCarList.displayCarList" >
<jsp:setProperty name="displayCarList" property="*"/>
</jsp:useBean>        
     <%
     String carbookId = request.getParameter("carbookId");
     String manufacturername = request.getParameter("manufacturername");
     String modelname = request.getParameter("modelname");
     String price_day = request.getParameter("price_day");
     %>

     <table border='3' align='center'>
         <tr>
         <td><b>Car ID</td>
         <td><b>Manufacturer</td>
         <td><b>Model name</td>
         <td><b>Price per day</td>
         </tr>



<tr>
<td><%=displayCarList.getCarbookid()%></td>
<td><%=displayCarList.getManufacturername()%></td>     
<td><%=displayCarList.getModelname()%></td>
<td><%=displayCarList.getPriceday()%></td>
</tr> 
</table>
<br></br>

<form action=secondpage.jsp method="post">
<fieldset><legend>Fill in the form below :</legend>

<p><b>Name:</b> <input type="text" name="name" size="20" maxlength="40" /></p>
<p><b>Telephone number</b> <input type="text" name="phonenumber" th:field="*{phonenumber}" size="20" maxlength="40" /></p>
<p><b>Rental date:</b> <input type="date" th:field="*{rentaldate}"  name="rentaldate"></p>
<p><b>Return date:</b> <input type="date" th:field="*{returndate}" name="returndate"></p>
<p><b>Car ID:</b> <input type="text" name="carID" th:field="*{carID}" size="20" maxlength="40" /></p>

<div align="left"><input type="submit" name="submit" value="Submit " /></div>

</form>
     <script>

$.backstretch("background2.jpg");
</script>
    </body>
</html>

以下是java bean，displayCarList.java

package displayCarList;

import java.io.*;
import static java.lang.System.out;
import java.util.*;
import javax.sql.*;
import javax.servlet.*;
import javax.servlet.http.*;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.logging.Level;
import java.util.logging.Logger;


public class displayCarList {

  private String carbookId, manufacturername, modelname, price_day;

  Connection con = null;  
  Statement stmt = null;
  ResultSet rs = null;

    public displayCarList(){

  try {
      try {
          Class.forName("com.mysql.jdbc.Driver");
      } catch (ClassNotFoundException ex) {
          Logger.getLogger(displayCarList.class.getName()).log(Level.SEVERE, null, ex);
      }
  con =DriverManager.getConnection ("jdbc:mysql://localhost:3306/rentalcar","root","");
  stmt = con.createStatement();
  rs = stmt.executeQuery("SELECT * FROM carlist");
  while(rs.next()){
       carbookId = rs.getString(1);
       manufacturername= rs.getString(2);
        modelname = rs.getString(3);
        price_day = rs.getString(4);
        }
stmt.close();
con.close();
  // displaying record
  } catch (SQLException e) {
 System.out.println("couldnotconnecYO");
    }
    }
public String getCarbookid(){
    return carbookId;
}

public void setCarbookid(){
    this.carbookId = carbookId;
}

public String getManufacturername(){
    return manufacturername;
}
public void setManufacturername(){
    this.manufacturername = manufacturername;
}

public String getModelname(){
    return modelname;
}

public void setModelname(){
    this.modelname = modelname;
}
public String getPriceday(){
    return price_day;
}
public void setPriceday(){
    this.price_day = price_day;
}
}

但由于某种原因，只显示一条记录，这是最后一条，它应该返回表格中的所有内容（据说）

enter image description here

所以我很感激，如果你们能帮助我，并指出我做错了什么，并帮助我获得表格中显示的所有记录，如此

enter image description here

再次感谢

更新

根据Shuddh的指示，我对代码进行了一些更改，但它仍然无法解决某些血腥的原因

public ArrayList displayCarList(){

 try {
  try {
      Class.forName("com.mysql.jdbc.Driver");
  } catch (ClassNotFoundException ex) {
      Logger.getLogger(displayCarList.class.getName()).log(Level.SEVERE, null, ex);
  }
  con =DriverManager.getConnection ("jdbc:mysql://localhost:3306/rentalcar","root","");
  stmt = con.createStatement();
  rs = stmt.executeQuery("SELECT * FROM carlist");
  while(rs.next()){
     int i = 1;
     while(i <= 12){
         carlist.add(rs.getString(i++));
     }  
  }
  stmt.close();
  con.close();
  // displaying record
  } catch (SQLException e) {
       System.out.println("couldnotconnecYO");
  }
 return carlist;
        }

它现在在每个列中返回null

Answer 1

您获得最后一行的原因是因为您没有将其他行存储在任何位置。因此它会覆盖变量并捕获最后一行。将局部变量存储为列表，这样就可以了。

创建一个List并将每个结果集添加到

中

try {
  try {
      Class.forName("com.mysql.jdbc.Driver");
  } catch (ClassNotFoundException ex) {
      Logger.getLogger(displayCarList.class.getName()).log(Level.SEVERE, null, ex);
  }
  con =DriverManager.getConnection ("jdbc:mysql://localhost:3306/rentalcar","root","");
  stmt = con.createStatement();
  rs = stmt.executeQuery("SELECT * FROM carlist");
  while(rs.next()){
     carbookId = rs.getString(1);
     manufacturername= rs.getString(2);
     modelname = rs.getString(3);
     price_day = rs.getString(4);
     // add to list here.
  }
  stmt.close();
  con.close();
  // displaying record
  } catch (SQLException e) {
       System.out.println("couldnotconnecYO");
  }
return List. // If you have no idea about list in java google it and learn how to use it

将上述代码写在方法中而不是构造函数中。

在jsp中显示mysql表

1 个答案: