sql语法错误(使用jstl标记)
sql语法错误(使用jstl标记)
提问于 2016-07-05 14:13:09
我把username，column name和new entry从一个jsp中的用户更新。我正在尝试使用jstl标记更新我的SQL数据库表，并显示更新后的表。jsp页面没有打开，它在我的update sql查询中给出一条语法错误的消息。
我的jsp页面：
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<%@ page import="java.io.*,java.util.*,java.sql.*"%>
<%@ page import="javax.servlet.http.*,javax.servlet.*" %>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/sql" prefix="sql"%>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Found page</title>
<style>
a:link, a:visited {
background-color:darkolivegreen;
color: white;
padding: 10px 25px;
text-align: center;
width:100px;
text-decoration: none;
display: inline-block;
border-radius:20px;
}
a:hover, a:active {
background-color: lightgreen;
}
header {
background-color:teal;
color:white;
text-align:center;
padding:5px;
}
#file {
font-family: "Trebuchet MS", Arial, Helvetica, sans-serif;
border-collapse: collapse;
width: 100%;
}
#file td, #file th {
border: 2px solid black;
text-align: left;
padding: 8px;
}
#file tr:hover {background-color: #ddd;}
#file th {
padding-top: 12px;
padding-bottom: 12px;
background-color: lightslategray;
color: white;
}
section {
height:270px;
width:1050px;
float:right;
padding:87px;
}
footer {
background-color:black;
float:bottom;
color:white;
clear:both;
text-align:center;
padding:5px;
}
</style>
</head>
<body style="background-color:lightsteelblue;">
<%
String userName = null;
String sessionID = null;
Cookie[] cookies = request.getCookies();
if (cookies != null) {
for (Cookie cookie : cookies) {
if (cookie.getName().equals("user")) {
userName = cookie.getValue();
}
}
}
%>
<header>
<h1>File Tracking System</h1>
<div><span style="float:right">Hi <%=userName%></span></div>
<br>
<form style="float:right" action=" LogoutServlet" method="post">
<input type="submit" value="Logout" >
</form>
<br>
</header>
<br>
<a href="file.jsp">1.Insert New File</a>
<a href="fileStatus.jsp">2.Change File Status</a>
<a href="found.jsp">3.Search your File</a>
<a href="checkstatus.jsp">4.Check File Status</a>
<br>
<br>
<form method="POST">
User ID:<br><input type="text" name="user" value="" size="20" />下拉列表中的这些选项拼写与userdetails表中我的列名相同
Alter:<br><select name="use">
<option>userName</option>
<option>password</option>
<option>role</option>
<option>firstname</option>
<option>lastname</option>
<option>departmentname</option>
<option>email</option>
<option>mobile</option>
</select>
New Entry:<br><input type="text" name="enter" value="" size="20" />
<input type="submit" value="submit" name="submit" />
</form>
<br>
<section>
<sql:setDataSource var="snapshot" driver="com.mysql.jdbc.Driver"
url="jdbc:mysql://localhost/login"
user="root" password="root"/>udate sql查询-
其形式为( update table_name set table_column="xyz“where column_name= "abc"；)
<sql:update dataSource="${snapshot}" var="result">
update usertable set "${param.use}"="${param.enter}" where username="${param.user}";
</sql:update>
<sql:query dataSource="${snapshot}" var="result">
select * from usertable where username="${param.user}";
</sql:query>
<table id="file">
<tr>
<th>UserName</th>
<th>Password</th>
<th>Role</th>
<th>First Name</th>
<th>Last Name</th>
<th>Department Name</th>
<th>Email</th>
<th>Mobile Number</th>
</tr>
<c:forEach var="row" items="${result.rows}">
<tr>
<td><c:out value="${row.username}"/></td>
<td><c:out value="${row.password}"/></td>
<td><c:out value="${row.role}"/></td>
<td><c:out value="${row.firstname}"/></td>
<td><c:out value="${row.lasttname}"/></td>
<td><c:out value="${row.departmentname}"/></td>
<td><c:out value="${row.email}"/></td>
<td><c:out value="${row.mobile}"/></td>
</tr>
</c:forEach>
</table>
</section>
<footer>
Copyright 2016 NSIC. All right reserved.
</footer>
</body>
</html>sql的正确语法应该是什么？有没有其他方法可以让我这样做呢？我使用了另一种方法，在alter.jsp中提交值并在servlet changeServlet.java中获取它们，但它没有显示任何错误，也没有被重定向到任何地方，它只是打开http://localhost:8080/test9/changeServlet，并停留在这里显示一个白色空白页面。
package bean;
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
public class changeServlet extends HttpServlet {
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
//request.getRequestDispatcher("link.html").include(request, response);
Cookie[] cookies = request.getCookies();
if(cookies != null){
for(Cookie cookie : cookies){
if(cookie.getName().equals("JSESSIONID")){
System.out.println("JSESSIONID="+cookie.getValue());
break;
}
}
}
HttpSession session = request.getSession(false);
System.out.println("admin="+session.getAttribute("admin"));
if(session!=null && session.getAttribute("admin") != null){
String admin=(String)session.getAttribute("admin");
boolean status=false;
try{
String user=request.getParameter("user");
String column=request.getParameter("column");
String data=request.getParameter("data");
boolean checkc=checkchar.value(column);
boolean checkp=checkchar.value(data);if语句检查任何错误的条目或空值，当提交错误的条目时，它将重定向到entry.jsp。这意味着它在这里之前是工作的，但在这个之后就不工作了。
if(checkc==true&&checkp==true) {
Connection con=ConnectionProvider.getCon();
String sql="update usertable set '"+column+"'='"+data+"' where username='"+user+"'";
PreparedStatement pstmt =con.prepareStatement(sql);
int rs=pstmt.executeUpdate();
if(rs>0){status=true;}
if(status){
PrintWriter out= response.getWriter();
out.print("data updated,"+admin);
response.sendRedirect("updated.jsp");
}
else
{
PrintWriter out= response.getWriter();
out.print("failed to update");
response.sendRedirect("notinsert.jsp");
}
}
else{response.sendRedirect("entry.jsp");}
}catch(SQLException e){}
}else{
RequestDispatcher rd = getServletContext().getRequestDispatcher("/index.html");
PrintWriter out= response.getWriter();
out.println("<font color=red>Either user name or password is wrong.</font>");
rd.include(request, response);
}
}
}页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/38196336
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