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我正在采取username，column name和new entry从用户在jsp更新。 我想用jstl标签更新我的SQL数据库表，并且还显示更新后的表。 jsp页面未打开，它在我的更新sql查询中给出语法错误消息。sql语法错误（使用jstl标签）
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" />
在下拉列表中选择这些选项的拼写是相同的UserDetails表我的列名
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公司的SQL查询 -
它是形式（更新TABLE_NAME组table_column = “XYZ”，其中列名= “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>
应该是什么SQL的语法是否正确？有没有其他方法可以做到这一点？ 我使用了另一种方式，我在alter.jsp中提交值，并将它们置于servlet changeServlet.java中，但它不显示任何错误，并且在任何地方只是打开http://localhost:8080/test9/changeServlet并且卡在这里显示白色空白页面时不会显示任何错误。
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);
的if语句检查任何错误的项目或空值时提交错误输入重定向到entry.jsp。这意味着它在这里工作，但在此之后不起作用。
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);
}
}
}
添加单引号arround char值 – Jens
你的意思是这样的------更新usertable设置'$ {param.use}'='{param.enter}'其中username ='$ {参数。用户}'; –
它不工作 –