PreparedStation不使用Java类的方法参数从MySql获取数据
我试图从jsp页面传递用户名和密码，以验证Java类LogMeIn.Java中的方法，但结果是“false”。然而，当我硬编码值abc/abc时，我确实得到了“通过”的结果。这是成功的 请告诉我为什么它不接受通过jsp传递的参数 -LogMeIn.java-PreparedStation不使用Java类的方法参数从MySql获取数据,java,jsp,jdbc,Java,Jsp,Jdbc,我试图从jsp页面传递用户名和密码，以验证Java类LogMeIn.Java中的方法，但结果是“false”。然而，当我硬编码值abc/abc时，我确实得到了“通过”的结果。这是成功的 请告诉我为什么它不接受通过jsp传递的参数 -LogMeIn.java- package org.cms.model; import java.sql.Connection; import java.sql.ResultSet; import java.sql.SQLExce
package org.cms.model;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.sql.PreparedStatement;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.sql.DataSource;
public class LogMeIn {
public boolean Authenticate( String username, String password ) {
Connection connection = null;
// Statement statement = null;
ResultSet resultSet = null;
PreparedStatement pst = null;
String query;
boolean result = false;
try {
Context initCtx = new InitialContext();
Context envCtx = (Context) initCtx.lookup("java:comp/env");
DataSource ds = (DataSource) envCtx.lookup("jdbc/TestDB");
connection = ds.getConnection();
//statement = connection.createStatement();
query = "select name from account where name= ? and password = ?";
pst = connection.prepareStatement(query);
pst.setString(1, username);
pst.setString(2, password);
resultSet = pst.executeQuery();
int count=0;
if(resultSet.next())
{
count++;
}
if(count>0)
{
result = true;
}
else
{
result = false;
}
}
catch (SQLException e){
e.printStackTrace();
}
catch (Exception e){
e.printStackTrace();
}
finally {
if (resultSet != null) try { resultSet.close(); } catch (SQLException logOrIgnore) {}
if (connection != null) try { connection.close(); } catch (SQLException logOrIgnore) {}
}
return result;
}
}
package org.cms.controller;
import java.io.IOException;
import javax.servlet.RequestDispatcher;
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 org.cms.model.LogMeIn;
/**
* Servlet implementation class LoginServlet
*/
@WebServlet("/LoginServlet")
public class LoginServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String username;
String password;
username = request.getParameter("user");
password = request.getParameter("pass");
LogMeIn a = new LogMeIn();
boolean result = a.Authenticate(username, password);
System.out.println(result);
if (result) {
request.setAttribute("loginresult","Pass");
RequestDispatcher dispatcher = request.getRequestDispatcher("Login.jsp");
dispatcher.forward(request, response);
}
else {
request.setAttribute("loginresult","Failed");
RequestDispatcher dispatcher = request.getRequestDispatcher("Login.jsp");
dispatcher.forward(request, response);
}
}
}
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%@ taglib uri="http://java.sun.com/jsp/jstl/functions" prefix="fn" %>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<title>Login</title>
<link rel="stylesheet" href="css/style.css" type="text/css"></link>
<script language="JavaScript" type="text/JavaScript" src="validate.js"> </script>
</head>
<body>
<form enctype="multipart/form-data" onSubmit="return validate(this)" method="post" action="LoginServlet" class="form">
<table border = "0">
<tr align="left" valign="top">
<td>User Name:</td>
<td><input type="text" name ="user" class="inputbox"/></td>
</tr>
<tr align="left" valign="top">
<td>Password:</td>
<td><input type="password" name ="pass" class="inputbox" /></td>
</tr>
<tr align="left" valign="top">
<td></td>
<td><input type="submit" name="submit"
value="submit" class="fb8"/></td>
</tr>
</table>
<c:out value="${loginresult}" > </c:out>
</form>
</body>
</html>
非常感谢使用setAttribute方法。此方法设置请求的属性值，稍后在servlet中通过dispatcher方法传递请求对象来检索该属性。属性的设置值由请求对象的getAttribute方法检索
http://www.roseindia.net/servlets/request-parameter.shtml
http://www.roseindia.net/tutorial/servlet/passParameters.html
JSP传递给LogMeIn的参数是什么？您已经将它们打印到控制台了吗？validate做什么？旁注：LogMeIn中catch块之前的最后12行可以减少为result=resultSet.next；很可能你们需要用引号或者类似的东西来包装它们。谢谢你们！Validate正在查看一个不存在的javascript文件。问题是由于Validate方法的原因，将null参数传递给servlet。谢谢你的建议，我已经在我的代码中做了更改。你能回答这个问题吗？