jsp页面中的sql异常 [英] sql exception in jsp page
本文介绍了jsp页面中的sql异常的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我认为JSP代码为：
<％@ 页面 import = org.apache.tomcat.util.net.SSLUtil ％>
<！DOCTYPE HTML PUBLIC - // W3C // DTD HTML 4.01 Transitional // EN
http://www.w3.org/TR/html4/loose.dtd >
<％@ page import = java.sql。* ％>
<％@ page import = java.io。* ％>
< html >
< head >
< title > 与mysql数据库的连接< /标题 >
< / head >
< ; 正文 >
< h1 > 连接状态< ; / h1 >
<％
尝试 {
字符串 connectionURL = < span class =code-string> jdbc：mysql：//dbno2.cfghe6zvdgnoq7r.ap-southeast-2.rds.amazonaws.com:3306 / mydb？用户= aghil&安培;密码=密码1\" ;
连接连接= null ;
语句stmt = null ;
Class.forName（ com.mysql.jdbc.Driver）。newInstance（） ;
connection = DriverManager.getConnection（connectionURL）;
if （！connection.isClosed（））{
stmt = connection.createStatement（）;
}
out .println（ 使用TCP / IP成功连接到MySQL服务器... \ n）;
字符串 QueryString = 从mydb中选择用户名.userdetails WHERE username ='anil'和password ='password';
ResultSet rs;
字符串 sre = null ;
try {
PreparedStatement statement = connection.prepareStatement（QueryString）;
rs = statement.executeQuery（）;
sre = rs.getString（ 1 ）;
out .println（ \ n + sre）;
} catch （例外e）{
out .println（ \ n + e.toString（））;
}
connection.close（）;
} catch （例外情况）{
out .println（ 无法连接到数据库。 + ex）;
}
％>
< / body >
< / html >
及其在浏览器中的输出如下：
< html>< head>
< title>与mysql数据库连接< / title>
< / head>
< body>
连接状态
使用TCP /
成功连接到MySQL服务器b $ b
java.sql.SQLException：在开始结果集之前>< / html>
为什么会这样？怎么办？
解决方案
PreparedStatement statement = connection.prepareStatement（QueryString）;
rs = statement.executeQuery（）;
if（rs.next（））
sre = rs.getString（1）;
out.println（\ n+ sre） ;
I hava Jsp code as:
<%@page import="org.apache.tomcat.util.net.SSLUtil"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<%@ page import="java.sql.*" %>
<%@ page import="java.io.*" %>
<html>
<head>
<title>Connection with mysql database</title>
</head>
<body>
<h1>Connection status </h1>
<%
try {
String connectionURL = "jdbc:mysql://dbno2.cfghe6zvdgnoq7r.ap-southeast-2.rds.amazonaws.com:3306/mydb?user=aghil&password=password1";
Connection connection = null;
Statement stmt = null;
Class.forName("com.mysql.jdbc.Driver").newInstance();
connection = DriverManager.getConnection(connectionURL);
if (!connection.isClosed()) {
stmt = connection.createStatement();
}
out.println("Successfully connected to MySQL server using TCP/IP...\n");
String QueryString = "select username from mydb.userdetails WHERE username ='anil' and password='password'";
ResultSet rs;
String sre = null;
try {
PreparedStatement statement = connection.prepareStatement(QueryString);
rs = statement.executeQuery();
sre = rs.getString(1);
out.println("\n" + sre);
} catch (Exception e) {
out.println("\n" + e.toString());
}
connection.close();
} catch (Exception ex) {
out.println("Unable to connect to database." + ex);
}
%>
</body>
</html>
and its output in browser is as follows :
<html><head>
<title>Connection with mysql database</title>
</head>
<body>
Connection status
Successfully connected to MySQL server using TCP/
java.sql.SQLException: Before start of result set></html>
why this? what to do?
解决方案
PreparedStatement statement = connection.prepareStatement(QueryString);
rs = statement.executeQuery();
if(rs.next())
sre = rs.getString(1);
out.println("\n" + sre);
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