JavaBean连接mysql总是出HTTP-500错误
各位帮忙看看啊,我有几个这种程序都是这一种错误,郁闷几天啦!!!
jsp程序如下:
<%@ page contentType= "text/html; charset=gb2312 " language= "java " import= "java.sql.* " errorPage= " " %>
<jsp:useBean id= "DBconn1 " scope= "page " class= "NewsVersion.MySQLconn "/>
<html>
<head>
<meta http-equiv= "Content-Type " content= "text/html; charset=gb2312 ">
<title> 无标题文档 </title>
</head>
<body>
<%
String String_SQL= "select * from book ";
ResultSet rs=DBconn1.executeQuery(String_SQL);
String usercontent;
if(rs.next())
{
usercontent=rs.getString( "about ");
}
out.print(usercontent);
%>
</body>
</html>
Bean程序如下:
package NewsVersion;
import java.sql.*;
public class MySQLconn {
String DBDriver = "org.gjt.mm.mysql.Driver ";
String ConnStr = "jdbc:mysql://localhost:3306/bookstore?user=root&password=200000&useUnicode=true&characterEncoding=8859_1 ";
Connection conn = null;
ResultSet rs = null;
public MySQLconn(){
try{
Class.forName(DBDriver);
//加载数据库驱动程序
}
catch(java.lang.ClassNotFoundException e) {
System.err.println( "MySQLconn(): "+e.getMessage());
}
}
public ResultSet executeQuery(String sql){
//以记录集为返回值的函数
rs = null;
try {
conn = DriverManager.getConnection(ConnStr);
//与DBMS建立链接
Statement stmt = conn.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_READ_ONLY);
rs = stmt.executeQuery(sql);
}
catch(SQLException ex) {
System.err.println( "aq.executeQuery: "+ex.getMessage());
}
return rs;
}
}
错误提示:
HTTP Status 500 -
--------------------------------------------
type Exception report
message
description The server encountered an internal error () that prevented it from fulfilling this request.
exception
org.apache.jasper.JasperException: /dbBean4/1.jsp(3,0) The value for the useBean class attribute NewsVersion.MySQLconn is invalid. org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:512) org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:377) org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:314) org.apache.jasper.servlet.JspServlet.service(JspServlet.java:264) javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
root cause
org.apache.jasper.JasperException: /dbBean4/1.jsp(3,0) The value for the useBean class attribute NewsVersion.MySQLconn is invalid. org.apache.jasper.compiler.DefaultErrorHandler.jspError(DefaultErrorHandler.java:39) org.apache.jasper.compiler.ErrorDispatcher.dispatch(ErrorDispatcher.java:405) org.apache.jasper.compiler.ErrorDispatcher.jspError(ErrorDispatcher.java……
这只是一个代表，每一个Bean调mysql的程序都这样，网上拷的也是如此，高手指点下吧
[解决办法]
The value for the useBean class attribute NewsVersion.MySQLconn is invalid. 报错是你BEAN CLASS无效呀
[解决办法]
在你的Bean程序里写一个main()方法，看能不能打出rs的值确定是不是Bean的问题或mysql问题。。
我的异常网推荐解决方案：The server encountered an internal error () that prevented it from fulfilling this request.,http://www.myexception.cn/java-web/317.html
