index.jsp内容:<html>
<head>
</head>
<body>
<%@ page language="java" import="java.sql.*"%>
<%@page contentType="text/html;charset=gb2312"%>
<jsp:useBean id="sqlBeans" class="sqlBeans.sql" scope="session"/>
<%! String sqlCommand,userName,password;%>
<%
sqlCommand = "select * from userme";
try
{
ResultSet rs = sqlBeans.executeQuery(sqlCommand);
if(rs == null)
{
out.println("1");
}
while(rs.next())
{
userName = rs.getString(1);
password = rs.getString(2);
}
out.print(userName);
out.print(password);
}
catch(Exception ex)
{
out.println(ex);
}
%>
</body>
</html>sql.java内容:package sqlBeans;
import java.sql.*;
public class sql
{
String sDBDriver = "oracle.jdbc.driver.OracleDriver";
String sConnStr = "jdbc:oracle:thin:@127.0.0.1:1521:icss";
String userName = "SOAR";
String password = "soar";
Connection conn = null;
ResultSet rs = null;
public sql()
{
try
{
Class.forName(sDBDriver);
}
catch(java.lang.ClassNotFoundException e)
{
System.err.println("sql_data(): " + e.getMessage());
}
} public ResultSet executeQuery(String sql)
{
rs = null;
try
{
conn = DriverManager.getConnection(sConnStr,userName,password);
Statement stmt = conn.createStatement();
rs = stmt.executeQuery(sql);
}
catch(SQLException e)
{
System.err.println("executeQuery: " + e.getMessage());
}
return rs;
}
public void executeUpdate(String sql)
{
try
{
conn = DriverManager.getConnection(sConnStr,userName,password);
Statement stmt = conn.createStatement();
stmt.executeUpdate(sql);
}
catch(SQLException e)
{
System.err.println("executeUpdate: " + e.getMessage());
}
}
}在TOMCAT下访问的时候会出现:“1 java.lang.NullPointerException ”
但是数据库部分没有问题,也就是说在从数据库中读取表的时候,返回结果是NULL,请问是在连接数据库的时候出现什么错误了吗?谢谢。
<head>
</head>
<body>
<%@ page language="java" import="java.sql.*"%>
<%@page contentType="text/html;charset=gb2312"%>
<jsp:useBean id="sqlBeans" class="sqlBeans.sql" scope="session"/>
<%! String sqlCommand,userName,password;%>
<%
sqlCommand = "select * from userme";
try
{
ResultSet rs = sqlBeans.executeQuery(sqlCommand);
if(rs == null)
{
out.println("1");
}
while(rs.next())
{
userName = rs.getString(1);
password = rs.getString(2);
}
out.print(userName);
out.print(password);
}
catch(Exception ex)
{
out.println(ex);
}
%>
</body>
</html>sql.java内容:package sqlBeans;
import java.sql.*;
public class sql
{
String sDBDriver = "oracle.jdbc.driver.OracleDriver";
String sConnStr = "jdbc:oracle:thin:@127.0.0.1:1521:icss";
String userName = "SOAR";
String password = "soar";
Connection conn = null;
ResultSet rs = null;
public sql()
{
try
{
Class.forName(sDBDriver);
}
catch(java.lang.ClassNotFoundException e)
{
System.err.println("sql_data(): " + e.getMessage());
}
} public ResultSet executeQuery(String sql)
{
rs = null;
try
{
conn = DriverManager.getConnection(sConnStr,userName,password);
Statement stmt = conn.createStatement();
rs = stmt.executeQuery(sql);
}
catch(SQLException e)
{
System.err.println("executeQuery: " + e.getMessage());
}
return rs;
}
public void executeUpdate(String sql)
{
try
{
conn = DriverManager.getConnection(sConnStr,userName,password);
Statement stmt = conn.createStatement();
stmt.executeUpdate(sql);
}
catch(SQLException e)
{
System.err.println("executeUpdate: " + e.getMessage());
}
}
}在TOMCAT下访问的时候会出现:“1 java.lang.NullPointerException ”
但是数据库部分没有问题,也就是说在从数据库中读取表的时候,返回结果是NULL,请问是在连接数据库的时候出现什么错误了吗?谢谢。
解决方案 »
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