连接数据库的BEAN!!
帮我看看这个连接数据库的BEAN有什么错误?为什么在服务器上总出现空指针错误
空指针问题在executeQuery()方法那里
package ****;
import java.sql.*;
import java.lang.*;
public class conn{
Connection conn=null;
Statement stmt=null;
ResultSet rs=null;
String sDBDriver="org.gjt.mm.mysql.Driver";
String sConnStr="jdbc:mysql://localhost/ebaroom_cxc_cc?user=******&password=*****useUnicode=true&characterEncoding=ISO-8859-1";
public conn(){
try{
Class.forName(sDBDriver);
conn=DriverManager.getConnection(sConnStr);
}catch(SQLException e){
System.err.println("错误11:"+e.getMessage());
}catch(java.lang.ClassNotFoundException e){
System.err.println("错误22:"+e.getMessage());
}
}
public ResultSet executeQuery(String sql) {
try {
stmt=conn.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_READ_ONLY);
rs=stmt.executeQuery(sql);
}
catch(SQLException ex) {
System.err.println("错误33" + ex.getMessage());
System.err.println("错误44 " + sql);
}
return rs;
}
public boolean executeUpdate(String sql) {
try {
stmt=conn.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_READ_ONLY);
stmt.executeUpdate(sql);
return true;
}
catch(SQLException ex) {
System.err.println("aq.executeUpdate: " + ex.getMessage());
System.err.println("aq.executeUpadatestrSQL: " + sql);
}
return false;
}
public void close(){
try{
if(rs!=null){
rs.close();
rs=null;
}
if(stmt!=null){
stmt.close();
stmt=null;
}
if(conn!=null){
conn.close();
conn=null;
}
}catch(Exception e){
System.err.println("错误3:"+e.getMessage());
}
}
}