Java EE database connection using "rs" is null, please?-CodePudding

Java. Lang. NullPointerException: always invoke a "Java. SQL. The ResultSet. Next ()" because "rs" is null

 & lt; % @ page language="Java" contentType="text/HTML. Charset=ISO - 8859-1 "
PageEncoding="ISO - 8859-1" % & gt; 
<% @ page import="Java. SQL. *" % & gt; 
<% @ page import="qwer. DbBean" % & gt; 
 
 
 
 Verify the page & lt;/title> <br/><meta HTTP - equiv="content-type" Content="text/HTML. Charset=utf-8 "& gt; <br/><meta charset="ISO - 8859-1" & gt; <br/><title> Insert the title here 
 
<body> 
<% 
The String with username1 is=request. The getParameter (" username "); 
String password1=request. The getParameter (" password "); 
Boolean validated=false; 
Boolean validated1=false; 
The Connection conn=null; 
The Statement Statement=null; 
The ResultSet rs=null; 

Try {
DbBean myDbBean=new DbBean (); 
MyDbBean. OpenConnection (); 
String SQL="select * from excel"; 
//if (myDbBean. Conn==null) out. Print (" no!" ); 
Rs=myDbBean. ExecuteQuery (SQL); 
} the catch (Exception e) {
e.printStackTrace(); 
} 
While (rs), next ()) {
Out. Print (rs. Get string (" id ") + "- & gt;" ); 
Out. Print (rs. Get string (" username ") + "- & gt;" ); 
Out. Print (rs. Get string (" password ")); 

} 
/* the try {

Class.forName("com.mysql.jdbc.Driver"); 
The String url="JDBC: mysql://127.0.0.1:3306/wwy? ServerTimezone=UTC "; 
String user="root"; 
String password="wwy112358"; 

Conn=DriverManager. GetConnection (url, user, password); 
The statement=conn. CreateStatement (); 
If (conn==null) out. Println (" NO connect! 
" ); 

String SQL="select * from excel"; 
Rs=statement. ExecuteQuery (SQL); 
While (rs), next ()) {
Out.println (rs. Get string (" id ") + "- & gt;" ); 
Out.println (rs. Get string (" username ") + "- & gt;" ); 
Out.println (rs. Get string (" password ")); 
} 

Out.println (" success! 
" ); 
} the catch (Exception e) {
//TODO Auto - generated the catch block, 
e.printStackTrace(); 
} the finally {
Try {
If (rs!=null) rs. The close (); 
} the catch (SQLException e) {
e.printStackTrace(); 
} the finally {
Try {
If (the statement!=null) statement. The close (); 
} the catch (SQLException e) {
e.printStackTrace(); 
} the finally {
Try {
If (conn!=null) conn. Close (); 
} the catch (SQLException e) {
e.printStackTrace(); 
} 
} 
} 
} 
*/
%>

This is a JSP file

 package qwer; 
Import the Java. SQL. *; 
Public class DbBean {

Public Statement STMT=null; 
Public Connection conn=null; 
Public ResultSet rs=null; 
Public DbBean () {} 

Public void openConnection () {
Try {
Class.forname (". Com. Mysql. JDBC Driver "); 
The String url="JDBC: mysql://127.0.0.1:3306/wwy? ServerTimezone=UTC& UseSSL=false "; 
Conn=DriverManager. GetConnection (url, "root", "wwy112358"); 
//STMT=conn. CreateStatement (); 
//return conn. 
} 
The catch (a ClassNotFoundException e) {
System. Err. Println (" openConn: "+ um participant etMessage ()); 
} 
The catch (SQLException e) {
System. Err. Println (" openConn: "+ um participant etMessage ()); 
} 
The catch (Exception e) {
System. Err. Println (" openConn: "+ um participant etMessage ()); 
} 
//return conn. 

} 

Public ResultSet executeQuery (String SQL) {
Try {
STMT=conn. CreateStatement (); 
Rs=STMT. ExecuteQuery (SQL); 
} 
The catch (SQLException e) {
System. Err. Println (" executeQuery: "+ um participant etMessage ()); 
} 
return rs; 
} 

Public int executeUpdate (String SQL) {
Int n=0; 
Try {
STMT=conn. CreateStatement (); 
N=STMT. ExecuteUpdate (SQL); 
} 
The catch (Exception e) {
System. The out. Print (e. oString ()); 
} 
Return n. 
} 
Public void closeConnection () {
Try {
If (rs!=null) 
rs.close(); 
} 
The catch (SQLException e) {
System. Err. Println (" closeRs: "+ um participant etMessage ()); 
} 
Try {
If (STMT!=null) 
STMT. Close (); 
} 
The catch (SQLException e) {
System. Err. Println (" closeStmt: "+ um participant etMessage ()); 
} 
Try {
If (conn!=null) 
Conn. Close (); 
} 
The catch (SQLException e) {
System. Err. Println (" closeConn: "+ um participant etMessage ()); 
} 
} 
/* public static void main (String [] args) {
Boolean validated=false; 
Boolean validated1=false; 
The Connection conn=null; 
The Statement Statement=null; 
The ResultSet rs=null; 
Try {
DbBean myDbBean=new DbBean (); 
//conn=myDbBean openConnection (); 
String SQL="select * from excel"; 
Rs=myDbBean. ExecuteQuery (SQL); 
} the catch (Exception e) {
e.printStackTrace(); 
} 

Try {
While (rs), next ()) {
System. The out. Print (rs. Get string (" id ") + "- & gt;" ); 
System. The out. Print (rs. Get string (" username ") + "- & gt;" ); 
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