I have exactly same function in both Main method and other method JDBC connection is working fine. If I call the other function it throws error java.sql.SQLException: No suitable driver found for jdbc:mysql://localhost:3306/wine:
I have included MySql Driver in library [Netbeans];
processRequest method:
protected void processRequest(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html;charset=UTF-8");
String process = (String) request.getParameter("process");
String name = (String) request.getParameter("process");
String phone=(String) request.getParameter("phone");
String email = (String) request.getParameter("email");
String pwd = (String) request.getParameter("pwd");
PrintWriter out = response.getWriter();
out.println("Hello");
signup(out,process,name,email,phone,pwd);
}
signup method:
private static int signup(PrintWriter out,String process,String name,String email,String phone,String pwd){
Connection con = null;
PreparedStatement stmt = null;
ResultSet rs = null;
try {
con = DriverManager.getConnection("jdbc:mysql://localhost:3306/wine", "root", "");
out.println("Process Not Found");
if (process == "signup") {
String query = "INSERT INTO user(name,phone,email,password,role) VALUES(?,?,?,?,1)";
stmt = con.prepareStatement(query);
stmt.setString(1, name);
stmt.setString(2, phone);
stmt.setString(3, email);
stmt.setString(4, pwd);
stmt.execute();
} else {
out.println("Process Not Found");
}
} catch (SQLException e) {
// do something appropriate with the exception, *at least*:
out.println(e);
e.printStackTrace();
return 0;
}
return 1;
}
Main Method :
public static void main(String[] args) {
Connection con = null;
PreparedStatement stmt = null;
ResultSet rs = null;
String process = "signup";
String name = "Test";
String phone="45885";
String email = "Test#gmail.com";
String pwd = "dkjsdh";
try {
con = DriverManager.getConnection("jdbc:mysql://localhost:3306/wine", "root", "");
if (process == "signup") {
String query = "INSERT INTO user(name,phone,email,password,role,status) VALUES(?,?,?,?,1,1)";
stmt = con.prepareStatement(query);
stmt.setString(1, name);
stmt.setString(2, phone);
stmt.setString(3, email);
stmt.setString(4, pwd);
stmt.execute();
} else {
System.out.println("Process Not Found");
}
} catch (SQLException e) {
// do something appropriate with the exception, *at least*:
System.out.println(e);
e.printStackTrace();
}
}
There are two options that can be tried:
Class.forName("com.mysql.jdbc.Driver").newInstance() //older bug
and
Class.forName("com.mysql.jdbc.Driver");
In the comment I pasted the older bug solution when I meant to paste the second one.
Either way I am glad that it worked out for you
Related
I'm trying to set up JDBC but I'm getting this error.
I tried adding the dependency in pom.xml and even jar file nothing works. I tried the methods mentioned in previous questions, nothing works.
public class FilmLength {
public static void main(String[] args) throws SQLException {
Connection dbCon = null;
PreparedStatement st = null;
ResultSet rs = null;
String url = "jdbc:mysql//localhost:3306/sakila";
String username = "devuser";
String password = "Demo#123";
String query = "select * from film ";
try {
Class.forName("com.mysql.jdbc.Driver");
dbCon = DriverManager.getConnection(url,username,password);
st = dbCon.prepareStatement(query);
rs = st.executeQuery();
while(rs.next()) {
String title = rs.getString(1);
System.out.println(title);
}
} catch (Exception e) {
e.printStackTrace();
}
finally {
dbCon.close();
st.close();
rs.close();
}
}
}
Instead of
String url = "jdbc:mysql//localhost:3306/sakila";
it should be
String url = "jdbc:mysql://localhost:3306/sakila";
I tried to select some data from a MYSQL database tab and insert them into another MYSQL database table.
This is my servlet code
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
processRequest(request, response);
PrintWriter out = response.getWriter();
String name = request.getParameter("name");
ArrayList al = null;
int size = 0;
size = AcceptDao.getData(name);
if (size>0) {
out.println("<script type=\"text/javascript\">");
out.println("alert('Successfully Employee Added');");
out.println("</script>");
} else {
out.println("<script type=\"text/javascript\">");
out.println("alert('Try Again');");
out.println("</script>");
}
}
and here is my java code to do select and insert data.
public static int getData(String Uname) {
ArrayList al = null;
int status = 0;
String name = null;
String role = null;
String pass = null;
try {
Connection con = ConnectionProvider.getCon();
String query = "SELECT noty_name,noty_user_role,noty_pass FROM notification WHERE noty_name='" + Uname + "'";
Statement st = con.createStatement();
ResultSet rs = st.executeQuery(query);
al = new ArrayList();
while (rs.next()) {
name = rs.getString("noty_name");
role = rs.getString("noty_user_role");
pass = rs.getString("noty_pass");
}
PreparedStatement ps = con.prepareStatement("INSERT INTO employee (name,user_role,pass) values(?,?,?)");
ps.setString(1, name);
ps.setString(2, role);
ps.setString(3, pass);
status = ps.executeUpdate();
} catch (Exception e) {
}
return status;
}
this isn't work properly. this code doesn't do select and insert. What is the wrong with this code.
Please note that the code part for "insert" is outside the loop. So only the last data in the loop will be inserted, if available.
Moreover there is no need of while(rs.next) loop. you can use if(rs.next) condition if you are sure that you be passing a unique name in the request.
while (rs.next()) {
name = rs.getString("noty_name");
role = rs.getString("noty_user_role");
pass = rs.getString("noty_pass");
}
/* The Below part is wrong */
PreparedStatement ps = con.prepareStatement("INSERT INTO employee (name,user_role,pass) values(?,?,?)");
ps.setString(1, name);
ps.setString(2, role);
ps.setString(3, pass);
status = ps.executeUpdate();
Instead use this below code
public static int getData(String Uname) {
ArrayList al = null;
int status = 0;
String name = null;
String role = null;
String pass = null;
try {
Connection con = ConnectionProvider.getCon();
String query = "SELECT noty_name,noty_user_role,noty_pass FROM notification WHERE name='" + Uname + "'";
Statement st = con.createStatement();
ResultSet rs = st.executeQuery(query);
al = new ArrayList();
PreparedStatement ps = con.prepareStatement("INSERT INTO employee (name,user_role,pass) values(?,?,?)");
while (rs.next()) {
name = rs.getString("noty_name");
role = rs.getString("noty_user_role");
pass = rs.getString("noty_pass");
ps.setString(1, name);
ps.setString(2, role);
ps.setString(3, pass);
status = ps.executeUpdate();
}
} catch (Exception e) {
}
return status;
}
Please help me fix the error in this program. The problem is, even if I use the correct username and password, I can't create a verified login.
public class LoginDao {
public static boolean CheckUser(String Username,String Password)
{
boolean st =false;
String dbUsername, dbPassword;
try{
Class.forName("com.mysql.jdbc.Driver");
Connection con=DBConnection.getConnection();
String qry ="select *user where Username=? and Password=?";
PreparedStatement pst = con.prepareStatement(qry);
//pst.setString(1, Username);
//pst.setString(2, Password);
pst.executeQuery(qry);
ResultSet rs = pst.getResultSet();
while(rs.next()){
dbUsername = rs.getString("Username");
dbPassword = rs.getString("Password");
if(dbUsername.equals(Username) && dbPassword.equals(Password)){
System.out.println("Welcome");
st = true;
}
}
}
catch(Exception e)
{
e.printStackTrace();
}
return st;
}
}
Check your SQL query? You are missing a FROM before * and user. Also you need to set the parameters when using a PreparedStatement, you have them commented out.
UPDATE
Try this:
public class LoginDao {
public static boolean CheckUser(final String username, final String password) {
final String qry ="SELECT * FROM user WHERE Username=? AND Password=?";
Connection con = null;
PreparedStatement pst;
ResultSet rs = null;
try {
Class.forName("com.mysql.jdbc.Driver");
con = DBConnection.getConnection();
pst = con.prepareStatement(qry);
pst.setString(1, username);
pst.setString(2, password);
pst.executeQuery(qry);
rs = pst.getResultSet();
// Notice I changed the 'while' by 'if'
if (rs.next()) {
return (username.equals(rs.getString("Username")) && password.equals(rs.getString("Password")));
}
} catch (final Exception e) {
e.printStackTrace();
} finally {
// close/release (database resources) 'con', 'pst', 'rs' here
}
return false;
}
}
I am trying to make a simple login form. Every thing is working fine, connection is established, query is executed but ResultSet is still empty so always getting redirected to fail.jsp. No error no warning at all.
Servlet code:
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String name = request.getParameter("name");
String password = request.getParameter("password");
modelclass md = new modelclass();
daoclass dao = new daoclass();
md.setName(name);
md.setPassword(password);
System.out.println("this just before the sql query on the main servlet page");
String sql = "Select * from USERADD where name = ? and password= ?";
String result = dao.guser(md, sql);
if (result.equals("success")) {
response.sendRedirect("welcome.jsp");
} else {
response.sendRedirect("fail.jsp");
}
}
This is the DAO class which makes connection.
Data Access code(dao.java):
public class daoclass {
public static String username = "NickNeo";
public static String password = "123123";
public static String driver = "com.ibm.db2.jcc.DB2Driver";
public static String url = "jdbc:db2://localhost:50000/CITYLIFE";
public static Connection con = null;
public static PreparedStatement ps = null;
static {
try {
Class.forName(driver);
System.out.println("before connection");
con = DriverManager.getConnection(url, username, password);
System.out.println("Connection Successfullll......!!!!!!");
} catch(Exception e) {
e.printStackTrace();
}
}
public String guser(modelclass obj, String sql) {
try {
System.out.println("entry into try block");
ps=con.prepareStatement(sql);
ps.setString(1, obj.getName());
ps.setString(2, obj.getPassword());
System.out.println("before query");
ResultSet rs = ps.executeQuery();
System.out.println("query executed");
int i = 0;
while(rs.next()) {
System.out.println("entered into while loop");
++i;
}
if (i >= 1) {
return "success";
} else {
System.out.println("this is inside else of while block");
return "fail";
}
} catch(Exception e) {
e.printStackTrace();
}
System.out.println("this is the most outer fail statement");
return "fail";
}
}
the rs is always empty. tried many things but still getting rs as empty. please help
I'm currently being thrown into the depths by my school and they are expecting me to program a simple login form using sql. They have given us brief examples on how they use JDBC and what it all is, but haven't really explained step by step how to use it on our own. Therefore i have snatched a bit of code from an example but i'm unable to get it working. I keep receiving an nullpointerexception and i can't figure out why :(
Here's the connection class:
package Database;
import java.sql.*;
public class MySQLConnection {
public static final String DRIVER = "com.mysql.jdbc.Driver";
public static final String DBURL = "jdbc:mysql://localhost/corendon";
public static final String DBUSER = "root";
public static final String DBPASS = "simplepass";
private ResultSet result = null;
private int affectedRows = -1;
Connection conn = null;
public void startConnection() {
try {
Class.forName(DRIVER);
DriverManager.setLoginTimeout(5);
conn = DriverManager.getConnection(DBURL, DBUSER, DBPASS);
} catch (Exception e) {
}
}
public void closeConnection() {
try {
if (conn != null && !conn.isClosed()) {
conn.close();
}
} catch (Exception e) {
}
conn = null;
}
public ResultSet performSelect(PreparedStatement prdstmt) throws SQLException {
result = prdstmt.executeQuery();
return result;
}
public int performUpdate(PreparedStatement prdstmt) throws SQLException {
affectedRows = prdstmt.executeUpdate();
return affectedRows;
}
public Connection getConnection() {
return conn;
}
}
And here is the method i'm getting the exception in (in a different class):
MySQLConnection conn = new MySQLConnection();
public void compareData(int id, String pass) throws SQLException{
ResultSet rs = null;
PreparedStatement prdstmt = null;
String query = "SELECT id, password FROM users WHERE id=?, password=?";
conn.startConnection();
prdstmt = conn.getConnection().prepareStatement(query);
prdstmt.setInt(1, id);
prdstmt.setString(2, pass);
rs = conn.performSelect(prdstmt);
while (rs.next()){
String tempPass = rs.getString("password");
int tempId = rs.getInt("id");
}
if(conn != null){
conn.closeConnection();
}
}
I'm getting the nullpointerexception on line:
prdstmt = conn.getConnection().prepareStatement(query);
Why does it throw an exception there, but not when i start the connection and also how do i solve this? Thanks in advance.
When you call startConnection(), you are throwing an Exception
public void startConnection() {
try {
Class.forName(DRIVER);
DriverManager.setLoginTimeout(5);
conn = DriverManager.getConnection(DBURL, DBUSER, DBPASS);
} catch (Exception e) {
//An exception occurs here, but you don't do anything about it
}
}
Therefore, when you call getConnection(), the conn variable is still null, which is throwing the NullPointerException.
Either make startConnection() throw an exception so that you're forced to deal with it (this is usually how most JDBC drivers work anyway), or check to see if the conn variable is null before you start using it.
public void compareData(int id, String pass) throws SQLException{
ResultSet rs = null;
PreparedStatement prdstmt = null;
String query = "SELECT id, password FROM users WHERE id=?, password=?";
conn.startConnection();
if (conn.getConnection() == null) {
throw new SQLException("Connection is null!");
}
Or (what I think would personally be better)
public void startConnection() throws Exception {
Class.forName(DRIVER);
DriverManager.setLoginTimeout(5);
conn = DriverManager.getConnection(DBURL, DBUSER, DBPASS);
}
public void compareData(int id, String pass) throws SQLException{
ResultSet rs = null;
PreparedStatement prdstmt = null;
String query = "SELECT id, password FROM users WHERE id=?, password=?";
try {
conn.startConnection();
} catch (Exception e) {
throw new SQLException(e);
}
Also as a tip, you should probably avoid declaring your classes as the same name of other classes you are using. This is all happening in your own MySQLConnection class, but that could be confusing with the actual com.mysql.jdbc.MySQLConnection class.