MySQL User DAO

package com.evs.objava33.class19;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

public class MySqlUserDao extends Database implements UserDao {

public User validateUser(String name, String pass) {
Connection con = null;
PreparedStatement stmt = null;
ResultSet rs = null;
try {
con = getConnection();
stmt = con.prepareStatement(VALIDATE_USER);
stmt.setString(1, name);
stmt.setString(2, pass);
rs = stmt.executeQuery();
if (rs.next()) {
return new User(rs.getLong(1), rs.getString(2), rs.getString(3));
}
} catch (SQLException q) {
q.printStackTrace();
} finally {
returnResources(rs, stmt, con);
}
return null;
}

public User getUser(String userid) {
Connection con = null;
PreparedStatement stmt = null;
ResultSet rs = null;
try {
con = getConnection();
stmt = con.prepareStatement(ALL_USER + " WHERE userid=?");
stmt.setString(1, userid);
rs = stmt.executeQuery();
if (rs.next()) {
return new User(rs.getLong(1), rs.getString(2), rs.getString(3));
}
} catch (SQLException q) {
q.printStackTrace();
} finally {
returnResources(rs, stmt, con);
}
return null;
}

public List<User> allUsers() {
Connection con = null;
PreparedStatement stmt = null;
ResultSet rs = null;
List<User> list = null;
try {
con = getConnection();
stmt = con.prepareStatement(ALL_USER);
rs = stmt.executeQuery();
list = new ArrayList<User>();
while (rs.next()) {
list.add(new User(rs.getLong(1), rs.getString(2), rs
.getString(3)));
}
} catch (SQLException q) {
q.printStackTrace();
} finally {
returnResources(rs, stmt, con);
}
return list;
}

@Override
public boolean addUser(String username, String userpass) {
Connection con = null;
PreparedStatement stmt = null;
ResultSet rs = null;
try {
con = getConnection();
stmt = con.prepareStatement(ADD_USER);
stmt.setString(1, username);
stmt.setString(2, userpass);
int ret = stmt.executeUpdate();
return ret > 0;
} catch (SQLException q) {
q.printStackTrace();
} finally {
returnResources(rs, stmt, con);
}
return false;
}

/*
* (non-Javadoc)
*
* @see com.evs.objava33.class19.UserDao#deleteUser(java.lang.String)
*/
@Override
public void deleteUser(String userid) {
executeQuery("DELETE FROM user where userid=" + userid);
}

public boolean updateUser(String userid, String username, String userpass) {
return executeQuery("UPDATE user SET username='" + username
+ "', userpass='" + userpass + "' WHERE userid='" + userid
+ "'") > 0;
}
}