I need to generate a bar chart given the data that is in main. The relative performance of each sorting algorithm with respect to time, number of comparisons, and number of swaps for each data set (e.g., 50,000 –400,000 random integers). Each algorithm will have 5 bars corresponding to the 5 data sets. The height of these bars will depend on the performance of the algorithm for that data set.
I know how to write a bar with normal values like integers but for this I'm not sure because the values for instance comparisons and swaps are not given they are calculated. I just need to know what steps to go about doing that, you can even express them in pseudocode or even just explaining it I don't need the code, I think. Here is the main
public class Main { public static void main(String[] args){ int t= 50000; int t2=100000; int t3=200000; int t4=300000; int t5=400000;
We currently have an application which uses JDBC to connect to the backend database (DB version - 11.2.0.3 ). The application uses a properties file in which the password for the db schema is hardcoded in plain text format. Due to security restrictions we have been asked to make sure the password is encrypted in the file and no direct access is made to the schema using the plain text password. Best options we can use to make this password encrypted both at Oracle DB side and Java side.
i want to generate n number of pdf here n will be some limit according to requirement so ultimately I have to generate more than 1 pdf same time with once running the code I Have some values associated with id i want to print those values with respective id's in pdf format, values can be in database or in some variable , which way i should go... i have some ideas either i can save those values in database and can make a single xml file from database of all records and then divide each node with different different pdf or directly get the values from database and generate the pdf.
At our banking application , there is a requirements to send unique reference number for some payment transaction.How can I do this at Prod while we have three app servers and we don't have DB at our end (front end site)?
I have a basic html form with one user input text box labeled "Enter a number" and a submit button labeled "Create a multiplication table". This is the working with a servlet to display an html formatted multiplication table. Everything else is working fine just the formatting is off; I can't seem to get the top row and far left column to number properly. It should look like this with the top row of numbers beginning with a blank cell and then numbering 1 thru n (depending on what the user selects. The first column should be the same, a blank cell and then 1 thru n. Then the multiplication table should be in the rows/columns of the table. Picture this:
I can't get mine to start with a blank cell in the top left-hand corner, instead it has 1 in that cell and the table starts calculating with 2x2.
I want to retrieve file from database which is stored with blob datatype and i am passing manually id associated with in code. Its not retrieving the file.
public class retrieve_image extends HttpServlet { /** * */ private static final long serialVersionUID = 1L; protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { ResultSet rs = null;
I am trying to make a simple login using netbeans, derby database included in netbeans and tomcat server. I made everything nice and separated: I have a model package with a class called DbConnector that has the following method:
Then i have another class, an userDAODB that has a password check method:
public boolean checkPassword(String user, String password) { try (Connection con = new DbConnector().connect(); Statement stmt = con.createStatement()) { //checks the password in the database
In the main method of this class i tested everything, it works very nice, logs me in, other methods work too, no problem what so ever.But then i go to my servlet:
public class LoginTest extends HttpServlet { public void doPost(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException { String username = request.getParameter("username"); String pass = request.getParameter("pass"); UserDAODB userDAO = new UserDAODB(); boolean authe = userDAO.checkPassword(username, pass);
[code]....
So when i start the webpage and i try to click on the login button I get a NullPointerException com.model. UserDAODB. check Password (User DAODB. java:14) - so line 2 here
I have been googling a bit, i placed the derby.jar and the derbyclient.jar in the lib directory of tomcat, i tried to modify the context.xml of my application, but then it wouldn't even start anymore.
I can insert data to table by using JSP Scriptlet easily but I have a hard time with servlet.
public class UsertToDatabase() { public boolean inserUser(String name, String email, String pwd) throws SQLException { PreparedStatement pstmt = null; boolean flag = false; System.out.println("start"); openConn(); System.out.println("start_1"); if(conn == null) {
[code]....
I am positive that the above code function fine. The problem is whenever I call UserToDB() class inside the servlet, and I got this error: java.lang.ClassNotFoundException: org.postgresql.
Driver which mean that my conn (connection) is not connected to the database but I have ensure to do so by calling openConn() before start the transaction.
ResultSet rs = result.executeQuery(selectsql); int columns = rs.getRow(); while(rs.next()){
[Code].....
I can print out the result correctly, there are three rows of result from the database, but they are shown in one row on the browser, how could i show the result one row after another to let it looks pretty?
I'm working on a project that has two separate components. The first is a back end, that will do most of the heavy lifting, the other part is a front end GUI. The GUI will include the back end into it's project as an imported JAR file.
I need to be able to keep these two decoupled, as I might be writing different front ends using the same back end. The challenge in front of me (well one of many) is how to pass messages from the back end to the GUI so I can report things that are happening.
For example, if i call method FOO, FOO might do several different things; connect to a database, divide by zero, solve world hunger. I want to be able to either tie a JTextArea , or another component (or multiple components) to this stack of information, or at the very least, have something listening for this information, and when I see that my back end reports something, my front end is quickly aware of this information, and then I can process it and inform the user of the front end.
It would also be useful to be able to send a message from front end to back end , so perhaps the back end might learn that the front end user is unhappy and would like to stop running the current query.
If I change the servlet and have "request.getRequestDispatcher("/pages/ViewCompletedWWDocs.jsp").forward(request, response);" un commented, I get exception "java.lang.IllegalStateException: Cannot forward a response that is already committed".
I'm working on a consulting training project to create a eCommerce online shopping application. Nothing big, just something functional and simple. That's why I want to structure it with the easiest maintainability possible. I've already ironed out the the database entities and how they'll relate to one another and even managed to establish connection to the database from my java application class. NOW I need to configure a user session on the web.xml, from what I've learned so far in my consulting, I can easily use jsp and servlets to have httpsession objects receive and send the information needed to and from the database, but the question is, how many do I need for a client's session?
Would maintainability be easier if I divide each entity's class actions to different servlets(a customer servlet, order servlet, product servlet, etc...), or can a single servlet handle an entire session without any complication?
My query retrieves more than 5000 records from Oracle database. I want to display the records 100 per page. I know it is called pagination. Any detailed styp-by-guide or tutorial or example available?
i am newbie to servlet and m working on a project like online shopping. I have list of data items in my database and i am able to fetch and display the data from database but i want to know that how can i store these data items in ServletContext so that i can use use it frequently in other pages.
I am trying to display rows from my database from servlet by passing it to a JSP, but nothing is displayed. I checked the syntax and even the source of the page shows that it gets the data but the rows are not displayed!
