I cannot get my out string to print to my .jsp file after the post method is run. Below are my .java and .jsp files. I have removed the code there as by this time I know what I was trying was far from intuitive. I have simply left comments where I know the two respective lines of code need to go. I am simply trying to print the string "out" in my .jsp file after the servlet has executed the SQL command.
EDIT: I finally have all of my output going to the JSP page. The only problem I'm having now is that my less-than-ideal method of storing my query results in the out string is leading to my output being one long line of results, instead of a nice spacing or table. I know I would be better off looping through the results in a table in the jsp, but I can't seem to get that to work either.
dbServlet.jsp
<?xml version = "1.0"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<!-- dbServlet.html -->
<html xmlns = "http://www.w3.org/1999/xhtml">
<head>
<title>MySQL Servlet</title>
<style type="text/css">
body{background-color: green;}
</style>
</head>
<body>
<h1>Hello World!</h1>
<h2>This is the MySQL Servlet</h2>
<form action = "/database/database" method = "post">
<p>
<label>Enter your query and click the button to invoke a MySQL Servlet
<input type = "text" name = "query" />
<input type = "submit" value = "Run MySQL Servlet" />
</label>
</p>
</form>
<hr>
<%= request.getAttribute("queryResults") %>
</body>
</html>
databaseServlet.java
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.sql.*;
@SuppressWarnings("serial")
public class databaseServlet extends HttpServlet {
private Connection conn;
private Statement statement;
public void init(ServletConfig config) throws ServletException {
try {
Class.forName(config.getInitParameter("databaseDriver"));
conn = DriverManager.getConnection(
config.getInitParameter("databaseName"),
config.getInitParameter("username"),
config.getInitParameter("password"));
statement = conn.createStatement();
}
catch (Exception e) {
e.printStackTrace();
}
}
protected void doPost (HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String out = "\n";
String query = request.getParameter("query");
if (query.toString().toLowerCase().contains("select")) {
//SELECT Queries
try {
ResultSet resultSet = statement.executeQuery(query.toString());
ResultSetMetaData metaData = resultSet.getMetaData();
int numberOfColumns = metaData.getColumnCount();
for(int i = 1; i<= numberOfColumns; i++){
out = out + "\t" + metaData.getColumnName(i) + "\n";
}
out = out + "\n";
while (resultSet.next()){
for (int i = 1; i <= numberOfColumns; i++){
out = out + "\t" + resultSet.getObject(i) + "\n";
}
out = out + "\n";
}
}
catch (Exception f) {
f.printStackTrace();
}
}
else if (query.toString().toLowerCase().contains("delete") || query.toLowerCase().contains("insert")) {
//DELETE and INSERT commands
try {
conn.prepareStatement(query.toString()).executeUpdate(query.toString());
out = "\t\t Database has been updated!";
}
catch (Exception l){
l.printStackTrace();
}
}
else {
//Not a valid response
out = "\t\t Not a valid command or query!";
}
request.setAttribute("queryResults", out);
RequestDispatcher dispatcher = request.getRequestDispatcher("/dbServlet.jsp");
dispatcher.forward(request, response);
}
}
