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AjaxLookupServlet.javaAPI DocExample5688Wed Apr 05 20:05:42 BST 2006com.oreilly.ajax.servlet

AjaxLookupServlet

public class AjaxLookupServlet extends HttpServlet

Fields Summary
private static final long
serialVersionUID
Constructors Summary
Methods Summary
private java.util.ListcompleteUsername(java.lang.String username)

        Connection con = DatabaseConnector.getConnection();
        ArrayList usernameList = new ArrayList();
        ResultSet result = null;
        try
        {
            Statement select = con.createStatement();
            result = select
                    .executeQuery("SELECT USERNAME from USERS where USERNAME like '"
                            + username + "%';");
            while (result.next())
            {
                usernameList.add(result.getString("username"));
            }
        } catch (SQLException e){}
        finally{
            if(con != null)
            {
                try{
                    con.close();
                }catch(SQLException e){}
                
            }
        }
        return usernameList;
public voiddoGet(javax.servlet.http.HttpServletRequest req, javax.servlet.http.HttpServletResponse res)


         
              
    
        String responseString = null;
        String username = req.getParameter("username");
        String type = req.getParameter("type");

        int typeInt = Integer.parseInt(type);

        if (username != null)
        {
            switch (typeInt)
            {

            case 1:
                List list = completeUsername(username);
                responseString = JSONUtil.buildJSONArray(list, "usernames");

                break;
            case 2:
                HashMap customer = getCustomerInfo(username);
                responseString = JSONUtil.buildJSON(customer, "customer");
                break;

            case 3:
                responseString = getAllUsers();

                System.out.println("response: " + responseString);
            }
        }
        if (responseString != null)
        {
            res.setContentType("text/xml");
            res.setHeader("Cache-Control", "no-cache");
            res.getWriter().write(responseString);
        } else
        {
            // If key comes back as a null, return a question mark.
            res.setContentType("text/xml");
            res.setHeader("Cache-Control", "no-cache");
            res.getWriter().write("?");
        }
private java.lang.StringgetAllUsers()

        Connection con = DatabaseConnector.getConnection();
        ResultSet result = null;
        StringBuffer returnSB = null;
        try
        {
            Statement select = con.createStatement();
            result = select.executeQuery("SELECT USERNAME from USERS;");
            returnSB = new StringBuffer();
            while (result.next())
            {
                returnSB.append(result.getString("username") + ",");
            }
            returnSB.deleteCharAt(returnSB.length() - 1);
        } catch (SQLException e)
        {
            // You could pop up a window with AJAX to let users know there is a
            // problem.
        } finally{
            if(con != null)
            {
                try{
                    con.close();
                }catch(SQLException e){}
                
            }
        }
        return returnSB.toString();
private java.util.HashMapgetCustomerInfo(java.lang.String username)

        Connection con = DatabaseConnector.getConnection();
        ResultSet result = null;
        HashMap map = new HashMap();
        // preload the map with empty strings.
        map.put("email", "");
        map.put("name", "");
        map.put("address", "");
        map.put("city", "");
        map.put("state", "");
        map.put("zipcode", "");

        try
        {
            Statement select = con.createStatement();
            result = select
                    .executeQuery("SELECT * from USERS where USERNAME = '"
                            + username + "';");
            String name = null;
            String value = null;
            if (result != null && result.next())
            {
                ResultSetMetaData metaData = result.getMetaData();
                for (int i = 1; i <= metaData.getColumnCount(); i++)
                {
                    name = metaData.getColumnName(i);
                    value = result.getString(name);
                    loadMap(map, name, value);
                }
            }
        } catch (SQLException e)
        {
            return map;
        } finally{
            if(con != null)
            {
                try{
                    con.close();
                }catch(SQLException e){}
                
            }
        }
        return map;
private voidloadMap(java.util.HashMap map, java.lang.String key, java.lang.String value)

        map.put(key, value == null ? "?" : value);