J2ee Tutorial 13 :-Parsing csv in j2ee

// Parsing csv in j2ee 

Step1 ;- Create a dynamic web project

Step2 :- Chang the content in the web.xml as given bellow

<?xml version="1.0" ?>
<web-app version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee   
http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">

    <servlet>
      <servlet-name>CSVReader</servlet-name>
      <servlet-class>web.prac.CSVReader</servlet-class>//our reader servlet
      <init-param>
        <param-name>jsp</param-name>
        <param-value>/csvRenderer.jsp</param-value>//declarring the jsp to be loaded
      </init-param>
    </servlet>
    <servlet-mapping>
      <servlet-name>CSVReader</servlet-name>
      <url-pattern>/CSVReader/*</url-pattern>
    </servlet-mapping>

</web-app>

Step 3:- Create a bean which will store the data andparse the csv

/*
 * Created on 25-Jan-2005
 *
 */
package web.prac;

import java.util.*;
import java.io.*;

public class CSVBean {
    private int rowCount; // Number of rows (excluding header row)

    private int fieldCount; // Number of fields in each row

    private String[] headers; // Field names (assumed to be in first row)

    private List rows = new ArrayList(); // The data

    public CSVBean() {
        // Must have a no-argument constructor as a bean.
    }

    public void parseFile(File f) {

        BufferedReader br;
        try {
            br = new BufferedReader(new FileReader(f));
        } catch (FileNotFoundException e) {
            e.printStackTrace();
            return;
        }
        String line;
        boolean firstRow = true;
        try {
            while ((line = br.readLine()) != null) {
                if (firstRow) {
                    headers = tokenize(line);
                    setFieldCount(headers.length);
                    firstRow = false;
                } else {
                    String[] row = tokenize(line);
                    rows.add(row);   
                    rowCount++;
                }
            }
        } catch (IOException e1) {
            e1.printStackTrace();
            return;
        }
    }

    protected String[] tokenize(String line) {
        StringTokenizer st = new StringTokenizer(line, ",");
        int tokenCount = st.countTokens();
        String[] record = new String[tokenCount];
        for (int i = 0; i < tokenCount; i++) {
            record[i] = (String) st.nextToken();
        }
        return record;
    }

    public int getFieldCount() {
        return fieldCount;
    }

    public void setFieldCount(int fieldCount) {
        this.fieldCount = fieldCount;
    }

    public String[] getHeaders() {
        return headers;
    }

    public void setHeaders(String[] headers) {
        this.headers = headers;
    }

    public int getRowCount() {
        return rowCount;
    }

    public void setRowCount(int rowCount) {
        this.rowCount = rowCount;
    }

    public List getRows() {
        return rows;
    }

    public void setRows(List rows) {
        this.rows = rows;
    }
   
    public String toString() {
        StringBuffer sb = new StringBuffer();
        sb.append("Headers: ");
        addStringArray(headers, sb);
        Iterator it = rows.iterator();
        int rowCount = 0;
        while (it.hasNext()) {
            rowCount++;
            sb.append("Row " + rowCount + ": ");
            String[] row = (String []) it.next();
            addStringArray(row, sb);
        }
        return sb.toString();
    }
   
    protected StringBuffer addStringArray(String[] array, StringBuffer buffer) {
        for (int i = 0; i < array.length; i++) {
            buffer.append(array[i] + ",");
        }
        buffer.append("\n");
        return buffer;
    }
   
}

Step 4 :- Now create the servletwhichcontrols the flow

package web.prac;

import java.io.*;

import javax.servlet.*;
import javax.servlet.http.*;

public class CSVReader extends HttpServlet {
   
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        String path = request.getPathInfo();
        ServletContext context = getServletContext();
        String fullPath = context.getRealPath(path);
        File f = new File(fullPath);
        CSVBean csvBean = new CSVBean();
        csvBean.parseFile(f);
        request.setAttribute("csv", csvBean);
        String jsp = getInitParameter("jsp");
        RequestDispatcher rd = context.getRequestDispatcher(jsp);
        rd.forward(request, response);
    }
   
}

Step5 :- Final output page displaying csv data using scripletes

<html><head><title>CSV File Renderer</title></head>
<jsp:useBean id="csv" scope="request" type="webcert.ch07.ex0703.CSVBean" />
<%@ page import="java.util.*" %>
<body>
<h1>CSV File Presented As HTML Table</h1>
<h2>JSP Syntax Version</h2>
<h3>There are
<jsp:getProperty name="csv" property="rowCount" />
 rows of data, and
 <jsp:getProperty name="csv" property="fieldCount" />
  columns.</h3>
<table border="1">
  <tr>
    <th>&nbsp;</th>
    <% String[] headers = csv.getHeaders();
    for (int i = 0; i < headers.length; i++) { %>
      <th><b><%= headers[i] %></b></th>
    <% } %>
  </tr>
  <% List rows = csv.getRows();
     Iterator it = rows.iterator();
     int rowNumber=0;
     while (it.hasNext()) {
  %>
  <tr>
     <td>Row <%= ++rowNumber %></td>
  <% String[] fields = (String[]) it.next();
    for (int i = 0; i < fields.length; i++) { %>
      <td><%= fields[i] %></td>
    <% } %>
  </tr>
  <% } %>
</table>

</body></html>


Step6 :- Final output page displaying csv data usingjsp standard actions

<html xmlns:jsp="http://java.sun.com/JSP/Page" >
<head><title>CSV File Renderer</title></head>
<jsp:output omit-xml-declaration="true" />
<jsp:directive.page contentType="text/html" />
<jsp:directive.page import="java.util.*" />
<jsp:useBean id="csv" scope="request" type="web.prac.CSVBean" />
<body>
<h1>CSV File Presented As HTML Table</h1>
<h2>JSP Document (XML) Version</h2>
<h3>There are
<jsp:getProperty name="csv" property="rowCount" />
 rows of data, and
 <jsp:getProperty name="csv" property="fieldCount" />
  columns.</h3>
<table border="1">
  <tr>
    <th><![CDATA[&nbsp;]]></th>
    <jsp:scriptlet> String[] headers = csv.getHeaders();
    for (int i = 0; i &lt; headers.length; i++) { </jsp:scriptlet>
      <th><b><jsp:expression>headers[i]</jsp:expression></b></th>
    <jsp:scriptlet>}</jsp:scriptlet>
  </tr>
  <jsp:scriptlet>List rows = csv.getRows();
     Iterator it = rows.iterator();
     int rowNumber=0;
     while (it.hasNext()) {
  </jsp:scriptlet>
  <tr>
     <td>Row <jsp:expression>++rowNumber</jsp:expression></td>
  <jsp:scriptlet>String[] fields = (String[]) it.next();
    for (int i = 0; i &lt; fields.length; i++) { </jsp:scriptlet>
      <td><jsp:expression>fields[i]</jsp:expression></td>
    <jsp:scriptlet> } </jsp:scriptlet>
  </tr>
  <jsp:scriptlet> } </jsp:scriptlet>
</table>
</body></html>