<html>
<head>
<title>JSP Form</title>
<style>
</style>
</head>
<body>
<form action="TestFileHandling.jsp" method="post">
<fieldset>
<legend>User Information</legend>
<label for="question">Question</label>
<input type="text" name="question"/><br/>
<input type="submit" value="submit">
</fieldset>
</form>
</body>
</html>
The above is a simple form that lets the user enter a question before sending it.
<%@page import="myPackage.FileReaderWriter" %>
<%@page import="java.util.Vector" %>
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
"http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<%
Vector<String[]> v = new Vector<String[]>();
String[] str1 = {request.getParameter("question")};
v.addElement(str1);
FileReaderWriter.saveVectorToFile(v, "MyTestFile.txt");
%>
<%
Vector<String[]> vec = FileReaderWriter.readFileToVector("MyTestFile.txt");
for (int i = 0; i < vec.size(); i++) {
out.print("|");
for (int j = 0; j < vec.elementAt(i).length; j++) {
out.print(vec.elementAt(i)[j] + "|");
}
%>
<br>
<%
}
%>
</body>
</html>
This part takes the question entered and saves it to a text file and then opens the file to display whatever is inside.
All this is done through the following java code:
package myPackage;
import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.util.Vector;
public class FileReaderWriter {
public static void saveVectorToFile(Vector<String[]> v, String sFileName) {
try {
// Create a new file writer
FileWriter writer = new FileWriter(sFileName);
// Loop through all the elements of the vector
for (int i = 0; i < v.size(); i++) {
// Capture the index of the last item of each array
int lastIndex = v.elementAt(i).length - 1;
// Loop through all the items of the array, except
// the last one.
for (int j = 0; j < lastIndex; j++) {
// Append the item to the file.
writer.append(v.elementAt(i)[j]);
// Append a comma after each item.
writer.append(',');
}
// Append the last item.
writer.append(v.elementAt(i)[lastIndex]);
// Append a new line character to the end of the line
// (i.e. Start new line)
writer.append('\n');
}
// Save and close the file
writer.flush();
writer.close();
}
// Catch the exception if an Input/Output error occurs
catch (IOException e) {
e.printStackTrace();
}
}
public static Vector<String[]> readFileToVector(String sFileName) {
// Initialise the BufferedReader
BufferedReader br = null;
// Create a new Vector. The elements of this Vector are String arrays.
Vector<String[]> v = new Vector<String[]>();
try {
// Try to read the file into the buffer
br = new BufferedReader(new FileReader(sFileName));
// Initialise a String to save the read line.
String line = null;
// Loop to read all the lines
while ((line = br.readLine()) != null) {
// Convert the each line into an array of Strings using
// comma as a separator
String[] values = line.split(",");
// Add the String array into the Vector
v.addElement(values);
}
}
// Catch the exception if the file does not exist
catch (FileNotFoundException ex) {
ex.printStackTrace();
}
// Catch the exception if an Input/Output error occurs
catch (IOException ex) {
ex.printStackTrace();
}
// Close the buffer handler
finally {
try {
if (br != null)
br.close();
} catch (IOException ex) {
ex.printStackTrace();
}
}
// return the Vector
return v;
}
}
My problem is that although everything seems to be working, everytime I enter a new question the old one in the text file gets overwritten. Is there a way I can fix this so that every time I enter a new question in the form, it will get added to the textfile along with all the others instead of constantly overwritting it? Thanks for any information or help.
