A Java class that allows writing to files is Class FileWriter. This class is a part of java.io package and extends (inherits from) OutputStreamWriter class.
This class allows us to write character files conveniently. The reason I chose this class is because of the functionality provided by FileWriter class. It allows us to write to a new file, as well as append content to an existing file. Given a filename as a string parameter, it creates the file if it does not already exist. So, the user is not required to explicitly create a new file before writing to it using FileWriter class.
FileWriter class provides several constructors, which are as follows:
1) FileWriter(File file) - takes File object as a parameter, which corresponds to the file, the data is to be written to.
2) FileWriter(File file, boolean append) - takes two parameters: one is the File object to which data is to be written to, and second is a boolean parameter which indicates whether data is to be appended to the file
3) FileWriter(String filename) - takes a string parameter for the filename
4) FileWriter(String filename, Boolean append) - takes two parameters, one for the filename (string) and a Boolean value indicating whether data should be appended to the file or not
Pseudo code:
1. Create a string array and initialize elements of the array with given data
String[] dataArray = new String[4];
dataArray[0] = "1001 Jennifer Ward SUPPLIES 2140.20 BOOKS 5200.10 PAPER 455.23 NORTH Phone";
dataArray[1] = "1003 Athena Andrews SUPPLIES 5155.55 BOOKS 6300.50 PAPER 223.25 SOUTH Email";
dataArray[2] = "1005 Andy Smith SUPPLIES 6155.55 BOOKS 300.50 PAPER 55.55 SOUTH Email";
dataArray[3] = "1006 Robert Stearns SUPPLIES 7255.55 BOOKS 8300.50 PAPER 77.77 SOUTH Phone";
2. Create a File object and pass the filename
File file = new File(“data.txt”);
3. Check if file exits by that name, if it does not create a new file as follows:
file.createNewFile();
4. Create FileWriter object by passing the File object created above
5. In a for loop write each element of the array to the file:
for(int i=0; i<dataArray.length; i++){
writer.write(dataArray[i]); //write the line to file
writer.write("\n"); //write a newline to the file
}
6. Close the writer.
7. Catch any exceptions if thrown
RealCode:
import java.io.*;
class FileWritingExample
{
public static void main(String args[]){
String[] dataArray = new String[4];
dataArray[0] = "1001 Jennifer Ward SUPPLIES 2140.20 BOOKS 5200.10 PAPER 455.23 NORTH Phone";
dataArray[1] = "1003 Athena Andrews SUPPLIES 5155.55 BOOKS 6300.50 PAPER 223.25 SOUTH Email";
dataArray[2] = "1005 Andy Smith SUPPLIES 6155.55 BOOKS 300.50 PAPER 55.55 SOUTH Email";
dataArray[3] = "1006 Robert Stearns SUPPLIES 7255.55 BOOKS 8300.50 PAPER 77.77 SOUTH Phone";
try{
File file = new File("data.txt");
//check if file already exists
if(!file.exists()){
file.createNewFile(); //create a new file if it does not exist
}
//create FileWriter object using File object created above
FileWriter writer = new FileWriter(file);
//write content to file
for(int i=0; i<dataArray.length; i++){
writer.write(dataArray[i]); //write the line to file
writer.write("\n"); //write a newline to the file
}
writer.flush();
writer.close(); //close the writer stream
}catch(IOException ioe){
//display the exception stacktrace
System.out.println("Error while writing to the file");
ioe.printStackTrace();
}
}
}
wilden
java-db2.docx
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