Parsing a String into Paragraphs Using a Regular Expression

This section tells you how to parse the string into the paragraphs using regular expression in Java. In this section, you will learn about the topic through the following program. This program takes a text file from which contents of the file are read and shows the string line-by-line after waiting few some seconds. The time duration for showing string line-by-line are treated through the Thread class and time is fixed in the sleep() method of the Thread class.

Here is the code of the program:


import java.util.regex.*;

import java.io.*;



public class ParseStringInParagraph{

  public static void main(String[] args) throws IOException,InterruptedException{

    BufferedReader in = new BufferedReader(new InputStreamReader(System.in));

    System.out.println("Enter file name: ");

    String filename = in.readLine();

    File file = new File(filename);

    if(!filename.endsWith(".txt")){

      System.out.println("File not in text format.");

      System.exit(0);

    }

    else if(!file.exists()){

      System.out.println("File not found.");

      System.exit(0);

    }

    FileInputStream fstream = new FileInputStream(filename);

    DataInputStream ds = new DataInputStream(fstream);

    BufferedReader br = new BufferedReader(new InputStreamReader(ds));

    Pattern p;

    Matcher m;

    String strLine;

    String inputText = "";

    while((strLine = br.readLine()) != null) inputText = inputText + strLine + "\n";

    String[] paras = Pattern.compile

("(?<=(\r\n|\r|\n))([ \\t]*$)+", Pattern.MULTILINE).split(inputText);

    Thread th = new Thread();

    for(int i=0; i<=paras.length-1; i++){

      System.out.println(paras[i]);

      th.sleep(1500);

    }

  }

}