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Java a program to convert text file to HTML

Write a program to convert  a text file into html file with questions and collapsible answers.

I have a text file which has questions and answers. The file was extracted as a csv file from an sqlite database with ^^^ as a row separator and | as  a column separator.

I read the file using nio  Files. readAllBytes() method.
    
   Path filepath = Paths.get(filename);
    try {
      byte[] byteArray = Files.readAllBytes(filepath);
         String str = new String(byteArray);
      
      }catch(IOException e){
          System.out.println(e.getMessage());
    }

As the method may throw IOException, I have wrapped it in try block.  The method reads the entire file and stores it in a bytearray which is conv   erted to string.

Next to split the content into individual questions, I use string.split(regex) method.  This method splits the string into an array, breaking the string at the occurrence of regex.

Unfortunately, regex has special meaning for ^ symbol. To use ^^^ as a separator, I have to escape this.
String arr[] = str.split("\\^\\^\\^");
Next in a for each loop, I take one question and split it into question and answer using escaped vertical tab as separator.

 for(String qn:arr){
    if(qn.trim()=="")
      continue;
     String qnans[] = qn.split("\\|");
     .....
 }

That's all. Now what is remaining is adding HTML tags. I got a javascript to display a collapsible content which should be included in the HTML body tag.

The code uses buttons of class accordion and hides/shows the adjacent the content.

Here is the complete for loop which does that.


 for(String qn:arr){
            if(qn.trim()=="")
               continue;
            String qnans[] = qn.split("\\|");
       
            writer.write("<hr color='#eee' &gt;");//this will add a horizontal separator
            writer.write(qnans[0]);//question
            
            writer.write("<button class='accordion'>Answer < button>");//button
            writer.write("<div class='panel'>");//collapsible content
            writer.write(qnans[1]);//answer
            writer.write("<div>");            
            
        } 
 
Here is the complete program

import java.nio.file.Files;
import java.nio.file.Paths;
import java.nio.file.Path;
import java.io.IOException;
import java.io.FileWriter;

public class ReadToHTML{
   
        
   public static void writeHtml(String str,String filename)  throws IOException{
        FileWriter writer = new FileWriter(filename);
        str = str.trim();
        writer.write("<html><head><meta charset='utf-8' /><title></title><style>.accordion {  background-color: #eee;  color: #444;  cursor: pointer;  padding: 10px;  width: auto;  border:none;  text-align: left;  outline: none;  font-size: 15px;  transition: 0.4s;}.active, .accordion:hover {  background-color: #ccc; }.panel {  padding: 0 18px;  display: none;  background-color: #ddd;  overflow: hidden;}</style></head><body  >");
         
        String arr[] = str.split("\\^\\^\\^");
        System.out.println("The number of questions is "+arr.length);
        for(String qn:arr){
            if(qn.trim()=="")
               continue;
            String qnans[] = qn.split("\\|");
       
            writer.write("<hr color='#eee'>\n<p>");
            writer.write(qnans[0]);
            writer.write("</p>");
            writer.write("<button class='accordion'>Answer</button>");
            writer.write("<div class='panel'>");
            if(qnans.length<2)
               continue;
       
	    System.out.println("Question is "+qnans[0]);
            System.out.println("Answer is "+qnans[1]);
            writer.write("<p >");
            writer.write(qnans[1]);
            writer.write("</p>");            
            writer.write("</div>");   
        }
        writer.write("<script >var acc = document.getElementsByClassName(\"accordion\");var i;for (i = 0; i < acc.length; i++) {  acc[i].addEventListener(\"click\", function() {    /* Toggle between adding and removing the active class,    to highlight the button that controls the panel */    this.classList.toggle(\"active\");    /* Toggle between hiding and showing the active panel */    var panel = this.nextElementSibling;    if (panel.style.display === \"block\") {      panel.style.display = \"none\";    } else {      panel.style.display = \"block\";    }  });} </script></body></html>");
        writer.close();
  }
   public static void main(String args[]){
      if(args.length<1)
         return;
      String filename = args[0];


    Path filepath = Paths.get(filename);

    try {
      byte[] byteArray = Files.readAllBytes(filepath);
         String str = new String(byteArray);
         System.out.println("The string is "+str);
         writeHtml(str,args[1]);
      }catch(IOException e){
          System.out.println(e.getMessage());
       }
  }
}
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