A simple implementation of Java for reading files

This article illustrates a simple and useful way to implement Java reading files. Share with you for your reference. Specific methods are as follows:

This is a simple code to read a file, try to read a log file, and then output.

The main code is as follows:

import java.io.*;
public class FileToString {
   public static String readFile(String fileName) {
    String output = ""; 
    File file = new File(fileName);
    if(file.exists()){
      if(file.isFile()){
        try{
          BufferedReader input = new BufferedReader (new FileReader(file));
          StringBuffer buffer = new StringBuffer();
          String text;
          while((text = input.readLine()) != null)
            buffer.append(text +"/n");
          output = buffer.toString();          
        }
        catch(IOException ioException){
          System.err.println("File Error!");
        }
      }
      else if(file.isDirectory()){
        String[] dir = file.list();
        output += "Directory contents:/n";
        
        for(int i=0; i<dir.length; i++){
          output += dir[i] +"/n";
        }
      }
    }
    else{
      System.err.println("Does not exist!");
    }
    return output;
   }
   public static void main (String args[]){
     String str = readFile("C:/1.txt");
     System.out.print(str);
   }
}

The output results are as follows:

Go Olympics!

Go Beijing!

Go China!

Here the FileReader class opens a file, but it doesn't know how to read a file, which requires the BufferedReader class to provide the ability to read text lines. This combines the functionality of the two classes to open and read files. This is a technique for wrapping flow objects by adding services from one stream to another.

It is also important to note that Java accepts both "/" and "/" when opening a file by path, except that when "/" is used, another "/" is escaped.

I hope this article will be helpful to your Java programming study.