file

Isn’t annoying to remember all the mumbo jumbo just to open a file and what about reading a file into a string, colloquially known as slurping.

package com.java.files;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;

public class files {

	// open resource as BufferedReader
	// Example usage :
	//   BufferedReader br = open("file_name.txt");
	//    .... do something .. br.readLine() ...
	//   br.close();
	public static BufferedReader open(Class ref, String file_name) throws FileNotFoundException {
		InputStream stream = ref.getResourceAsStream(file_name);
		if (stream == null) throw new FileNotFoundException("Can't locate : " + file_name);
		BufferedReader br = new BufferedReader(new InputStreamReader(stream));
		return br;
	}
	
	// open file as BufferedReader
	public static BufferedReader open(String file_name) throws FileNotFoundException {
		BufferedReader br = new BufferedReader(new FileReader(file_name));
		return br;
	}

	public static void write2file(String file_name, String str) throws IOException {
		BufferedWriter wr = new BufferedWriter(new FileWriter(file_name));
		wr.write(str);
		wr.close();
	}

	
	
	//internal function to process a file for the slurps...
	private static String slurpit(BufferedReader br, String skip, String eol) throws Exception {
		StringBuilder sb = new StringBuilder();
		String line;
		while( (line = br.readLine() ) != null ) {
			if(skip == null || (skip != null && !line.matches(skip)) ) {
				if (eol == null) { sb.append( line ); } else { sb.append(line + eol); };
			}	
		};
		br.close();
		return sb.toString();
	}
	
	//read a whole file into a string, but skip lines that match a regex
	public static String slurp_skip(String file_name, String skip, String eol) throws Exception {
		BufferedReader br = open(file_name);
		return slurpit(br, skip, eol);
	}
	
		
	//read a whole file into a string, from a "jar" directories i.e. relative. 
	// but skip lines that match a regex
	public static String slurp_skip(Class ref, String file_name, String skip, String eol) throws Exception {
		BufferedReader br = open(ref,file_name);//read resource
		return slurpit(br, skip, eol);
	}
	
	//just read the whole file in a string
	public static String slurp(String file_name) throws Exception {
		return slurp_skip(file_name, null, null);
	}
	
	public static String slurp(Class ref, String file_name) throws Exception {
		return slurp_skip(ref, file_name, null, null);
	}
	
	public static String slurp(Class ref, String file_name, String eol) throws Exception {
		return slurp_skip(ref, file_name, null, eol);
	}
	
	public static String slurp(String file_name, String eol) throws Exception {
		return slurp_skip(file_name, null, eol);
	}

}

Example usage :

//print the first line of a file
BufferedReader br = open("file_name.txt");
System.out.println( br.readLine() )
br.close();

//print a file
System.out.println( slurp("file_name.txt") )


//print a file from directory relative to the .jar root or resources dir
System.out.println( slurp(this.getClass(), "file_name.txt") )