Add copyright statement in all source files.

You have completed you development for a large project and QA finished the tests as well, everything works perfectly,so you may decide to celebrate a little bit. Before you come out a great plan, your manager come over and told you there is some tedious thing to do: You need to add a copyright statement to each and every source code file. Jus like many people, you may start quickly estimating how many files you need to CTRL+C and CTRL+V, and then do a integration test before you can commit your change.If you are a hard-working employee, you may your change right way, but if you are a ‘lazy’ programmer, you may try something differently:

As you are a programmer, you are good at coding, why not write a program to do the job, here is the jave code:

Step 1: Find out all the files need to be updated.

import java.io.File;
import java.util.ArrayList;
import java.util.List;

public class ListFilesUtil {
	public List <String> listFilesUnderDirectories(String directoryName) {
		List<String> fileList = new ArrayList<>();
		File directory = new File(directoryName);
		File[] fList = directory.listFiles();
		for (File file : fList) {
			if (file.isFile() && file.getAbsolutePath().endsWith(".js")) {
				fileList.add(file.getAbsolutePath()); 
			} else if (file.isDirectory()) {
				fileList.addAll(listFilesUnderDirectories(file.getAbsolutePath()));
			}
		}
		return fileList;
	}
}

Step2: For each file, re-write it with the copy right content

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.util.List;

public class RewriteFile {

	public static void main(String[] args) {
		
		String targetDirectory = "target_directory"; 
		RewriteFile rf = new RewriteFile();
		String licence =  rf.readFile("copyright.txt") ;
		ListFilesUtil util = new ListFilesUtil(); 
		List <String> fileList = util.listFilesUnderDirectories(targetDirectory);
		
		fileList.forEach(file->{
			 rf.rewriteFile(file, licence);
		});
	}

	public void rewriteFile(String fileName, String licence) {

		try {
			
			StringBuffer sb = new StringBuffer();
			try {
				FileReader fr = new FileReader(fileName);
				BufferedReader br = new BufferedReader(fr);
				String line = "";
				
				line = br.readLine();
				while (line != null) {
					sb.append(line+"\n");
					line = br.readLine();
				}
				br.close();
			} catch (FileNotFoundException e) {
				System.out.println("File was not found!");
			} catch (IOException e) {
				System.out.println("No file found!");
			}
			String newContext = licence + "\n"+  sb.toString();
			
			FileWriter fw = new FileWriter(fileName, false);
			BufferedWriter bw = new BufferedWriter(fw);
			bw.write(newContext);
		 
			bw.close();
		} catch (FileNotFoundException e) {
			System.out.println("Error1!");
		} catch (IOException e) {
			System.out.println("Error2!");
		}
	}

	public String readFile(String fileName) {

		StringBuffer sb = new StringBuffer();
		try {
			FileReader fr = new FileReader(fileName);
			BufferedReader br = new BufferedReader(fr);
			String line = "";

			while ((line = br.readLine()) != null) {
				sb.append(line +"\n");
			}
			br.close();
		} catch (FileNotFoundException e) {
			System.out.println("File was not found!");
		} catch (IOException e) {
			System.out.println("No file found!");
		}
		return sb.toString();
	}
}