search string in all files in a directory java code example

Example 1: java get all files in directory

public static List<String> mapFolder(String path, boolean includeEmptyFolders) {
    	List<String> map = new ArrayList<String>();
    	List<String> unmappedDirs = new ArrayList<String>();
    	File[] items = new File(path).listFiles();

    	if (!path.substring(path.length() - 1).equals("/")) {
    		path += "/";
    	}
    		
    	if (items != null) {
	    	for (File item : items) {
	    		if (item.isFile())
	    				map.add(path+item.getName());
	    		else
	    			unmappedDirs.add(path+item.getName());
	    	}
	    	
	    	if (!unmappedDirs.isEmpty()) {
	    		for (String folder : unmappedDirs) {
	    			List<String> temp = mapFolder(folder, includeEmptyFolders);
	    			if (!temp.isEmpty()) {
	    				for (String item : temp)
	    					map.add(item);
    				} else if (includeEmptyFolders == true)
    					map.add(folder+"/");
	    		}
	    	}
    	}
    	return map;
    }

Example 2: java search file in folder

import java.io.File;

public class Main {
   public static void main(String[] argv) throws Exception {
      File dir = new File("directoryName");
      String[] children = dir.list();
      
      if (children == null) {
         System.out.println("does not exist or 
         is not a directory");
      } else {
         for (int i = 0; i < children.length; i++) {
            String filename = children[i];
            System.out.println(filename);
         }
      }
   }
}