FileIO

src/FilesIO/FileWriting.java

+package FilesIO;
+
+import java.io.BufferedWriter;
+import java.io.File;
+import java.io.FileWriter;
+import java.io.IOException;
+import java.time.LocalTime;
+
+public class FileWriting {
+
+	public static void main(String[] args) {
+		File f = new File("C:/tmp/mylog.txt");
+		FileWriter fw;
+		try {
+			fw = new FileWriter(f);
+			BufferedWriter bw = new BufferedWriter(fw);
+			for (int i=0; i <1000; i++) {
+				bw.write(LocalTime.now().toString()+ "\n");
+			}
+			bw.close();
+			fw.close();
+			System.out.println("wrote " + f);
+		} catch (IOException e) {
+			e.printStackTrace();
+		}
+		
+
+	}
+
+}

src/FilesIO/ReadDirectory.java

+package FilesIO;
+// Write a Java program to get a list of all file/directory names
+// could extend to solve the problem of importing and renaming
+// packages as mentioned by Svetlana at the start of the course
+public class ReadDirectory {
+
+	public static void main(String[] args) {
+		// 1. get current directory and print it out
+		
+		// 2. list all files in the directory
+		// store all files in an array of files
+		
+		// 3. print file extensions that exist in the directory
+        // ignore directories and files that start with .
+		
+	}
+
+}

src/FilesIO/ReadDirectorySolution.java

+package FilesIO;
+import java.io.File;
+import java.util.ArrayList;
+import java.util.Date;
+import java.util.Set;
+import java.util.TreeSet;
+
+// Write a Java program to get a list of all file/directory names
+public class ReadDirectorySolution {
+
+	public static void main(String[] args) {
+		
+		// get current directory
+		String userDirectory = new File("").getAbsolutePath();
+		System.out.println("my directory: "+ userDirectory);
+		
+		// list all files in the directory
+		// store all files in an array of files
+		System.out.print("File names: ");
+        String[] fileList = new File(userDirectory).list();
+        ArrayList<File> files = new ArrayList<File>();
+        for (String name:fileList){
+            System.out.print(name+ " ");
+            files.add(new File(name));
+        }
+        System.out.println();
+        
+		// print file extensions that exist in the directory
+        // ignore directories and files that start with.
+        System.out.print("File extensions: ");
+        Set <String> ext = new TreeSet<String>();
+        for (File fi: files) {
+        	if (fi.isDirectory()) {
+        		continue;
+        	}
+        	else if (!fi.getName().startsWith(".") && fi.getName().contains(".")) {
+        		ext.add(fi.getName().split("\\.")[1]);
+        	}			
+		}
+        System.out.println(ext);
+
+	}
+
+}