How do you read multiple files in a loop in java?

How do you read multiple files in a loop in java?

Look at the Java File and Scanner class. You can use the file class to create an object based on a directory then call listFiles() on the File object to get the files. You can then loop through these files and use the Scanner class to read each file line by line Scanner.

How read and write simultaneously in java?

Your best bet here is likely going to be reading in the file into memory (Something like a StringBuilder ) and writing what you want your output file to look like into the StringBuilder . After you’re done reading in the file completely, you’ll then want to write the contents of the StringBuilder to the file.

How do you perform reading and writing files in java explain with example?

Java FileWriter and FileReader classes are used to write and read data from text files (they are Character Stream classes). It is recommended not to use the FileInputStream and FileOutputStream classes if you have to read and write any textual information as these are Byte stream classes.

How do you write multiple data from a text file in java?

boolean append = true; String filename = “/path/to/file”; BufferedWriter writer = new BufferedWriter(new FileWriter(filename, append)); // OR: BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(filename, append))); writer. write(line1); writer. newLine(); writer.

How do I read multiple files?


  1. Import modules.
  2. Add path of the folder.
  3. Change directory.
  4. Get the list of a file from a folder.
  5. Iterate through the file list and check whether the extension of the file is in . txt format or not.
  6. If text-file exist, read the file using File Handling.

How do I compile multiple Java files in command prompt?

2. Compile multiple Java source files

  1. Compile three source files at once, type: javac
  2. Compile all source files whose filenames start with Swing: javac Swing*.java.
  3. Compile all source files:

How read data from one file and write into another file in Java?

Simple Program

  1. import*;
  2. class file1 {
  3. public static void main(String arg[]) {
  4. File inf = new File(“in.dat”);
  5. File outf = new File(“out.dat”);
  6. FileReader ins = null;
  7. FileWriter outs = null;
  8. try {

What is difference between Fileinputstream and FileOutputStream?

InputStream Read data from the source once at a time. 2. OutputStream Write Data to the destination once at a time.

What is multithreading in Java?

Multithreading is a Java feature that allows concurrent execution of two or more parts of a program for maximum utilization of CPU. Each part of such program is called a thread. So, threads are light-weight processes within a process.

How we can read and write contents of a file in Java?

Reading and Writing text file in Java

  1. BufferedReader in = new BufferedReader(Reader in, int size);
  2. public class BufferedWriter extends Writer.
  3. public class FileWriter extends OutputStreamWriter.

What is the difference between BufferedWriter and FileWriter?

FileWriter writes directly into Files and should be used only when the number of writes is less. BufferedWriter: BufferedWriter is almost similar to FileWriter but it uses internal buffer to write data into File. So if the number of write operations is more, the actual IO operations are less and performance is better.

How do you make a multiline string in Java?

If you want your string to span multiple lines, you have to concatenate multiple strings: String myString = “This is my string” + ” which I want to be ” + “on multiple lines.”; It gets worse though. If you want your string to actually contain new lines, you need to insert \n after each line.

How to read a file in Java?

Here are some of the many ways of reading files: Using BufferedReader: This method reads text from a character-input stream. It does buffering for efficient reading of… Using FileReader class: Convenience class for reading character files. The constructors of this class assume that the… Using

How to write a text file in Java?

To write a text file in Java, use FileWriterinstead of FileReader, and BufferedOutputWriterinstead of BufferedOutputReader. Simple eh? Here’s an example program that creates a file called ‘temp.txt’ and writes some lines of text to it.

What is the difference between FileReader and filewriter in Java?

FileReader – It is a built-in class in java that allows reading data from a file. This class has implemented based on the character stream. The FileReader class provides a method read () to read data from a file character by character. FileWriter – It is a built-in class in java that allows writing data to a file.

What is the difference between write () and read () methods in Java?

The write () method writes a valid character sequence – either a String, a char []. Additionally, it can write a single char represented as an int. The read () method reads and returns character-by-character, allowing us to use the read data in a while loop for example.