Socket communication in Java enables communication between two endpoints over a network. There are two main types of sockets: TCP sockets and UDP sockets. Let's explain both types with examples: TCP Socket Communication: 1. **Server Side**: - The server creates a `ServerSocket` object to listen for incoming connections on a specific port. - When a client connects, the server accepts the connection and creates a `Socket` object to communicate with the client. - The server reads from and writes to the socket's input and output streams to communicate with the client. import java.io.*; import java.net.*; public class TCPServer { public static void main(String[] args) throws IOException { ServerSocket serverSocket = new ServerSocket(12345); System.out.println("Server started. Waiting for client..."); Socket clientSocket = serverSocket.accept(); System.out.println("Client connected."); BufferedReader in = new Bu
File I/O Classes Reading
1. File Class:
- Represents a file or directory path in the file system.
- Provides methods for file manipulation and querying file attributes.
File file = new File("example.txt");
if (file.exists()) {
System.out.println("File exists!");
} else {
System.out.println("File does not exist!");
}
2. FileInputStream:
- Reads raw bytes from a file input stream.
- Suitable for reading binary data from files.
try (FileInputStream fis = new FileInputStream("example.txt")) {
int byteRead;
while ((byteRead = fis.read()) != -1) {
System.out.print((char) byteRead);
}
} catch (IOException e) {
e.printStackTrace();
}
3. BufferedReader:
- Reads text from a character-input stream efficiently by buffering characters.
try (BufferedReader br = new BufferedReader(new FileReader("example.txt"))) {
String line;
while ((line = br.readLine()) != null) {
System.out.println(line);
}
} catch (IOException e) {
e.printStackTrace();
}
4. FileReader:
- Reads character files using the default character encoding.
try (FileReader fr = new FileReader("example.txt")) {
int character;
while ((character = fr.read()) != -1) {
System.out.print((char) character);
}
} catch (IOException e) {
e.printStackTrace();
}
5. Scanner:
- Parses primitive types and strings from the input stream.
- Simplifies the process of reading user input or file contents.
try (Scanner scanner = new Scanner(new File("example.txt"))) {
while (scanner.hasNextLine()) {
System.out.println(scanner.nextLine());
}
} catch (FileNotFoundException e) {
e.printStackTrace();
}
These examples demonstrate how to use various file I/O classes to read data from files in Java.
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