Java by API/java.io/BufferedReader

BufferedReader: readLine()

 
/*
 * Output:
 */
import java.io.BufferedReader;
import java.io.FileReader;
public class MainClass {
  public static void main(String args[]) {
    try {
      FileReader fr = new FileReader(args[0]);
      BufferedReader br = new BufferedReader(fr);
      String s;
      while((s = br.readLine()) != null)
        System.out.println(s);
      fr.close();
    }
    catch(Exception e) {
      System.out.println("Exception: " + e);
    }
  }
}

new BufferedReader(FileReader fileReader)

 
/*
 * Output:
 */
import java.io.BufferedReader;
import java.io.FileReader;
public class MainClass {
  public static void main(String args[]) {
    try {
      FileReader fr = new FileReader(args[0]);
      BufferedReader br = new BufferedReader(fr);
      String s;
      while((s = br.readLine()) != null)
        System.out.println(s);
      fr.close();
    }
    catch(Exception e) {
      System.out.println("Exception: " + e);
    }
  }
}

new BufferedReader(InputStreamReader input)

 
/*
 * Output:
 */
import java.io.BufferedReader;
import java.io.InputStreamReader;
public class MainClass {
  public static void main(String args[]) {
    try {
      InputStreamReader isr = new InputStreamReader(System.in);
      BufferedReader br = new BufferedReader(isr);
      while (true) {
        System.out.print("Radius? ");
        String str = br.readLine();
        double radius;
        try {
          radius = Double.valueOf(str).doubleValue();
        } catch (NumberFormatException nfe) {
          System.out.println("Incorrect format!");
          continue;
        }
        if (radius <= 0) {
          System.out.println("Radius must be positive!");
          continue;
        }
        double area = Math.PI * radius * radius;
        System.out.println("Area is " + area);
        return;
      }
    } catch (Exception e) {
      e.printStackTrace();
    }
  }
}

new BufferedReader(Reader in)

 

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.URL;
public class Main {
  public static void main(String[] args) throws Exception {
    URL url = new URL("http://localhost:1776");
    BufferedReader in = new BufferedReader(new InputStreamReader(url.openStream()));
    String line;
    while ((line = in.readLine()) != null) {
      System.out.println(line);
    }
    in.close();
  }
}