Java/File Input Output/Scanner

new Scanner(new BufferedReader(new FileReader("xanadu.txt")))

   <source lang="java">

/*

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*
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* are met:
*
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*     documentation and/or other materials provided with the distribution.
*
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*     contributors may be used to endorse or promote products derived
*     from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
* IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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import java.io.BufferedReader; import java.io.FileReader; import java.io.IOException; import java.util.Scanner; public class ScanXan {

 public static void main(String[] args) throws IOException {
   Scanner s = null;
   try {
     s = new Scanner(new BufferedReader(new FileReader("xanadu.txt")));
     while (s.hasNext()) {
       System.out.println(s.next());
     }
   } finally {
     if (s != null) {
       s.close();
     }
   }
 }

}

 </source>
   
  
 
  

Perform the conversions after parsing the String

   <source lang="java">

import java.io.File; import java.util.Scanner; public class Main {

 static void parseLine(String line) {
   Scanner lineScanner = new Scanner(line);
   lineScanner.useDelimiter("\\s*,\\s*");
   String name = lineScanner.next();
   int age = lineScanner.nextInt();
   boolean isCertified = lineScanner.nextBoolean();
   System.out.println("It is " + isCertified + " that " + name + ", age " + age
       + ", is certified.");
 }
 public static void main(String[] args) throws Exception {
   Scanner scanner = new Scanner(new File("fileName"));
   scanner.useDelimiter(System.getProperty("line.separator"));
   while (scanner.hasNext()) {
     parseLine(scanner.next());
   }
   scanner.close();
 }

}

 </source>
   
  
 
  

Read file using Scanner class

   <source lang="java">

import java.io.File; import java.util.Scanner; public class Main {

 public static void main(String[] args) throws Exception{
   File file = new File("data.txt");
   Scanner scanner = new Scanner(file);
   while (scanner.hasNextLine()) {
     String line = scanner.nextLine();
     System.out.println(line);
   }
 }

}

 </source>
   
  
 
  

Read in the current contents of the java.net homepage

   <source lang="java">

import java.net.URL; import java.net.URLConnection; import java.util.Scanner; public class Main {

 public static void main(String[] args) throws Exception {
   URLConnection connection = new URL("http://java.net").openConnection();
   String text = new Scanner(connection.getInputStream()).useDelimiter("\\Z").next();
 }

}

 </source>
   
  
 
  

Read user input from console using Scanner class

   <source lang="java">

import java.util.Scanner; public class Main {

 public static void main(String[] args) {
   Scanner scanner = new Scanner(System.in);
   System.out.print("Username: ");
   String username = scanner.nextLine();
   System.out.print("Password: ");
   String password = scanner.nextLine();
   System.out.print("What is 2 + 2: ");
   int result = scanner.nextInt();
   if (username.equals("admin") && password.equals("secret") && result == 4) {
     System.out.println("Welcome");
   } else {
     System.out.println("Invalid username or password!");
   }
 }

}

 </source>
   
  
 
  

Scanning text with java.util.Scanner

   <source lang="java">

import java.io.BufferedReader; import java.io.File; import java.io.FileReader; public class Main {

 private static void readFile(String fileName) throws Exception {
   File file = new File(fileName);
   FileReader reader = new FileReader(file);
   BufferedReader in = new BufferedReader(reader);
   String string;
   while ((string = in.readLine()) != null) {
     System.out.println(string);
   }
   in.close();
 }
 public static void main(String[] args) throws Exception {
   if (args.length != 1) {
     System.err.println("usage: java TextReader " + "file location");
     System.exit(0);
   }
   readFile(args[0]);
 }

}

 </source>
   
  
 
  

Simplify the code in TextReader by using java.util.Scanner

   <source lang="java">

import java.io.File; import java.util.Scanner; public class Main {

 static void readFile(String fileName) throws Exception {
   File file = new File(fileName);
   Scanner scanner = new Scanner(file);
   while (scanner.hasNext()) {
     System.out.println(scanner.next());
   }
   scanner.close();
 }
 public static void main(String[] args) throws Exception{
   if (args.length != 1) {
     System.err.println("usage: java TextScanner1" + "file location");
     System.exit(0);
   }
   readFile(args[0]);
 }

}

 </source>
   
  
 
  

Split a string using Scanner class

   <source lang="java">

import java.io.File; import java.util.Scanner; public class Main {

 public static void main(String[] args) throws Exception {
   File file = new File("data.txt");
   Scanner scanner = new Scanner(file);
   while (scanner.hasNextLine()) {
     String line = scanner.nextLine();
     Scanner lineScanner = new Scanner(line);
     lineScanner.useDelimiter(",");
     while (lineScanner.hasNext()) {
       String part = lineScanner.next();
       System.out.print(part + ", ");
     }
     System.out.println();
   }
 }

}

 </source>