Problem - How you can read primitive data types from a file ?

Contents

1. 1 Program :
   1. 1.1 Step 1 - Coding
   2. 1.2 Step 2 - Deployment
   3. 1.3 Step 3 - Testing
   4. 1.4 Output

Solution : java.io.DataInputStream  is use to converts  bytes into primitive data types. java.io.DataInputStream is connect with java.io.FileInputStream to get bytes from a file.

Prerequisite:-  Primitive data has been written to a file with help of previous program.

Program :

Step 1 - Coding

Create a text file c:/sunilos/ReadPrimitiveData.java and copy below contents.

import java.io.DataInputStream;
import java.io.FileInputStream;

/**
 * A program to read primitive data types.
 */  

public class ReadPrimitiveData {

    public static void main(String[] args) throws Exception{

        FileInputStream file = new FileInputStream("c:/sunilos/sunilos.dat");
       
        DataInputStream in = new DataInputStream(file);
       
        System.out.println(in.readInt());
        System.out.println(in.readBoolean());
        System.out.println(in.readChar());
        System.out.println(in.readDouble());
        in.close();
       
    }

}

Step 2 - Deployment

1. Create a folder 'c:\sunilos'. 
2. Create or copy ReadPrimitiveData.java into 'c:\sunilos' folder.
3. Open your command prompt and go to  'c:\sunilos'
   
4. Compile ReadPrimitiveData.java with help of 
• javac ReadPrimitiveData.java command. Command will create ReadPrimitiveData.class file in the same folder.
  
5. Congratulations!! your Java program is ready to serve.

Step 3 - Testing

1. Make sure you are on Command Prompt under c:\sunilos directory
   
2. Now start your java program from command prompt with help of 
• java ReadPrimitiveData command.

Output

1
true
A
1.2

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