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Write the Keys and Values of the Properties files in Java


In this section, you will learn how to add the keys and it's values of the properties files in Java. You know the properties files have the the keys and values of the properties files. But this time you will learn, how to insert the keys and values in the properties files. The properties file continuously update the day, date, times and GMT time and years according to your setting the current date and time of the system. This example solves your problems.

This program takes a file name and it checks, if the file exists then performs the next operations Otherwise, it shows the appropriate messages like: "File not found!" and "Enter file name which has properties extension :". This message shows until, when you could not enter the correct file name. If the file name is correct then it takes the key and key-values of the properties file. After that it shows the appropriate message like: "Operation completly successfuly!". Then, you will see in the properties file, your inserted keys and values had been inserted in the properties file. 

Here, the following methods and APIs interfaces had been used in the program:

pro.setProperty(String key, String val):
This method used to insert the keys and values in the properties file. This method calls the hash table of the Properties class and put it in the properties files. It takes the two values of the string types like: key and val. The key that means takes the keys name and val means it takes the value of the key of the properties files. Both values to be insert in the properties files.

pro.store((OutputStream out),null):
This is the method that can be used to write or store the keys and values in properties files with no any descriptions. The OutputStream used to when you use the load() method in the program. It takes the OutputStream and comments, but here the only used to OutputStream and no any header or comments( as like descriptions of the properties list).

Here is the code of program:

import java.io.*;
import java.util.*;

public class WriteProperty{
  String str, key, val;
  public static void main(String[] args) {
    WriteProperty w = new WriteProperty();
  public WriteProperty(){
            int check=0;
            while(check == 0){
        BufferedReader bf = new BufferedReader(new InputStreamReader(System.in));
        System.out.println("Enter file name which has properties extension:");
        str = bf.readLine();
        Properties pro = new Properties();
        File f = new File(str + ".properties");
          System.out.println("File not found!");
          FileInputStream in = new FileInputStream(f);
          System.out.print("Enter Key : ");
          key = bf.readLine();
          System.out.print("Enter Value : ");
          val = bf.readLine();
          pro.setProperty(key, val);
          pro.store(new FileOutputStream(str + ".properties"),null);
          System.out.println("Operation completly successfuly!");
    catch(IOException e){

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