Properties file in java

Properties file

1.  The properties file is a simple text file

2.  Properties file contains keys and values

3.  All the properties file are saved with the ".properties"   extension

4.  properties file is always used to store the configuration data or settings

Write Properties into properties file

package com.jsl.examples;
import java.io.FileOutputStream;
import java.util.Properties;
public class WritingProperties {

       public static void main(String[] args) {

             Properties properties=new Properties();
             FileOutputStream fos=null;
             try {
                     System.out.println("Hello");
                     fos=new FileOutputStream("connconfig.properties");
                     properties.setProperty("username", "Lakshman");
                     properties.setProperty("password", "Lakshman");
                     properties.store(fos,"User information example");
                     fos.close();

             } catch (Exception e) {
                    e.printStackTrace();
             }
       }
}

Reading properties

package com.jsl.examples;
import java.io.FileInputStream;
import java.util.Properties;
public class ReadingProperties {

   public static void main(String[] args) {
       FileInputStream fis=null;
       Properties properties=null;
       try{
              fis=new FileInputStream("connconfig.properties");
              properties=new Properties();
              properties.load(fis);
              System.out.println("User name :"+properties.getProperty("username"));
             System.out.println("Password :"+properties.getProperty("password"));
             fis.close();
       }catch (Exception e) {
              e.printStackTrace();
       }
   }
}

Spring Framework

Reading Properties file values and setting bean properties in spring framework

userinfo.properties

user.email=lakshman@gmail.com

user.password=lakshman

User.java

package com.cg.example;

public class User {
             private String email;
             private String password;
             public String getEmail() {
                    return email;
             }
             public void setEmail(String email) {
                    this.email = email;
             }
             public String getPassword() {
                    return password;
             }
             public void setPassword(String password) {
                    this.password = password;
             }
}

User.xml

             
                    user.properties
             

      

                    
                    
       

Manager.java

package com.cg.example;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class App {

       public static void main(String[] args) {
       ApplicationContext context=new ClassPathXmlApplicationContext("user.xml");
      
                    User user=(User) context.getBean("user");
                    System.out.println(user.getEmail());
                    System.out.println(user.getPassword());
            
  }
}

Output :

lakshman@gmail.com

lakshman