Kotlin Properties - Read/Write Properties from/to .properties/.XML File

In the post, we show how to Read/Write Properties from/to .Properties/.XML files by Kotlin language.

Contents

I. Kotlin – Read/Write Properties from/to .Properties file
- - 1. Write Properties to .Properties file
    - 1.1 Properties store() method
    - 1.2 Kotlin Program – write Properties to .properties file
  - 2. Read Properties from .Properties file
    - 2.1 Properties load() method
    - 2.2 Kotlin Program – Read .Properties File to Properties object
II. Kotlin – Read/Write Properties from/to .XML file
- - 1. Write Properties to .XML file
    - 1.1 Properties.storeToXML() method
    - 1.2 Kotlin Program – Write Properties object to XML file
  - 2. Read Properties from .XML file
    - 2.1 Properties.loadFromXML() method
    - 2.2 Kotlin Program – Read XML file to Properties object

I. Kotlin – Read/Write Properties from/to .Properties file

1. Write Properties to .Properties file

1.1 Properties store() method

We use java.util.Properties.store() methods:

// 1.
fun store(out: OutputStream, comments: String): Unit

-> Writes this property list (key and element pairs) in this Properties table 
to the output stream in a format suitable for loading into a Properties table using the load(InputStream) method.

// 2.
fun store(writer: Writer, comments: String): Unit

-> Writes this property list (key and element pairs) in this Properties table 
to the output character stream in a format suitable for using the load(Reader) method.

// 1.

fun store(out: OutputStream, comments: String): Unit

-> Writes this property list (key and element pairs) in this Properties table

to the output stream in a format suitable for loading into a Properties table using the load(InputStream) method.

// 2.

fun store(writer: Writer, comments: String): Unit

-> Writes this property list (key and element pairs) in this Properties table

to the output character stream in a format suitable for using the load(Reader) method.

1.2 Kotlin Program – write Properties to .properties file

package com.javasampleapproach.kotlin.properties

import java.io.FileOutputStream
import java.io.FileWriter
import java.io.IOException
import java.util.Properties

fun main(args: Array<String>) {
	val properties = Properties()

	properties.put("db.username", "username")
	properties.put("db.password", "password")
	properties.put("db.driver", "org.postgresql.Driver")
	properties.put("db.url", "jdbc:postgresql://localhost/testdb")

	var propertiesFile = System.getProperty("user.dir") + "\\file.properties"
		
	/*
	 * 	Approach 1: 
	 * 	use -> 'java.util.Properties.store(out: OutputStream, comments: String)'
	 */
	var fileOutputStream = FileOutputStream(propertiesFile)
	properties.store(fileOutputStream, "save to properties file")
	
	/*
	 * 	Approach 2: 
	 * 	use -> 'java.util.Properties.store(writer: Writer, comments: String)'
	 */
	propertiesFile = System.getProperty("user.dir") + "\\file_1.properties"
	val fileWriter = FileWriter(propertiesFile)
	properties.store(fileWriter, "save to properties file")
}

package com.javasampleapproach.kotlin.properties

import java.io.FileOutputStream

import java.io.FileWriter

import java.io.IOException

import java.util.Properties

fun main(args: Array<String>) {

val properties = Properties()

properties.put("db.username", "username")

properties.put("db.password", "password")

properties.put("db.driver", "org.postgresql.Driver")

properties.put("db.url", "jdbc:postgresql://localhost/testdb")

var propertiesFile = System.getProperty("user.dir") + "\\file.properties"

* Approach 1:

* use -> 'java.util.Properties.store(out: OutputStream, comments: String)'

var fileOutputStream = FileOutputStream(propertiesFile)

properties.store(fileOutputStream, "save to properties file")

* Approach 2:

* use -> 'java.util.Properties.store(writer: Writer, comments: String)'

propertiesFile = System.getProperty("user.dir") + "\\file_1.properties"

val fileWriter = FileWriter(propertiesFile)

properties.store(fileWriter, "save to properties file")

}

-> .properties output file:

#save to properties file
#Tue Mar 06 21:31:28 ICT 2018
db.password=password
db.url=jdbc\:postgresql\://localhost/testdb
db.username=username
db.driver=org.postgresql.Driver

#save to properties file

#Tue Mar 06 21:31:28 ICT 2018

db.password=password

db.url=jdbc\:postgresql\://localhost/testdb

db.username=username

db.driver=org.postgresql.Driver

2. Read Properties from .Properties file

2.1 Properties load() method

We use java.util.Properties.load() methods:

// 1.
fun load(inStream: InputStream): Unit
      		
-> Reads a property list (key and element pairs) from the input byte stream. 
The input stream is in a simple line-oriented format as specified in load(Reader) 
and is assumed to use the ISO 8859-1 character encoding; that is each byte is one Latin1 character.
 
// 2.
fun load(reader: Reader): Unit
          		
->	Reads a property list (key and element pairs) 
from the input character stream in a simple line-oriented format.

// 1.

fun load(inStream: InputStream): Unit

-> Reads a property list (key and element pairs) from the input byte stream.

The input stream is in a simple line-oriented format as specified in load(Reader)

and is assumed to use the ISO 8859-1 character encoding; that is each byte is one Latin1 character.

// 2.

fun load(reader: Reader): Unit

-> Reads a property list (key and element pairs)

from the input character stream in a simple line-oriented format.

2.2 Kotlin Program – Read .Properties File to Properties object

package com.javasampleapproach.kotlin.properties

import java.io.FileInputStream
import java.io.FileReader
import java.io.IOException
import java.util.Properties

fun main(args: Array<String>) {
		val properties = Properties()
		val propertiesFile = System.getProperty("user.dir") + "\\file.properties";
		
		/*
		 * 	Approach 1: 
		 * 		-> use 'java.util.Properties.load(inStream: InputStream)'
		 */
		
		val inputStream = FileInputStream(propertiesFile)
		properties.load(inputStream)
		
		properties.forEach{(k, v) -> println("key = $k, value = $v")}
		/*
			key = db.driver, value = org.postgresql.Driver
			key = db.username, value = username
			key = db.url, value = jdbc:postgresql://localhost/testdb
			key = db.password, value = password
		 */
		
		println("----------------------------");
		
		/*
		 * 	Approach 2:  
		 * 		-> use 'java.util.Properties.load(reader: Reader)'
		 */
		
		val reader = FileReader(propertiesFile)
		properties.load(reader)
		
		properties.forEach{(k, v) -> println("key = $k, value = $v")}
		/*
			key = db.driver, value = org.postgresql.Driver
			key = db.username, value = username
			key = db.url, value = jdbc:postgresql://localhost/testdb
			key = db.password, value = password
		 */
}

package com.javasampleapproach.kotlin.properties

import java.io.FileInputStream

import java.io.FileReader

import java.io.IOException

import java.util.Properties

fun main(args: Array<String>) {

val properties = Properties()

val propertiesFile = System.getProperty("user.dir") + "\\file.properties";

* Approach 1:

* -> use 'java.util.Properties.load(inStream: InputStream)'

val inputStream = FileInputStream(propertiesFile)

properties.load(inputStream)

properties.forEach{(k, v) -> println("key = $k, value = $v")}

key = db.driver, value = org.postgresql.Driver

key = db.username, value = username

key = db.url, value = jdbc:postgresql://localhost/testdb

key = db.password, value = password

println("----------------------------");

* Approach 2:

* -> use 'java.util.Properties.load(reader: Reader)'

val reader = FileReader(propertiesFile)

properties.load(reader)

properties.forEach{(k, v) -> println("key = $k, value = $v")}

key = db.driver, value = org.postgresql.Driver

key = db.username, value = username

key = db.url, value = jdbc:postgresql://localhost/testdb

key = db.password, value = password

}

II. Kotlin – Read/Write Properties from/to .XML file

1. Write Properties to .XML file

1.1 Properties.storeToXML() method

We use java.util.Properties.storeToXML() methods:

// 1.
fun storeToXML(os: OutputStream, comment: String): Unit
				
-> Emits an XML document representing all of the properties contained in this table. 
An invocation of this method of the form props.storeToXML(os, comment) 
behaves in exactly the same way as the invocation props.storeToXML(os, comment, "UTF-8");.
 
// 2.
fun storeToXML(os: OutputStream, comment: String, encoding: String): Unit

-> Emits an XML document representing all of the properties contained in this table, using the specified encoding.

// 1.

fun storeToXML(os: OutputStream, comment: String): Unit

-> Emits an XML document representing all of the properties contained in this table.

An invocation of this method of the form props.storeToXML(os, comment)

behaves in exactly the same way as the invocation props.storeToXML(os, comment, "UTF-8");.

// 2.

fun storeToXML(os: OutputStream, comment: String, encoding: String): Unit

-> Emits an XML document representing all of the properties contained in this table, using the specified encoding.

1.2 Kotlin Program – Write Properties object to XML file

package com.javasampleapproach.kotlin.properties

import java.io.FileOutputStream
import java.io.IOException
import java.nio.charset.StandardCharsets
import java.util.Properties

fun main(args: Array<String>) {
		val properties = Properties()
	
		properties.put("db.username", "username")
		properties.put("db.password", "password")
		properties.put("db.driver", "org.postgresql.Driver")
		properties.put("db.url", "jdbc:postgresql://localhost/testdb")
		
		/*
		 * 	Approach 1: 
		 * 	use -> 'java.util.Properties.storeToXML(os: OutputStream, comment: String)'
		 */
		var propertiesFile = System.getProperty("user.dir") + "\\file.xml"
		var fileOutputStream = FileOutputStream(propertiesFile)
		properties.storeToXML(fileOutputStream, "save to properties file")
		
		/*
		 * 	Approach 2: 
		 * 	use -> 'java.util.Properties.storeToXML(os: OutputStream, comment: String, encoding: String)'
		 */
		propertiesFile = System.getProperty("user.dir") + "\\file_1.xml";
		fileOutputStream = FileOutputStream(propertiesFile)
		properties.storeToXML(fileOutputStream, "save to XML file with UTF-8 enconding", StandardCharsets.UTF_8.toString());
}

package com.javasampleapproach.kotlin.properties

import java.io.FileOutputStream

import java.io.IOException

import java.nio.charset.StandardCharsets

import java.util.Properties

fun main(args: Array<String>) {

val properties = Properties()

properties.put("db.username", "username")

properties.put("db.password", "password")

properties.put("db.driver", "org.postgresql.Driver")

properties.put("db.url", "jdbc:postgresql://localhost/testdb")

* Approach 1:

* use -> 'java.util.Properties.storeToXML(os: OutputStream, comment: String)'

var propertiesFile = System.getProperty("user.dir") + "\\file.xml"

var fileOutputStream = FileOutputStream(propertiesFile)

properties.storeToXML(fileOutputStream, "save to properties file")

* Approach 2:

* use -> 'java.util.Properties.storeToXML(os: OutputStream, comment: String, encoding: String)'

propertiesFile = System.getProperty("user.dir") + "\\file_1.xml";

fileOutputStream = FileOutputStream(propertiesFile)

properties.storeToXML(fileOutputStream, "save to XML file with UTF-8 enconding", StandardCharsets.UTF_8.toString());

}

-> .xml output file:

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<!DOCTYPE properties SYSTEM "http://java.sun.com/dtd/properties.dtd">
<properties>
<comment>save to XML file with UTF-8 enconding</comment>
<entry key="db.password">password</entry>
<entry key="db.url">jdbc:postgresql://localhost/testdb</entry>
<entry key="db.username">username</entry>
<entry key="db.driver">org.postgresql.Driver</entry>
</properties>

<?xml version="1.0" encoding="UTF-8" standalone="no"?>

<!DOCTYPE properties SYSTEM "http://java.sun.com/dtd/properties.dtd">

<comment>save to XML file with UTF-8 enconding</comment>

<entry key="db.password">password</entry>

<entry key="db.url">jdbc:postgresql://localhost/testdb</entry>

<entry key="db.username">username</entry>

<entry key="db.driver">org.postgresql.Driver</entry>

</properties>

2. Read Properties from .XML file

2.1 Properties.loadFromXML() method

We use java.util.Properties.loadFromXML() method:

fun loadFromXML(in: InputStream): Unit
				 
-> Loads all of the properties represented by the XML document
on the specified input stream into this properties table.

fun loadFromXML(in: InputStream): Unit

-> Loads all of the properties represented by the XML document

on the specified input stream into this properties table.

2.2 Kotlin Program – Read XML file to Properties object

package com.javasampleapproach.kotlin.properties

import java.io.FileInputStream
import java.io.IOException
import java.util.Properties

fun main(args: Array<String>) {
	
	val properties = Properties()
	
	var propertiesFile = System.getProperty("user.dir") + "\\file.xml"
	
	/*
	 * 	use 'java.util.Properties.loadFromXML(in: InputStream)
	 */
	val inputStream = FileInputStream(propertiesFile)
	properties.loadFromXML(inputStream)
	
	properties.forEach{(k, v) -> println("key = $k, value = $v")}
	/*
		key = db.driver, value = org.postgresql.Driver
		key = db.username, value = username
		key = db.url, value = jdbc:postgresql://localhost/testdb
		key = db.password, value = password
	 */
}

package com.javasampleapproach.kotlin.properties

import java.io.FileInputStream

import java.io.IOException

import java.util.Properties

fun main(args: Array<String>) {

val properties = Properties()

var propertiesFile = System.getProperty("user.dir") + "\\file.xml"

* use 'java.util.Properties.loadFromXML(in: InputStream)

val inputStream = FileInputStream(propertiesFile)

properties.loadFromXML(inputStream)

properties.forEach{(k, v) -> println("key = $k, value = $v")}

key = db.driver, value = org.postgresql.Driver

key = db.username, value = username

key = db.url, value = jdbc:postgresql://localhost/testdb

key = db.password, value = password

}

By grokonez | March 7, 2018.

Kotlin Properties – Read/Write Properties from/to .properties/.XML File

I. Kotlin – Read/Write Properties from/to .Properties file

1. Write Properties to .Properties file

1.1 Properties store() method

1.2 Kotlin Program – write Properties to .properties file

2. Read Properties from .Properties file

2.1 Properties load() method

2.2 Kotlin Program – Read .Properties File to Properties object

II. Kotlin – Read/Write Properties from/to .XML file

1. Write Properties to .XML file

1.1 Properties.storeToXML() method

1.2 Kotlin Program – Write Properties object to XML file

2. Read Properties from .XML file

2.1 Properties.loadFromXML() method

2.2 Kotlin Program – Read XML file to Properties object

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I. Kotlin – Read/Write Properties from/to .Properties file

1. Write Properties to .Properties file

1.1 Properties store() method

1.2 Kotlin Program – write Properties to .properties file

2. Read Properties from .Properties file

2.1 Properties load() method

2.2 Kotlin Program – Read .Properties File to Properties object

II. Kotlin – Read/Write Properties from/to .XML file

1. Write Properties to .XML file

1.1 Properties.storeToXML() method

1.2 Kotlin Program – Write Properties object to XML file

2. Read Properties from .XML file

2.1 Properties.loadFromXML() method

2.2 Kotlin Program – Read XML file to Properties object

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