CODEWITHSUNDEEP
javaproperties
thestiggg
thestiggg

Reputation: 33

Java Properties File appending new values

I have an application that implements a JTree and populates the tree with a java properties file as default; The nodes are the keys and the values are the contents of the node. The application was designed to be dynamic so a JButton and JTextField are implemented to take in new values and put the values in the exists keys in the properties file.

So for example I have the line below as a default value in a sample.properties file

node=cat,dog,mice

and using the JTextField and JButton I input "rabbit" to append to the node, to look like:

node=cat,dog,mice,rabbit

I've implemented JTextField and JButton and have them working but I just can't seem to find a good way to append new values to existing keys in the properties file.

Upvotes: 3

Views: 10010

Answers (2)

user3229382
user3229382

Reputation: 81

I would look at Apache Commons Configuration. It has very specific examples that do what you are asking.

Try:

import org.apache.commons.configuration.PropertiesConfiguration;

PropertiesConfiguration config = new PropertiesConfiguration(
    "config.properties");

config.setProperty("my.property", somevalue);

config.save();

Upvotes: 1

Zaw Than oo
Zaw Than oo

Reputation: 9935

Just FileWriter

FileWriter fileWritter = new FileWriter("example.properties", true);
BufferedWriter bufferWritter = new BufferedWriter(fileWritter);
bufferWritter.append("PROPERTES_YOUR_KEY=PROPERTES_YOUR_VALUE");
bufferWritter.close();

Update

Properties API does not support, I am not sure why you need this functionality.
You can try as below :

example.properties

PROPERTIES_KEY_3=PROPERTIES_VALUE_3
PROPERTIES_KEY_2=PROPERTIES_VALUE_2
PROPERTIES_KEY_1=PROPERTIES_VALUE_1

Program

Properties pop = new Properties();
pop.load(new FileInputStream("example.properties"));
pop.put("PROPERTIES_KEY_3", "OVERWRITE_VALUE");
FileOutputStream output = new FileOutputStream("example.properties");
pop.store(output, "This is overwrite file");

output

PROPERTIES_KEY_3=OVERWRITE_VALUE
PROPERTIES_KEY_2=PROPERTIES_VALUE_2
PROPERTIES_KEY_1=PROPERTIES_VALUE_1

Upvotes: 3

Related Questions