How to Convert Java Properties to HashMap

How to Convert Java Properties to HashMap

Java Properties and HashMaps are both popular Java data structures that allow you to store key/value pairs. While Properties is primarily used for reading from and writing to configuration files, a HashMap is a more general data structure that can be used for a variety of purposes. Fortunately, converting one to the other is relatively easy.

Step 1: Create a Properties Object

The first step is to create a Properties object. This can be done by instantiating it directly, or by loading a properties file into it. For example:

Properties props = new Properties();
props.load(new FileReader("myconfig.properties"));

Step 2: Create an Empty HashMap

The next step is to create an empty HashMap that will be used to store the converted values. This can be done by instantiating a new HashMap object, for example:

Map<String, String> map = new HashMap<String, String>();

Step 3: Iterate Through the Properties

Once you have both your Properties object and HashMap ready, you can iterate through the entries in the Properties and add them to the HashMap. This can be done using the Properties object's entrySet() method, as follows:

for (Map.Entry<Object, Object> entry : props.entrySet()) {
  map.put((String) entry.getKey(), (String) entry.getValue());
}

The above loop will iterate through all the key/value pairs in the Properties object and add them to the HashMap. The keys and values will be type-casted to Strings before being added to the HashMap.

Conclusion

By following the steps outlined above, you can easily convert a Java Properties object to a HashMap. This can be particularly useful if you need to access the contents of a configuration file in a different way than what a Properties object typically allows for.