Using StringJoiner in Java

Introduction

In Java, the StringJoiner class provides a convenient way to join multiple strings with a specified delimiter. It is especially useful when you need to concatenate strings in a loop or when dealing with collections of strings.

Creating a StringJoiner

To create a StringJoiner object, you need to specify the delimiter and optional prefix and suffix strings. Here's an example:

 StringJoiner joiner = new StringJoiner(", ", "[", "]");

In the above example, the delimiter is set to ", ", the prefix is "[", and the suffix is "]". These values can be adjusted based on your requirements.

Adding Elements

Once you have created a StringJoiner object, you can add elements to it using the add method. Here's an example:

StringJoiner joiner1 = new StringJoiner(", ");
        joiner1.add("Apple");
        joiner1.add("Banana");
        joiner1.add("Orange");
        String result1 = joiner1.toString();
        System.out.println(result1);

The resulting string will be "Apple, Banana, Orange".

Merging StringJoiners

You can also merge multiple StringJoiner objects using the merge method. This can be useful when you want to combine separate groups of elements. Here's an example:

   StringJoiner fruitsJoiner = new StringJoiner(", ");
        fruitsJoiner.add("Apple");
        fruitsJoiner.add("Banana");

        StringJoiner colorsJoiner = new StringJoiner(", ");
        colorsJoiner.add("Red");
        colorsJoiner.add("Green");
        String res = colorsJoiner.toString();
        System.out.println(res);

        fruitsJoiner.merge(colorsJoiner);
        String result2 = fruitsJoiner.toString();
        System.out.println(result2);

The resulting string will be "Apple, Banana, Red, Green".

Handling Empty Joiners

If you have an empty StringJoiner and no elements are added to it, the resulting string will also be empty. However, you can specify a default value to handle such cases. Here's an example:

  StringJoiner joiner2 = new StringJoiner(", ", "Prefix: ", "Suffix");
        String result3 = joiner2.toString();
        System.out.println(result3);

In the above example, if no elements are added to the joiner, the resulting string will be "Prefix: Suffix".

Conclusion

The StringJoiner class provides a convenient way to concatenate strings with a specified delimiter. By using the add and merge methods, you can easily join multiple strings together, simplifying your code and improving readability. Make sure to leverage this class when working with string concatenation in Java.