URL Special Signs

For example, a URL that includes a query string parameter for a search term might look like this:

https://www.example.com/search?term=best+restaurants

In this URL, the plus sign is used to represent the space between "best" and "restaurants" in the search term "best restaurants". When the web server receives this request, it would interpret the plus sign as a space and perform the search accordingly.

If you need to include a plus sign (+) as a literal character in a URL, you can use URL encoding to represent it as %2B.

URL encoding is a process in which special characters are replaced with their corresponding hexadecimal ASCII codes. This allows them to be transmitted over the internet without interfering with the meaning of the URL.

So if you want to include a plus sign in a URL, you can replace it with %2B. For example, the following URL includes a literal plus sign in the parameter value:

https://www.example.com/search?query=2+2=4%2B2

In this case, the plus sign between "4" and "2" is represented by %2B, which is the URL-encoded value of the plus sign character. When the web server receives this request, it would interpret the %2B code as a plus sign and perform the search accordingly.

Good Practice of Creating URI from String

It is generally recommended to use the java.net.URI class to create and manipulate URIs rather than constructing URIs directly from strings. This is because the URI class provides a higher level of abstraction and ensures that the resulting URI is valid and conforms to the URI syntax rules.The URI class provides constructors and methods to create and manipulate URIs, and it automatically handles any encoding and decoding that needs to be done. For example, if you want to create a URI from a string that contains special characters, you can use the URI(String) constructor as follows:

URI uri = new URI("http", "example.com", "/path with spaces", "query=string", "fragment");

This will create a URI with the following components:

http://example.com/path%20with%20spaces?query=string#fragment

Note that the path component, which contains spaces, is automatically encoded as %20.When creating a URI from user input, it is important to validate the input and ensure that it does not contain any invalid characters or sequences. This can be done using the java.net.URI.create(String) method, which will throw an IllegalArgumentException if the input string is not a valid URI.Overall, using the URI class provides a more robust and reliable way to create and manipulate URIs in Java.