I wanted to know if you can explain or pass a video or page that explains how to create a web service with java where I have to pass a string and given that string go to the bd to find a record and return the data of that record in json format. I've been searching but I did not find much, I'm new with this web services. Thanks !!
Hello according to your question what you are looking for is guidance about web services in Java using RESTFUL, there are many Frameworks that make what you say possible, however it is necessary to know the bases, I recommend using Spring, a very good framework and that does what you need.
In the following link is a tutorial on how to obtain a JSON from a request, assuming you know the language of JAVA, once you make the example you can create your own web service using your database.