Servlets run on a server and return html and/or graphic code to a web browser in response to a request from the browser.
The simple servlet (dbcservXX.java) accepts data from a browser either through the POST method (as when a submit button is pressed on a browser-displayed form and the browser POSTs the forms parameters back to the server), or through the GET method - when a URL linked from the browser page contains additional parameters, such as
<IMG src=http://localhost/servlet/dbcserv128?CODETYPE=0&DATA=12345678>
In this case the servlet returns a image – a Portable Network Graphic (PNG) image using the code in the sample servlet.
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