doGet

DoGet is a method in the Java Servlet API used to handle HTTP GET requests. It is defined in the HttpServlet class and is commonly overridden by developers who extend HttpServlet. The standard method signature is protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException. The servlet container calls doGet when a client issues a GET request that maps to the servlet, as configured by a URL pattern in web.xml or by the @WebServlet annotation. If a servlet does not override doGet, the default HttpServlet implementation responds with an HTTP 405 Method Not Allowed.

In a typical doGet implementation, the code reads request data, such as query parameters, via methods like req.getParameter, and writes a response through resp.getWriter() or resp.getOutputStream(). Developers usually set the response content type with resp.setContentType and may forward to a view (for example, a JSP) using a RequestDispatcher or redirect the client with resp.sendRedirect. GET responses commonly deliver data in text, HTML, JSON, or XML formats and may be cached or bookmarked.

DoGet is intended for safe, idempotent operations that do not modify server state. If an action changes data or has side effects, doPost or another HTTP method should be used. Servlet mappings determine which URL patterns invoke doGet, and these mappings can be defined in web.xml or via annotations such as @WebServlet.

Thread safety is an important consideration: a single servlet instance handles many requests concurrently, so doGet should avoid using mutable instance fields, and should rely on local variables or properly synchronized resources. Proper error handling, resource management, and adherence to HTTP semantics help ensure robust doGet implementations.