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How do I get Spring's Bean from a servlet?

Category: javax.servlet, viewed: 15035 time(s).

I've created a servlet based web application and I want to used Spring beans in it. So how do I do this in my servlet. Well it simple enough to do this. First of all of course I have to obtain the Spring's WebApplicationContext, from where I can grab the required bean by my servlet.

Let's see some lines of code on how to do it, here we go:

protected void doGet(HttpServletRequest request,
                     HttpServletResponse response)
        throws ServletException, IOException {

    ServletContext context = getServletContext();
    WebApplicationContext applicationContext =
            WebApplicationContextUtils
            .getWebApplicationContext(context);

    Long userId = Long.valueOf(request.getParameter("user_id"));
    UserDao dao = (UserDao) applicationContext.getBean("userDao");
    User user = dao.getUser(userId);

    response.setContentType("text/html");
    PrintWriter pw = response.getWriter();
    pw.print("User Details: " + user.toString());
    pw.flush();
}

Inside the Java Servlet doGet() method above I get the ServletContext, next the WebApplicationContextUtils help me to get Spring WebApplicationContext. With this object in my hand I can get my UserDao implementation and do a query from database.