Getting started with MVC(5)

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java mvc 8 ee

Handle PUT and DELETE request
When you try to submit aPUTorDELETEhttp request via form submission, and you want to invoke the methods annotated with@PUTor@DELETEin the Controller to handle the request.
Unfortunately it does not work.
There is a simple solution which can help us to overcome this issue.
If you have used Spring MVC before and I think you could know there is aHiddenMethodFilterin the Spirng MVC to fix this issue. Java EE 8 MVC does not ship the similar Filter, we can create one.
Solution

Create a Filter to convert the request method to the target HTTP method.

@WebFilter(filterName = "HiddenHttpMethodFilter", urlPatterns = {"/*"}, dispatcherTypes = {DispatcherType.REQUEST})
public class HiddenHttpMethodFilter implements Filter {

    @Inject
    Logger log;

    /**
    * Default method parameter: {@code _method}
    */
    public static final String DEFAULT_METHOD_PARAM = "_method";

    private String methodParam = DEFAULT_METHOD_PARAM;

    /**
    * Set the parameter name to look for HTTP methods.
    *
    * @see #DEFAULT_METHOD_PARAM
    */
    public void setMethodParam(String methodParam) {
        this.methodParam = methodParam;
    }

    @Override
    public void doFilter(ServletRequest req, ServletResponse res, FilterChain filterChain)
            throws ServletException, IOException {
        log.log(Level.INFO, "entering HttpHiddenFilter...");
        HttpServletRequest request = (HttpServletRequest) req;
        HttpServletResponse response = (HttpServletResponse) res;

        String paramValue = request.getParameter(this.methodParam);
        log.log(Level.INFO, "paramValue @" + paramValue);
        log.log(Level.INFO, "request method @" + request.getMethod());

        if ("POST".equals(request.getMethod()) && paramValue != null && paramValue.trim().length() > 0) {
            String method = paramValue.toUpperCase(Locale.ENGLISH);
            HttpServletRequest wrapper = new HttpMethodRequestWrapper(request, method);
            filterChain.doFilter(wrapper, response);
        } else {
            filterChain.doFilter(request, response);
        }
    }

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {

    }

    @Override
    public void destroy() {

    }

    /**
    * Simple {@link HttpServletRequest} wrapper that returns the supplied
    * method for {@link HttpServletRequest#getMethod()}.
    */
    private static class HttpMethodRequestWrapper extends HttpServletRequestWrapper {

        private final String method;

        public HttpMethodRequestWrapper(HttpServletRequest request, String method) {
            super(request);
            this.method = method;
        }

        @Override
        public String getMethod() {
            return this.method;
        }
    }

}

Add a hidden field named_methodin the form, which value is the target HTTP method.

<form action="${markDoingUrl}" method="post">
    <input type="hidden" name="_method" value="PUT"><jsp:text /></input>
    <input type="hidden" name="status" value="DOING"><jsp:text /></input>
    <button type="submit" class="btn btn-sm btn-primary">
        <span class="glyphicon glyphicon-play" aria-hidden="true"><jsp:text /></span>
        START
    </button>
</form>

The@PUTmethod in theTaskController.

@PUT
@Path("{id}/status")
public Response updateStatus(@PathParam(value = "id") Long id, @NotNull @FormParam(value = "status") String status) {
    log.log(Level.INFO, "updating status of the existed task@id:{0}, status:{1}", new Object[]{id, status});

    Task task = taskRepository.findById(id);

    task.setStatus(Task.Status.valueOf(status));

    taskRepository.update(task);

    flashMessage.notify(Type.info, "Task status was updated successfully!");

    return Response.ok("redirect:tasks").build();
}

Source codes

Clone the codes from my github.com account. https://github.com/hantsy/ee8-sandbox/

Open the mvc project in NetBeans IDE.

Run it on Glassfish.

After it is deployed and runging on Glassfish application server, navigate http://localhost:8080/ee8-mvc/mvc/tasks in browser.

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