I am using a javax.servlet.http.HttpServletRequest to implement a web application.
I have no problem to get the parameter of a request using the getParameter method. However I don't know how to set a parameter in my request.
解决方案
You can't, not using the standard API. HttpServletRequest represent a request received by the server, and so adding new parameters is not a valid option (as far as the API is concerned).
You could in principle implement a subclass of HttpServletRequestWrapper which wraps the original request, and intercepts the getParameter() methods, and pass the wrapped request on when you forward.
If you go this route, you should use a Filter to replace your HttpServletRequest with a HttpServletRequestWrapper:
public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
if (servletRequest instanceof HttpServletRequest) {
HttpServletRequest request = (HttpServletRequest) servletRequest;
// Check wether the current request needs to be able to support the body to be read multiple times
if (MULTI_READ_HTTP_METHODS.contains(request.getMethod())) {
// Override current HttpServletRequest with custom implementation
filterChain.doFilter(new HttpServletRequestWrapper(request), servletResponse);
return;
}
}
filterChain.doFilter(servletRequest, servletResponse);
}