我正在使用此处找到的设计模式。它有一个 FrontController、Command -> Service 和 Dao。
如果我在浏览器中加载此 URL(viewprofile 是 jsp 的名称):
http://localhost:8080/MyApplication/FrontController/viewprofile
我不知道如何自动调用ViewProfileCommand
然后显示用户的详细信息。
目前我拥有它的方式是这样的,为了调用ViewProfileCommand
我必须将它连接到 URL 上,例如:http://localhost:8080/MyApplication/FrontController/viewprofile?action=ViewProfile
。
如何将 jsp 映射到命令而不必将其连接到 URL?谢谢
前端控制器:
package com.secret.bookstore.servlet;
import java.io.IOException;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.secret.bookstore.command.Command;
import com.secret.bookstore.command.CommandFactory;
import com.secret.bookstore.exceptions.CommandCreationException;
import com.sun.net.httpserver.Filter.Chain;
/*
* Front Controller (Mediator Pattern)
*/
@WebServlet(urlPatterns={"/FrontController"})
public class FrontController extends HttpServlet {
/**
*
*/
private static final long serialVersionUID = 1L;
public FrontController(){
super();
}
protected void service(HttpServletRequest request, HttpServletResponse response){
String action = request.getParameter("action");
CommandFactory commandFactory = CommandFactory.getInstance();
Command command = null;
String view = null;
view = request.getPathInfo().substring(1);
if(action != null){
try {
command = commandFactory.createCommand(action);
view = command.execute(request, response);
} catch(CommandCreationException e) {
e.printStackTrace();
}
}
forwardToPage(request, response, view);
}
/**
* Forward to server to the supplied page
*/
private void forwardToPage(HttpServletRequest request, HttpServletResponse response, String view){
//Get the request dispatcher object and forward the request to the appropriate JSP page...
if(view.equals(request.getPathInfo().substring(1))){
RequestDispatcher dispatcher = request.getRequestDispatcher("/WEB-INF/" + view + ".jsp");
try {
dispatcher.forward(request, response);
} catch (ServletException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
} else {
try {
response.sendRedirect(view);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}