ajaxhandlerservlet.java

关于Ajax的

package allan.ajax.action;

import java.io.IOException;
import java.io.PrintWriter;
import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.Map;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import allan.ajax.entity.User;
import allan.ajax.service.UserService;

public class AjaxHandlerServlet extends HttpServlet {

    public void execute(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String path = request.getServletPath();
        path = path.substring(0, path.lastIndexOf("."));
        String handler = getHandlerMapping().get(path);
        if (handler == null) {
            response.sendError(HttpServletResponse.SC_NOT_FOUND, "Unknown path:" + path);
            return;
        }

        try {
            response.setHeader("Cache-Control", "no-cache");
            Class[] parameterTypes = new Class[] { HttpServletRequest.class, HttpServletResponse.class };
            Method method = this.getClass().getDeclaredMethod(handler, parameterTypes);
            method.invoke(this, request, response);
        } catch (Exception e) {
            e.printStackTrace();
            throw new ServletException(e);
        }
    }

    protected Map<String, String> getHandlerMapping() {
        Map<String, String> handlers = new HashMap<String, String>();
        handlers.put("/user/validateUserName", "validateUserName");
        handlers.put("/user/add", "addUser");
        handlers.put("/request/get", "handleGetParameters");
        handlers.put("/request/post", "handlePostParameters");
        return handlers;
    }

    protected void handleGetParameters(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        response.setContentType("text/html;charset=gbk");
        PrintWriter out = response.getWriter();

        String name = request.getParameter("name");
        String gender = request.getParameter("gender");
        String greetings = "尊敬的" + name;
        if (gender.equals("m")) {
            greetings += "先生";
        } else {
            greetings += "女士";
        }
        out.print(greetings);
        out.print(",您好!");

        out.close();
    }

    protected void handlePostParameters(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        response.setContentType("text/html;charset=gbk");
        PrintWriter out = response.getWriter();

        request.setCharacterEncoding("utf-8");
        String name = request.getParameter("name");
        String gender = request.getParameter("gender");
        String greetings = "尊敬的" + name;
        if (gender.equals("m")) {
            greetings += "先生";
        } else {
            greetings += "女士";
        }
        out.print(greetings);
        out.print(",您好!");

        out.close();
    }

    protected void validateUserName(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        response.setContentType("text/plain");
        PrintWriter out = response.getWriter();

        String userName = request.getParameter("userName");

        UserService userService = new UserService();
        boolean exist = false;
        try {
            exist = userService.isUserNameInUser(userName);
        } catch (Exception e) {
            e.printStackTrace();
            throw new ServletException(e);
        }

        if (exist) {
            out.print("inuse");
        } else {
            out.print("good name");
        }
        out.close();
    }

    protected void addUser(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        User user = createUserFromRequest(request);
        UserService userService = new UserService();
        try {
            userService.add(user);
        } catch (Exception e) {
            e.printStackTrace();
            throw new ServletException(e);
        }
    }

    protected User createUserFromRequest(HttpServletRequest request) {
        String userName = request.getParameter("userName");
        String password = request.getParameter("password");
        String email = request.getParameter("email");
        User user = new User();
        user.setUserName(userName);
        user.setPassword(password);
        user.setEmail(email);
        return user;
    }

    public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        execute(request, response);
    }

    public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        execute(request, response);
    }

}