checkuser.java

功能描述 1） 后台：管理员负责对整个论坛进行管理

package bbs.servlet;

import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.util.*;
import bbs.db.UserDBAccess;

public class CheckUser
    extends HttpServlet {
  private static final String CONTENT_TYPE = "text/html; charset=GBK";

  //Initialize global variables
  public void init() throws ServletException {
  }

  //Process the HTTP Get request
  public void doGet(HttpServletRequest request, HttpServletResponse response) throws
      ServletException, IOException {
    response.setContentType(CONTENT_TYPE);
    PrintWriter out = response.getWriter();
    //获得用户名
    String username = request.getParameter("username");
    try{
      UserDBAccess db = new UserDBAccess();
      //判断用户名是否存在
      if(db.checkUser(username)){
        request.setAttribute("mm","对不起,该用户名已被注册了!");
      }
      else{
        request.setAttribute("mm","恭喜,该用户名未被注册!");
        request.setAttribute("uname",username);
      }
      request.getRequestDispatcher("register.jsp").forward(request,response);
    }
    catch(Exception ex){
      ex.printStackTrace();
      request.setAttribute("message", ex.toString());
      request.getRequestDispatcher("error.jsp").forward(request, response);
    }
    out.close();
  }

  //Process the HTTP Post request
  public void doPost(HttpServletRequest request, HttpServletResponse response) throws
      ServletException, IOException {
    doGet(request, response);
  }

  //Clean up resources
  public void destroy() {
  }
}