login.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 com.db.DBAccess;

public class Login
    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();
    //获得用户名和密码
    String name = request.getParameter("username");
    String password = request.getParameter("password");
    DBAccess db = new DBAccess();
    String message = "用户名或密码错误,请重试!";
    HttpSession se = request.getSession();
    try {
      //如果有该用户就登陆成功，否则失败
      if (db.checkUser(name, password)) {
        request.setAttribute("mes", message);
        se.setAttribute("username", name);
        db.setState(name);
        request.getRequestDispatcher("index.jsp").forward(request, response);
        return;
      }
      else {
        request.setAttribute("mes", message);
        request.getRequestDispatcher("login.jsp").forward(request, response);
        return;
      }

    }
    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() {
  }
}