messageservlet.java

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package servlet;

import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import myTools.DataBase;
import java.sql.*;
import myTools.TimeMaker;

/**
 *
 * @author Administrator
 */
public class MessageServlet extends HttpServlet {
   
    /** 
    * Processes requests for both HTTP <code>GET</code> and <code>POST</code> methods.
    * @param request servlet request
    * @param response servlet response
    */
    protected void processRequest(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        String operation = (String) request.getParameter("operation");
        System.out.println(operation);
        DataBase db = new DataBase();
        ResultSet rs = null;
        db.connectToDB();
        try {
            if(operation == null){
                System.out.println("The Message Control Is Wrong");
            }else if(operation.equals("add")){
                String host_id = request.getParameter("host_id");
                String visitor_id = request.getParameter("visitor_id");
                if(host_id.equals(visitor_id)){
                    response.sendRedirect("error.jsp?error_id=1");
                }else{
                    String message_content = new String(request.getParameter("message").getBytes("ISO-8859-1"),"gb2312");
                    String time = TimeMaker.getTime();
                    db.executeUpdate("insert into messages (host_id, visitor_id, message_content, message_date) values ('" + visitor_id + "', '" + host_id + "', '" + message_content + "', '" + time + "')");
                    response.sendRedirect("messages.jsp");
                }
            }else if(operation.equals("delete")){
                String user_id = (String)request.getSession().getAttribute("user_id");
                String be_visited_id = (String)request.getSession().getAttribute("be_visited_id");
                if(user_id.equals(request)){
                    String message_id = (String)request.getParameter("message_id");
                    db.executeUpdate("delete from messages where message_id = " + message_id);
                    response.sendRedirect("messages.jsp");
                }else{
                    response.sendRedirect("error.jsp?error_id=3");
                }
            }else if(operation.equals("response")){
                String visitor_id = request.getParameter("visitor_id");
                String message_id = request.getParameter("message_id");
                String message_content = new String(request.getParameter("message").getBytes("ISO-8859-1"),"gb2312");
                String sql = "select host_id, visitor_id from messages where message_id = " + message_id;
                rs = db.executeQuery(sql);
                String h = "";
                String v = "";
                try{
                    if(rs.next()){
                        h = rs.getString(1);
                        v = rs.getString(2);
                        String time = TimeMaker.getTime();
                        String sql1 = "insert into messages (host_id, visitor_id, message_content, message_date) values ('" + h + "', '" + visitor_id + "', '" + message_content + "', '" + time + "')";
                        String sql2 = "insert into messages (host_id, visitor_id, message_content, message_date) values ('" + v + "', '" + visitor_id + "', '" + message_content + "', '" + time + "')";
                        db.executeUpdate(sql1);
                        db.executeUpdate(sql2);
                        response.sendRedirect("messages.jsp");
                    }
                }catch(Exception eee){
                    
                }
            }
        }finally { 
            db.close();
        }
    } 

    // <editor-fold defaultstate="collapsed" desc="HttpServlet 方法。单击左侧的 + 号以编辑代码。">
    /** 
    * Handles the HTTP <code>GET</code> method.
    * @param request servlet request
    * @param response servlet response
    */
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        processRequest(request, response);
    } 

    /** 
    * Handles the HTTP <code>POST</code> method.
    * @param request servlet request
    * @param response servlet response
    */
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        processRequest(request, response);
    }
}