updatebookservlet.java

图书馆管理系统！利用java的mvc开发！

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
package cn.edu.jmu.jc;

import cn.edu.jmu.util.MysqlUtil;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 *
 * @author jiangchen
 */
public class updateBookServlet 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 {
        response.setContentType("text/html;charset=utf-8");
        request.setCharacterEncoding("utf-8");
    }

    // <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);
        if (request.getHeader("referer") == null) {
            response.sendRedirect("index.jsp");
        } else {
            doPost(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);
        String message = "";
        int state = 0;
        String layPlace = request.getParameter("layPlace");
        String bid = request.getParameter("bid");
        String isbn = request.getParameter("isbn");
        if (layPlace.equals("")) {
            message = "对不起，藏书地点不能为空，请您重新输入！";
            state = 1;
        } else {
            String[] param = {layPlace, bid};
            String sql = "update book set layPlace=? where bid=?";
            MysqlUtil db = new MysqlUtil("java:/comp/env/jdbc/mysql");
            db.init();
            db.update(sql, param);
            message = "操作成功！";
        }

        if (state == 0) {
            String hyperlink = "<form method=\"post\" action=\"/libraryMIS/queryISBN\">" +
                    "<table align=\"center\"><input type=\"submit\" value=\"返回\"/>" +
                    "<input type=\"hidden\" name=\"isbn\" value=\"" + isbn +
                    "\"/></table></form>";
            request.setAttribute("title", "操作成功！");
            request.setAttribute("message", message);
            request.setAttribute("hyperlink", hyperlink);
            request.getRequestDispatcher("/result.jsp").forward(request, response);
        } else {
            String hyperlink = "<input type=button value=\"返回\" onClick=\"history.back(-1)\">";
            request.setAttribute("title", "操作失败！");
            request.setAttribute("message", message);
            request.setAttribute("hyperlink", hyperlink);
            request.getRequestDispatcher("/result.jsp").forward(request, response);
        }
    }

    /** 
     * Returns a short description of the servlet.
     */
    public String getServletInfo() {
        return "Short description";
    }// </editor-fold>
}