queryisbnservlet.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.beans.Book;
import cn.edu.jmu.beans.Title;
import cn.edu.jmu.util.MysqlUtil;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.commons.dbutils.handlers.BeanListHandler;

/**
 *
 * @author jiangchen
 */
public class queryISBNServlet 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("adminIndex.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 isbn = (String) request.getParameter("isbn");
        if (isbn.equals("")) {
            message = "对不起，ISBN不能为空，请您重新输入！";
            state = 2;
        } else {
            String[] param1 = {isbn};
            String sql = "select * from title where isbn=?";
            MysqlUtil db = new MysqlUtil("java:/comp/env/jdbc/mysql");
            db.init();
            List result1 = (List) db.query(sql, param1, new BeanListHandler(Title.class));
            if (result1.isEmpty()) {
                message = "该图书信息不存在，请确认ISBN是否正确？如正确，是否添加图书信息？";
                state = 1;
                request.setAttribute("isbn", isbn);
            } else {
                Title title = (Title) result1.get(0);
                request.setAttribute("title", title);
                String tid = title.getTid();
                String[] param2 = {tid};
                sql = "select * from book where tid=?";
                List result2 = (List) db.query(sql, param2, new BeanListHandler(Book.class));
                request.setAttribute("result", result2);
            }
        }
        if (state == 2) {
            String hyperlink = "<a href=\"bookManage.jsp\">返回</a>";
            request.setAttribute("title", "操作失败！");
            request.setAttribute("message", message);
            request.setAttribute("hyperlink", hyperlink);
            request.getRequestDispatcher("/result.jsp").forward(request, response);
        } else if (state == 1) {
            request.setAttribute("message", message);
            request.getRequestDispatcher("/isAddTitle.jsp").forward(request, response);
        } else {
            request.getRequestDispatcher("/modifyTitle.jsp").forward(request, response);
        }
    }

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