deletebookservlet.java

图书馆管理系统！利用java的mvc开发！

/*
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 * 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 deleteBookServlet 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 bid = request.getParameter("bid");
        String isbn = request.getParameter("isbn");
        String collectNumString = request.getParameter("collectNum");
        int collectNum = Integer.parseInt(collectNumString);
        collectNum = collectNum - 1;
        String sql = "delete from book where bid=?";
        String[] param1 = {bid};
        MysqlUtil db = new MysqlUtil("java:/comp/env/jdbc/mysql");
        db.init();
        db.update(sql, param1);

        sql = "update title set collectNum=? where isbn=?";
        Object[] param2 = {collectNum, isbn};
        db.update(sql, param2);

        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", "操作成功！");
        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>
}