An exception occurred processing JSP page /view/book/book_edit.jsp at line 21

<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<%@ page language="java" import="java.util.*" pageEncoding="gbk"%>
<%@ page language="java" import="booksystem.entity.*"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<jsp:useBean id="alBooks" class="booksystem.logic.Book"></jsp:useBean>
<html>
<head>
<meta charset="gbk">
<title></title>
<link rel="stylesheet" href="../../css/reset.css" />
<link rel="stylesheet" href="../../css/register.css" />
</head>

<%
  String bookCode=request.getParameter("bookCode");
  String sqlTxt="select*from bookinfo where bookCode='"+bookCode+"'";
  ArrayList<BookInfo> al = alBooks.getBook_List_User(sqlTxt);
  BookInfo bookInfo = al.get(0);
  %>

<body>
<div class="page">
<div class="bookwarrp">
<div class="book">修改图书</div>
        <div class="book_form">
<form id="book_add" name="book_add" method="get" onsubmit="" action="servlet/EditBook"> 图书序号：
<input type="text" id="bookCode" name="bookCode"value=<%=bookInfo.getBookCode() %>><br><br> 图书名称：
<input type="text" id="BookName" name="BookName" value=<%=bookInfo.getBookName() %>><br><br>
<span>作者：</span>
<input type="text" id="author" name="author" value=<%=bookInfo.getAuthor() %>><br><br> <span>出版社：</span>
<input type="text" id="cbs" name="cbs" value=<%=bookInfo.getCbs() %>><br><br> <span>状态：</span>
<input type="text" id="Bookstatues" name="Bookstatues" value=<%=bookInfo.getBookstatues() %>><br><br>
<span>索书号：</span>
<input type="text" id="booktpip" name="booktpip" value=<%=bookInfo.getBooktpip() %>><br><br>
<span>馆藏地：</span>
<input type="text" id="position" name="position" value=<%=bookInfo.getPosition() %>><br><br>
<span>内容简介：</span>
<input type="text" id="content" name="content" value=<%=bookInfo.getContent() %>><br><br>
<span>类别：</span>
<input type="text" id="lb" name="lb" value=<%=bookInfo.getLb() %>><br><br>

<span>书的封面：</span>
<input type="text" id="bookimage" name="bookimage" value=<%=bookInfo.getBookimage() %>><br><br>
                    <input type="submit" name="submit" value="提交(修改)"/>           </form>
</div>
</div>
</div>
</body>
</html>
运行报错严重: Servlet.service() for servlet [jsp] in context with path [/javaee] threw exception [An exception occurred processing JSP page /view/book/book_edit.jsp at line 2118:   String bookCode=request.getParameter("bookCode");
19:   String sqlTxt="select*from bookinfo where bookCode='"+bookCode+"'";
20:   ArrayList<BookInfo> al = alBooks.getBook_List_User(sqlTxt);
21:   BookInfo bookInfo = al.get(0);
22:   %>
23: 
24:  <body>
Stacktrace:] with root cause
java.lang.IndexOutOfBoundsException: Index: 0, Size: 0
at java.util.ArrayList.rangeCheck(ArrayList.java:653)
at java.util.ArrayList.get(ArrayList.java:429)
at org.apache.jsp.view.book.book_005fedit_jsp._jspService(book_005fedit_jsp.java:93)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:432)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:395)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:339)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:503)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:170)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:421)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1070)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:611)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:316)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:745)