错误代码

Caused by: org.apache.jasper.JasperException: 在 [86] 行处理 [/pages/manager/book_manager.jsp] 时发生异常

83: 
84: 			<%-- 椤电爜杈撳嚭鐨勫紑濮? --%>
85: 				<%-- 鎯呭喌1锛氬鏋滄?婚〉鐮佸皬浜庣瓑浜?5鐨勬儏鍐碉紝椤电爜鐨勮寖鍥存槸锛?1-鎬婚〉鐮? --%>
86: 				<c:when test="${requestScope.page.pageTotal <= 5}">
87: 
88: 					<c:forEach begin="1" end="${requestScope.page.pageTotal}" var="i">
89: 						<c:if test="${i == requestScope.page.pageNo}">


Stacktrace:
	at org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:599)
	at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:478)
	at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:380)
	at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:328)
	at jakarta.servlet.http.HttpServlet.service(HttpServlet.java:814)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:223)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:158)
	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:185)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:158)
	at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:691)
	at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:441)
	at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:367)
	at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:295)
	at top.qaqaq.web.BookServlet.page(BookServlet.java:40)
	... 30 more
Caused by: jakarta.servlet.ServletException: jakarta.servlet.jsp.JspTagException: Illegal use of &lt;when&gt;-style tag without &lt;choose&gt; as its direct parent
	at org.apache.jasper.runtime.PageContextImpl.handlePageException(PageContextImpl.java:668)
	at org.apache.jsp.pages.manager.book_005fmanager_jsp._jspService(book_005fmanager_jsp.java:433)

原因

    <c:choose> <c:when> <c:otherwise>标签
        作用：多路判断。跟 switch ... case .... default 非常接近
 
        choose 标签开始选择判断
        when 标签表示每一种判断情况
            test 属性表示当前这种判断情况的值
        otherwise 标签表示剩下的情况
 
        <c:choose> <c:when> <c:otherwise>标签使用时需要注意的点：
        1、标签里不能使用 html 注释，要使用 jsp 注释
        2、when 标签的父标签一定要是 choose 标签

多路判断没有写 <c:choose> 标签 导致报错

<c:choose>

内部代码

</c:choose>