<table border="1" width="400px">
<tr>
<td>编号</td>
<td>标题</td>
<td>价格</td>
<td>操作</td>
</tr>
<c:forEach items="${allBook}" var="book">
<tr>
<td><c:out value="${book.id}" /></td>
<td><c:out value="${book.title}" /></td>
<td><c:out value="${book.price}" /></td>
<td>
<a href="${pageContext.request.contextPath}/manager/preUpdateBookServlet?id=${book.id}">修改</a>
<a onclick="return deleteCheck();" href="${pageContext.request.contextPath}/manager/deleteBookServlet?id=${book.id}">删除</a>
</td>
</tr>
</c:forEach>
<tr>
<td>编号</td>
<td>标题</td>
<td>价格</td>
<td>操作</td>
</tr>
<c:forEach items="${allBook}" var="book">
<tr>
<td><c:out value="${book.id}" /></td>
<td><c:out value="${book.title}" /></td>
<td><c:out value="${book.price}" /></td>
<td>
<a href="${pageContext.request.contextPath}/manager/preUpdateBookServlet?id=${book.id}">修改</a>
<a onclick="return deleteCheck();" href="${pageContext.request.contextPath}/manager/deleteBookServlet?id=${book.id}">删除</a>
</td>
</tr>
</c:forEach>
${allBook.title}
</c:forEach>
LZ试试 allBook是你session中设置的集合名称吗
这两个名称换一下