Spring sf:form等标签使用不了(JSP页面声明了引用)

type Exception report

message /login.jsp (line: 13, column: 1) Unable to load tag handler class "org.springframework.web.servlet.tags.form.FormTag" for tag "sf:form"

description The server encountered an internal error that prevented it from fulfilling this request.

exception

org.apache.jasper.JasperException: /login.jsp (line: 13, column: 1) Unable to load tag handler class "org.springframework.web.servlet.tags.form.FormTag" for tag "sf:form"
org.apache.jasper.compiler.DefaultErrorHandler.jspError(DefaultErrorHandler.java:42)
org.apache.jasper.compiler.ErrorDispatcher.dispatch(ErrorDispatcher.java:408)
org.apache.jasper.compiler.ErrorDispatcher.jspError(ErrorDispatcher.java:199)
org.apache.jasper.compiler.Parser.parseCustomTag(Parser.java:1226)
org.apache.jasper.compiler.Parser.parseElements(Parser.java:1452)
org.apache.jasper.compiler.Parser.parse(Parser.java:138)
org.apache.jasper.compiler.ParserController.doParse(ParserController.java:242)
org.apache.jasper.compiler.ParserController.parse(ParserController.java:102)
org.apache.jasper.compiler.Compiler.generateJava(Compiler.java:198)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:373)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:353)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:340)
org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:646)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:357)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)
javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
note The full stack trace of the root cause is available in the Apache Tomcat/7.0.30 logs.

<%@ taglib prefix="sf" uri="http://www.springframework.org/tags/form"%> 顶部少了这个语句吧。