Spring form

java.lang.IllegalStateException: Neither BindingResult nor plain target object for bean name 'user' available as request attribute
	org.springframework.web.servlet.support.BindStatus.<init>(BindStatus.java:144)
	org.springframework.web.servlet.tags.form.AbstractDataBoundFormElementTag.getBindStatus(AbstractDataBoundFormElementTag.java:168)
	org.springframework.web.servlet.tags.form.AbstractDataBoundFormElementTag.getPropertyPath(AbstractDataBoundFormElementTag.java:188)
	org.springframework.web.servlet.tags.form.AbstractDataBoundFormElementTag.getName(AbstractDataBoundFormElementTag.java:154)
	org.springframework.web.servlet.tags.form.AbstractDataBoundFormElementTag.autogenerateId(AbstractDataBoundFormElementTag.java:141)
	org.springframework.web.servlet.tags.form.AbstractDataBoundFormElementTag.resolveId(AbstractDataBoundFormElementTag.java:132)
	org.springframework.web.servlet.tags.form.AbstractDataBoundFormElementTag.writeDefaultAttributes(AbstractDataBoundFormElementTag.java:116)
	org.springframework.web.servlet.tags.form.AbstractHtmlElementTag.writeDefaultAttributes(AbstractHtmlElementTag.java:422)
	org.springframework.web.servlet.tags.form.InputTag.writeTagContent(InputTag.java:142)
	org.springframework.web.servlet.tags.form.AbstractFormTag.doStartTagInternal(AbstractFormTag.java:84)
	org.springframework.web.servlet.tags.RequestContextAwareTag.doStartTag(RequestContextAwareTag.java:80)
	org.apache.jsp.index_jsp._jspx_meth_form_005finput_005f0(index_jsp.java:186)
	org.apache.jsp.index_jsp._jspx_meth_form_005fform_005f0(index_jsp.java:141)
	org.apache.jsp.index_jsp._jspService(index_jsp.java:94)
	org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
	org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:439)
	org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:395)
	org.apache.jasper.servlet.JspServlet.service(JspServlet.java:339)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
	org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

spring form 在jsp页面必须要有相应的bean绑定，即不能直接访问页面，需由control定向，并且Model中必需有bean对象。

如：
<%@taglib prefix="form" uri="http://www.springframework.org/tags/form" %>

<form:form action="/user" commandName="user" method="post">
    name:<form:input path="name"/><br>
    phone:<form:input path="phone"/><br>
    <input type="submit" value="submit" />
</form:form>

@RequestMapping(value = "/user",method = RequestMethod.GET)
public String formpage(Model model){
    User user = new User();
    model.addAttribute("user",user);
    return "userform";
}