BindingResult和bean名称的普通目标对象都不可用作请求属性

Question

BindingResult和bean名称的普通目标对象都不可用作请求属性

我正在学习Spring 3的注释fu的绳索,我偶然发现了newb的噩梦异常.非常感谢任何帮助.

这里是jsp代码的形式:

  <form:form method="POST" action="login.htm" modelAttribute="login">
  ....
  <form:input path="email" size="20" />
  ....

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控制器代码(此时我只是测试水域,所以不指向任何页面,只返回一个空字符串):

@Controller
@SessionAttributes
public class LoginController {

@RequestMapping(value = "/login", method = RequestMethod.POST)
public String login(    @ModelAttribute("login") Login login,
                        BindingResult result) {

    System.out.println(" email entered "+ login.getEmail()+ "\n");
    return "test";
}

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"Login"是一个带有相应setter和getter的表单bean.

我假设我的调度程序servlet中的这段代码应该处理注释扫描:

<context:component-scan
    base-package="com.testAnnFu.controller" />

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这是我尝试加载登陆jsp页面时抛出的可耻异常.

SEVERE: Neither BindingResult nor plain target object for bean name 'login' available as request attribute
java.lang.IllegalStateException: Neither BindingResult nor plain target object for bean name 'login' available as request attribute
    at org.springframework.web.servlet.support.BindStatus.<init>(BindStatus.java:141)
    at org.springframework.web.servlet.tags.form.AbstractDataBoundFormElementTag.getBindStatus(AbstractDataBoundFormElementTag.java:174)
    at org.springframework.web.servlet.tags.form.AbstractDataBoundFormElementTag.getPropertyPath(AbstractDataBoundFormElementTag.java:194)
    at org.springframework.web.servlet.tags.form.AbstractDataBoundFormElementTag.getName(AbstractDataBoundFormElementTag.java:160)
    at org.springframework.web.servlet.tags.form.AbstractDataBoundFormElementTag.autogenerateId(AbstractDataBoundFormElementTag.java:147)
    at org.springframework.web.servlet.tags.form.AbstractDataBoundFormElementTag.resolveId(AbstractDataBoundFormElementTag.java:138)
    at org.springframework.web.servlet.tags.form.AbstractDataBoundFormElementTag.writeDefaultAttributes(AbstractDataBoundFormElementTag.java:122)
    at org.springframework.web.servlet.tags.form.AbstractHtmlElementTag.writeDefaultAttributes(AbstractHtmlElementTag.java:408)
    at org.springframework.web.servlet.tags.form.InputTag.writeTagContent(InputTag.java:140)
    at org.springframework.web.servlet.tags.form.AbstractFormTag.doStartTagInternal(AbstractFormTag.java:102)
    at org.springframework.web.servlet.tags.RequestContextAwareTag.doStartTag(RequestContextAwareTag.java:79)
    at org.apache.jsp.WEB_002dINF.jsp.landing_jsp._jspx_meth_form_input_0(landing_jsp.java from :208)
    at org.apache.jsp.WEB_002dINF.jsp.landing_jsp._jspx_meth_form_form_0(landing_jsp.java from :164)
    at org.apache.jsp.WEB_002dINF.jsp.landing_jsp._jspService(landing_jsp.java from :107)
    at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:111)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:847)
    at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:403)
    at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:492)
    at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:378)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:847)
    at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1539)
    at org.apache.catalina.core.ApplicationDispatcher.doInvoke(ApplicationDispatcher.java:787)
    at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:649)
    at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:483)
    at org.apache.catalina.core.ApplicationDispatcher.doDispatch(ApplicationDispatcher.java:454)
    at org.apache.catalina.core.ApplicationDispatcher.dispatch(ApplicationDispatcher.java:350)
    at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:300)
    at org.springframework.web.servlet.view.InternalResourceView.renderMergedOutputModel(InternalResourceView.java:238)
    at org.springframework.web.servlet.view.AbstractView.render(AbstractView.java:250)
    at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1047)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:817)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:719)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:669)
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:574)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:734)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:847)
    at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1539)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:281)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
    at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:655)
    at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:595)
    at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:98)
    at com.sun.enterprise.web.PESessionLockingStandardPipeline.invoke(PESessionLockingStandardPipeline.java:91)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:162)
    at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:330)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:231)
    at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:174)
    at com.sun.grizzly.http.ProcessorTask.invokeAdapter(ProcessorTask.java:828)
    at com.sun.grizzly.http.ProcessorTask.doProcess(ProcessorTask.java:725)
    at com.sun.grizzly.http.ProcessorTask.process(ProcessorTask.java:1019)
    at com.sun.grizzly.http.DefaultProtocolFilter.execute(DefaultProtocolFilter.java:225)
    at com.sun.grizzly.DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:137)
    at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:104)
    at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:90)
    at com.sun.grizzly.http.HttpProtocolChain.execute(HttpProtocolChain.java:79)
    at com.sun.grizzly.ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:54)
    at com.sun.grizzly.SelectionKeyContextTask.call(SelectionKeyContextTask.java:59)
    at com.sun.grizzly.ContextTask.run(ContextTask.java:71)
    at com.sun.grizzly.util.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:532)
    at com.sun.grizzly.util.AbstractThreadPool$Worker.run(AbstractThreadPool.java:513)
    at java.lang.Thread.run(Thread.java:680)

WARNING: ApplicationDispatcher[/sssmgt] PWC1231: Servlet.service() for servlet jsp threw exception
java.lang.IllegalStateException: Neither BindingResult nor plain target object for bean name 'login' available as request attribute
    at org.springframework.web.servlet.support.BindStatus.<init>(BindStatus.java:141)
    at org.springframework.web.servlet.tags.form.AbstractDataBoundFormElementTag.getBindStatus(AbstractDataBoundFormElementTag.java:174)
    at org.springframework.web.servlet.tags.form.AbstractDataBoundFormElementTag.getPropertyPath(AbstractDataBoundFormElementTag.java:194)
    at org.springframework.web.servlet.tags.form.AbstractDataBoundFormElementTag.getName(AbstractDataBoundFormElementTag.java:160)
    at org.springframework.web.servlet.tags.form.AbstractDataBoundFormElementTag.autogenerateId(AbstractDataBoundFormElementTag.java:147)
    at org.springframework.web.servlet.tags.form.AbstractDataBoundFormElementTag.resolveId(AbstractDataBoundFormElementTag.java:138)
    at org.springframework.web.servlet.tags.form.AbstractDataBoundFormElementTag.writeDefaultAttributes(AbstractDataBoundFormElementTag.java:122)
    at org.springframework.web.servlet.tags.form.AbstractHtmlElementTag.writeDefaultAttributes(AbstractHtmlElementTag.java:408)
    at org.springframework.web.servlet.tags.form.InputTag.writeTagContent(InputTag.java:140)
    at org.springframework.web.servlet.tags.form.AbstractFormTag.doStartTagInternal(AbstractFormTag.java:102)
    at org.springframework.web.servlet.tags.RequestContextAwareTag.doStartTag(RequestContextAwareTag.java:79)
    at org.apache.jsp.WEB_002dINF.jsp.landing_jsp._jspx_meth_form_input_0(landing_jsp.java from :208)
    at org.apache.jsp.WEB_002dINF.jsp.landing_jsp._jspx_meth_form_form_0(landing_jsp.java from :164)
    at org.apache.jsp.WEB_002dINF.jsp.landing_jsp._jspService(landing_jsp.java from :107)
    at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:111)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:847)
    at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:403)
    at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:492)
    at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:378)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:847)
    at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1539)
    at org.apache.catalina.core.ApplicationDispatcher.doInvoke(ApplicationDispatcher.java:787)
    at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:649)
    at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:483)
    at org.apache.catalina.core.ApplicationDispatcher.doDispatch(ApplicationDispatcher.java:454)
    at org.apache.catalina.core.ApplicationDispatcher.dispatch(ApplicationDispatcher.java:350)
    at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:300)
    at org.springframework.web.servlet.view.InternalResourceView.renderMergedOutputModel(InternalResourceView.java:238)
    at org.springframework.web.servlet.view.AbstractView.render(AbstractView.java:250)
    at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1047)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:817)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:719)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:669)
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:574)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:734)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:847)
    at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1539)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:281)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
    at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:655)
    at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:595)
    at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:98)
    at com.sun.enterprise.web.PESessionLockingStandardPipeline.invoke(PESessionLockingStandardPipeline.java:91)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:162)
    at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:330)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:231)
    at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:174)
    at com.sun.grizzly.http.ProcessorTask.invokeAdapter(ProcessorTask.java:828)
    at com.sun.grizzly.http.ProcessorTask.doProcess(ProcessorTask.java:725)
    at com.sun.grizzly.http.ProcessorTask.process(ProcessorTask.java:1019)
    at com.sun.grizzly.http.DefaultProtocolFilter.execute(DefaultProtocolFilter.java:225)
    at com.sun.grizzly.DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:137)
    at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:104)
    at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:90)
    at com.sun.grizzly.http.HttpProtocolChain.execute(HttpProtocolChain.java:79)
    at com.sun.grizzly.ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:54)
    at com.sun.grizzly.SelectionKeyContextTask.call(SelectionKeyContextTask.java:59)
    at com.sun.grizzly.ContextTask.run(ContextTask.java:71)
    at com.sun.grizzly.util.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:532)
    at com.sun.grizzly.util.AbstractThreadPool$Worker.run(AbstractThreadPool.java:513)
    at java.lang.Thread.run(Thread.java:680)

WARNING: StandardWrapperValve[dispatcher]: PWC1406: Servlet.service() for servlet dispatcher threw exception
java.lang.IllegalStateException: Neither BindingResult nor plain target object for bean name 'login' available as request attribute
    at org.springframework.web.servlet.support.BindStatus.<init>(BindStatus.java:141)
    at org.springframework.web.servlet.tags.form.AbstractDataBoundFormElementTag.getBindStatus(AbstractDataBoundFormElementTag.java:174)
    at org.springframework.web.servlet.tags.form.AbstractDataBoundFormElementTag.getPropertyPath(AbstractDataBoundFormElementTag.java:194)
    at org.springframework.web.servlet.tags.form.AbstractDataBoundFormElementTag.getName(AbstractDataBoundFormElementTag.java:160)
    at org.springframework.web.servlet.tags.form.AbstractDataBoundFormElementTag.autogenerateId(AbstractDataBoundFormElementTag.java:147)
    at org.springframework.web.servlet.tags.form.AbstractDataBoundFormElementTag.resolveId(AbstractDataBoundFormElementTag.java:138)
    at org.springframework.web.servlet.tags.form.AbstractDataBoundFormElementTag.writeDefaultAttributes(AbstractDataBoundFormElementTag.java:122)
    at org.springframework.web.servlet.tags.form.AbstractHtmlElementTag.writeDefaultAttributes(AbstractHtmlElementTag.java:408)
    at org.springframework.web.servlet.tags.form.InputTag.writeTagContent(InputTag.java:140)
    at org.springframework.web.servlet.tags.form.AbstractFormTag.doStartTagInternal(AbstractFormTag.java:102)
    at org.springframework.web.servlet.tags.RequestContextAwareTag.doStartTag(RequestContextAwareTag.java:79)
    at org.apache.jsp.WEB_002dINF.jsp.landing_jsp._jspx_meth_form_input_0(landing_jsp.java from :208)
    at org.apache.jsp.WEB_002dINF.jsp.landing_jsp._jspx_meth_form_form_0(landing_jsp.java from :164)
    at org.apache.jsp.WEB_002dINF.jsp.landing_jsp._jspService(landing_jsp.java from :107)
    at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:111)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:847)
    at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:403)
    at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:492)
    at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:378)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:847)
    at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1539)
    at org.apache.catalina.core.ApplicationDispatcher.doInvoke(ApplicationDispatcher.java:787)
    at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:649)
    at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:483)
    at org.apache.catalina.core.ApplicationDispatcher.doDispatch(ApplicationDispatcher.java:454)
    at org.apache.catalina.core.ApplicationDispatcher.dispatch(ApplicationDispatcher.java:350)
    at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:300)
    at org.springframework.web.servlet.view.InternalResourceView.renderMergedOutputModel(InternalResourceView.java:238)
    at org.springframework.web.servlet.view.AbstractView.render(AbstractView.java:250)
    at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1047)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:817)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:719)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:669)
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:574)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:734)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:847)
    at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1539)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:281)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
    at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:655)
    at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:595)
    at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:98)
    at com.sun.enterprise.web.PESessionLockingStandardPipeline.invoke(PESessionLockingStandardPipeline.java:91)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:162)
    at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:330)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:231)
    at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:174)
    at com.sun.grizzly.http.ProcessorTask.invokeAdapter(ProcessorTask.java:828)
    at com.sun.grizzly.http.ProcessorTask.doProcess(ProcessorTask.java:725)
    at com.sun.grizzly.http.ProcessorTask.process(ProcessorTask.java:1019)
    at com.sun.grizzly.http.DefaultProtocolFilter.execute(DefaultProtocolFilter.java:225)
    at com.sun.grizzly.DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:137)
    at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:104)
    at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:90)
    at com.sun.grizzly.http.HttpProtocolChain.execute(HttpProtocolChain.java:79)
    at com.sun.grizzly.ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:54)
    at com.sun.grizzly.SelectionKeyContextTask.call(SelectionKeyContextTask.java:59)
    at com.sun.grizzly.ContextTask.run(ContextTask.java:71)
    at com.sun.grizzly.util.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:532)
    at com.sun.grizzly.util.AbstractThreadPool$Worker.run(AbstractThreadPool.java:513)
    at java.lang.Thread.run(Thread.java:680)

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我敲掉了表单:输入部分并有一个裸jsp页面,似乎加载.只有当我介绍输入时出错了.

我知道我对整个注释事物如何连接并映射到ModelAttribute的理解有些严重.我已经在StOv中搜索了所有组合和帖子中的类似例外情况,但我显然错过了一些东西.有人可以在这里指出我的错误吗？

Answer 1

Vin*_*nay 138

在控制器中,您需要将登录对象添加为模型的属性:

model.addAttribute("login", new Login());

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像这样:

@RequestMapping(value = "/", method = RequestMethod.GET) 
public String displayLogin(Model model) { 
    model.addAttribute("login", new Login()); 
    return "login"; 
}

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啊......基本是与你们同在,先生..所以我的问题是,我得走了着陆页,并在寻找一个预先实例模型(不具有可我),所以你的答案是现货.现在请原谅我去埋葬自己深深地陷入困境.(向视图添加模型的便捷方法是返回正确的ModelAndView对象,如下所示:**返回新的ModelAndView("登陆","登录",新登录());**) (4认同)
最后!我一直在阅读关于这个问题的文档和数百个不同的帖子,嗯...今天很长一段时间.我有完全相同的问题.感谢Vinay和Kaushik澄清并打开登陆页面! (4认同)
是; 在您调用登录视图的控制器中.LIke .. @RequestMapping(value ="/",method = RequestMethod.GET)public String displayLogin(Model model){model.addAttribute("login",new Login()); 返回"登录"; } (2认同)

Answer 2

Ani*_*kur 11

虽然做了,你会得到这个异常GET上http://localhost:8080/projectname/login

正如Vinay正确地说明你绝对可以使用

@RequestMapping(value = "/login", method = RequestMethod.GET) 
public String displayLogin(Model model) { 
    model.addAttribute("login", new Login()); 
    return "login"; 
}

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但是我将提供一些替代语法,我认为你正在尝试使用Spring 3.0.

您还可以使用以下功能实现上述功能

@RequestMapping(value = "/login", method = RequestMethod.GET) 
public String displayLogin(Login loginModel) { 
    return "login"; 
}

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它login.jsp(假设你正在使用InternalResourceViewResolver)你可以拥有

<form:form method="POST" action="login.htm" modelAttribute="login">

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注意事项:的ModelAttribute是login与不是loginModel.它是您在参数中提供的类名.但是如果你想使用loginModel modelAttribute是jsp,你可以做到以下几点

@RequestMapping(value = "/login", method = RequestMethod.GET) 
public String displayLogin(@ModelAttribute("loginModel")Login loginModel) { 
    return "login"; 
}

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和jsp会有

<form:form method="POST" action="login.htm" modelAttribute="loginModel">

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我知道做同样的事情有不同的方法.但最值得注意的是 -

Imp注意:当您在方法参数(例如public String displayLogin(Login loginModel))中添加模型类时,它会自动创建并添加到您的Model对象中(这就是您可以直接在JSP中访问它而无需手动将其放入模型中的原因).然后,如果请求具有可以使用新的ModelObject创建映射的属性,它将搜索您的请求.如果是,Spring会将请求参数中的值注入您的自定义模型对象类(在本例中为Login).

你可以通过这样做来测试

@RequestMapping(value = "/login", method = RequestMethod.GET) 
public String displayLogin(Login loginModel, Model model) { 
    System.out.println(model.asMap().get("login").equals(loginModel));
    return "login"; 
}

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注意:如果您已经给出,则上面创建新的自定义模型对象可能不成立@SessionAttributes({"login"}).在这种情况下,它将从会话中获取并填充值.

Answer 3

unk*_*own 5

第一次返回表单时，请确保传递表单所需的模型属性，这可以通过添加以下代码来完成

@RequestMapping(value = "/login", method = RequestMethod.GET)
public String login(Login login)
    return "test";
}

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默认情况下，模型属性名称被视为 Bean 类的名称，第一个小写字母

通过这样做，需要一个名为“login”的支持对象的表单将可供使用

提交表单后，您可以通过将 bean 对象和绑定结果作为方法参数传递来进行验证，如下所示

@RequestMapping(value = "/login", method = RequestMethod.POST)
public String login(    @ModelAttribute("login") Login login,
                        BindingResult result)

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