Daten Binding Fehler im Frühjahr mvc

Ich versuche eine einfache Form mit form Tag im Frühjahr MVC erstellen. Es gibt nur ein Feld namens uname für die Übergabe des Benutzernamens.
Im ganzen Programm verwende ich Java-basierte Anmerkungen und keine XML-Dateien, aber ich bekomme diesen ärgerlichen Fehler und weiß nicht, wie ich ihn beheben kann.Daten Binding Fehler im Frühjahr mvc

SEVERE: Neither BindingResult nor plain target object for bean name 'user' available as request attribute 
java.lang.IllegalStateException: Neither BindingResult nor plain target object for bean name 'user' available as request attribute 
    at org.springframework.web.servlet.support.BindStatus.<init>(BindStatus.java:144) 
    at org.springframework.web.servlet.tags.form.AbstractDataBoundFormElementTag.getBindStatus(AbstractDataBoundFormElementTag.java:168) 
    at org.springframework.web.servlet.tags.form.AbstractDataBoundFormElementTag.getPropertyPath(AbstractDataBoundFormElementTag.java:188) 
    at org.springframework.web.servlet.tags.form.AbstractDataBoundFormElementTag.getName(AbstractDataBoundFormElementTag.java:154) 
    at org.springframework.web.servlet.tags.form.AbstractDataBoundFormElementTag.autogenerateId(AbstractDataBoundFormElementTag.java:141) 
    at org.springframework.web.servlet.tags.form.AbstractDataBoundFormElementTag.resolveId(AbstractDataBoundFormElementTag.java:132) 
    at org.springframework.web.servlet.tags.form.AbstractDataBoundFormElementTag.writeDefaultAttributes(AbstractDataBoundFormElementTag.java:116) 
    at org.springframework.web.servlet.tags.form.AbstractHtmlElementTag.writeDefaultAttributes(AbstractHtmlElementTag.java:422) 
    at org.springframework.web.servlet.tags.form.InputTag.writeTagContent(InputTag.java:142) 
    at org.springframework.web.servlet.tags.form.AbstractFormTag.doStartTagInternal(AbstractFormTag.java:84) 
    at org.springframework.web.servlet.tags.RequestContextAwareTag.doStartTag(RequestContextAwareTag.java:80) 
    at org.apache.jsp.Home_jsp._jspx_meth_form_005finput_005f0(Home_jsp.java:213) 
    at org.apache.jsp.Home_jsp._jspx_meth_form_005fform_005f0(Home_jsp.java:177) 
    at org.apache.jsp.Home_jsp._jspService(Home_jsp.java:132) 
    at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70) 
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:729) 
    at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:438) 
    at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:396) 
    at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:340) 
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:729) 
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:292) 
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207) 
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) 
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240) 
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207) 
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:212) 
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106) 
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502) 
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:141) 
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79) 
    at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:616) 
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88) 
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:522) 
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1095) 
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:672) 
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1500) 
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1456) 
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) 
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) 
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) 
    at java.lang.Thread.run(Thread.java:745) 

Jun 07, 2016 1:56:33 AM org.apache.catalina.core.StandardWrapperValve invoke 
SEVERE: Servlet.service() for servlet [jsp] in context with path [/first] threw exception [An exception occurred processing JSP page /Home.jsp at line 14 

11: <body> 
12: <form:form method="post" action="vv" commandName="user"> 
13: Name: 
14: <form:input path="uname"/> 
15: <input type="submit" value="Login"/> 
16: 
17: </form:form> 


Stacktrace:] with root cause 
java.lang.IllegalStateException: Neither BindingResult nor plain target object for bean name 'user' available as request attribute 
    at org.springframework.web.servlet.support.BindStatus.<init>(BindStatus.java:144) 
    at org.springframework.web.servlet.tags.form.AbstractDataBoundFormElementTag.getBindStatus(AbstractDataBoundFormElementTag.java:168) 
    at org.springframework.web.servlet.tags.form.AbstractDataBoundFormElementTag.getPropertyPath(AbstractDataBoundFormElementTag.java:188) 
    at org.springframework.web.servlet.tags.form.AbstractDataBoundFormElementTag.getName(AbstractDataBoundFormElementTag.java:154) 
    at org.springframework.web.servlet.tags.form.AbstractDataBoundFormElementTag.autogenerateId(AbstractDataBoundFormElementTag.java:141) 
    at org.springframework.web.servlet.tags.form.AbstractDataBoundFormElementTag.resolveId(AbstractDataBoundFormElementTag.java:132) 
    at org.springframework.web.servlet.tags.form.AbstractDataBoundFormElementTag.writeDefaultAttributes(AbstractDataBoundFormElementTag.java:116) 
    at org.springframework.web.servlet.tags.form.AbstractHtmlElementTag.writeDefaultAttributes(AbstractHtmlElementTag.java:422) 
    at org.springframework.web.servlet.tags.form.InputTag.writeTagContent(InputTag.java:142) 
    at org.springframework.web.servlet.tags.form.AbstractFormTag.doStartTagInternal(AbstractFormTag.java:84) 
    at org.springframework.web.servlet.tags.RequestContextAwareTag.doStartTag(RequestContextAwareTag.java:80) 
    at org.apache.jsp.Home_jsp._jspx_meth_form_005finput_005f0(Home_jsp.java:213) 
    at org.apache.jsp.Home_jsp._jspx_meth_form_005fform_005f0(Home_jsp.java:177) 
    at org.apache.jsp.Home_jsp._jspService(Home_jsp.java:132) 
    at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70) 
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:729) 
    at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:438) 
    at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:396) 
    at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:340) 
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:729) 
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:292) 
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207) 
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) 
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240) 
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207) 
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:212) 
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106) 
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502) 
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:141) 
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79) 
    at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:616) 
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88) 
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:522) 
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1095) 
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:672) 
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1500) 
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1456) 
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) 
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) 
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) 
    at java.lang.Thread.run(Thread.java:745)

Home.jsp

%@ page language="java" contentType="text/html; charset=ISO-8859-1" 
    pageEncoding="ISO-8859-1"%> 
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> 
<%@taglib uri="http://www.springframework.org/tags/form" prefix="form"%> 

<html> 
<head> 
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> 
<title>Insert title here</title> 
</head> 
<body> 
<form:form method="post" action="vv" commandName="user"> 
Name: 
<form:input path="uname"/> 
<input type="submit" value="Login"/> 

</form:form> 
</body> 
</html>

-Controller

package one; 

import org.springframework.stereotype.Controller; 
import org.springframework.ui.ModelMap; 
import org.springframework.validation.BindingResult; 
import org.springframework.web.bind.annotation.ModelAttribute; 
import org.springframework.web.bind.annotation.RequestMapping; 
import org.springframework.web.bind.annotation.RequestMethod; 

@Controller 
@RequestMapping("vv") 
public class MainC { 

    @RequestMapping(method=RequestMethod.GET) 
    public String pp(ModelMap m) 
    { 
     User u=new User(); 
     m.addAttribute("user",u); 
     return "Home"; 
    } 
    @RequestMapping(method=RequestMethod.POST) 
    public String pp1(@ModelAttribute("user") User user, BindingResult br) 
    { 
     if(user.getUname().length()!=0) 
     return "Success"; 
     else 
      return "Failure"; 

    } 

}

Konfiguration

package one; 

import org.springframework.context.annotation.Bean; 
import org.springframework.context.annotation.ComponentScan; 
import org.springframework.context.annotation.Configuration; 
import org.springframework.web.servlet.config.annotation.EnableWebMvc; 
import org.springframework.web.servlet.view.InternalResourceViewResolver; 

@Configuration 
@EnableWebMvc 
@ComponentScan(basePackages={"one"}) 
public class Conf { 

    @Bean(name="viewResolver") 
    public InternalResourceViewResolver ii() 
    { 
     InternalResourceViewResolver i=new InternalResourceViewResolver(); 
     i.setPrefix("/"); 
     i.setSuffix(".jsp"); 
     return i; 
    } 

}

initialiser

package one; 

import javax.servlet.ServletContext; 
import javax.servlet.ServletException; 
import javax.servlet.ServletRegistration; 

import org.springframework.web.WebApplicationInitializer; 
import org.springframework.web.context.ContextLoaderListener; 
import org.springframework.web.context.support.AnnotationConfigWebApplicationContext; 
import org.springframework.web.servlet.DispatcherServlet; 

public class WebInit implements WebApplicationInitializer { 

    @Override 
    public void onStartup(ServletContext arg0) throws ServletException { 
     // TODO Auto-generated method stub 

     AnnotationConfigWebApplicationContext cxt=new AnnotationConfigWebApplicationContext(); 
     cxt.register(Conf.class); 
     arg0.addListener(new ContextLoaderListener(cxt)); 
     ServletRegistration.Dynamic srv=arg0.addServlet("HelloWeb", new DispatcherServlet(cxt)); 
     srv.setLoadOnStartup(1); 
     srv.addMapping("/"); 


    } 

}

Benutzer

package one; 

public class User { 

    private String uname; 


    public void setUname(String uname) { 
     this.uname = uname; 
    } 

    public String getUname() { 
     return uname; 
    } 

}

Quelle

2016-06-06 Neeraj

Mögliches Duplikat [weder BindingResult noch schlicht Zielobjekt für Bohnennamen als Anforderungsattribut] (http://stackoverflow.com/questions/8781558/neither-bindingresult-nor- plain-target-object-für-bean-name-available-as-request) –

In Ihrer Formulardefinition haben Sie action = "vv", aber in der Controller-Definition haben Sie @RequestMapping ("/ Home.jsp"), denke ich Sie müssen das Anforderungsmapping in vv ändern. – reos

@reos Ich versuchte es auch mit "vv". Aber immer noch denselben Fehler. – Neeraj

Das Problem war, dass das Verfahren, das das leere Bean-Objekt stellt wurde nie ausgeführt zu werden. Deshalb kam der Fehler: Ein einfaches Zielobjekt für den Bean-Namen 'Benutzer' war nicht verfügbar.

Lösung

Add a new jsp page -index.jsp which will be the home page for your application and in it add just one line in <body> 
<a href=Home>Home Page</a> 

And then in controller class... 
@RequestMapping("/Home") 
public String pp(Model m) 
{ 
User u=new User(); 
m.addAtribute("command",u); 
return "Home"; 
} 


It will solve the issue.

Quelle

2016-06-09 20:27:38 Neeraj

Daten Binding Fehler im Frühjahr mvc

Antwort

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