HTTP状态500 - 在mvc项目的第23行处理JSP页面/WEB-INF/views/home.jsp时发生异常

Question

我正在Spring工具套件中创建一个注册表单。创建项目后运行正常。它会在运行时显示欢迎信息。但每当我用jsp和spring标签库创建主页时，它都会出现以下错误

HTTP状态500 - 在第23行处理JSP页面/WEB-INF/views/home.jsp时发生异常

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HTTP Status 500 - An exception occurred processing JSP page /WEB-INF/views/home.jsp at line 23

type Exception report

message An exception occurred processing JSP page /WEB-INF/views/home.jsp at line 23

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

exception

org.apache.jasper.JasperException: An exception occurred processing JSP page /WEB-INF/views/home.jsp at line 23

20:   
21:    <table width="400px" height="150px">
22:     <tr>
23:      <td><form:label path="firstName">First Name</form:label>
24:      </td>
25:      <td><form:input path="firstName" />
26:      </td>


Stacktrace:
	org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:568)
	org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:465)
	org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:405)
	org.apache.jasper.servlet.JspServlet.service(JspServlet.java:349)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:725)
	org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
	org.springframework.web.servlet.view.InternalResourceView.renderMergedOutputModel(InternalResourceView.java:238)
	org.springframework.web.servlet.view.AbstractView.render(AbstractView.java:262)
	org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1180)
	org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:950)
	org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:852)
	org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:882)
	org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:778)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:618)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:725)
	org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

root cause

java.lang.IllegalStateException: Neither BindingResult nor plain target object for bean name 'firstName' available as request attribute
	org.springframework.web.servlet.support.BindStatus.<init>(BindStatus.java:141)
	org.springframework.web.servlet.tags.form.AbstractDataBoundFormElementTag.getBindStatus(AbstractDataBoundFormElementTag.java:178)
	org.springframework.web.servlet.tags.form.AbstractDataBoundFormElementTag.getPropertyPath(AbstractDataBoundFormElementTag.java:198)
	org.springframework.web.servlet.tags.form.LabelTag.autogenerateFor(LabelTag.java:129)
	org.springframework.web.servlet.tags.form.LabelTag.resolveFor(LabelTag.java:119)
	org.springframework.web.servlet.tags.form.LabelTag.writeTagContent(LabelTag.java:89)
	org.springframework.web.servlet.tags.form.AbstractFormTag.doStartTagInternal(AbstractFormTag.java:102)
	org.springframework.web.servlet.tags.RequestContextAwareTag.doStartTag(RequestContextAwareTag.java:79)
	org.apache.jsp.WEB_002dINF.views.home_jsp._jspx_meth_form_005flabel_005f0(home_jsp.java:188)
	org.apache.jsp.WEB_002dINF.views.home_jsp._jspService(home_jsp.java:99)
	org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:725)
	org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:432)
	org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:405)
	org.apache.jasper.servlet.JspServlet.service(JspServlet.java:349)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:725)
	org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
	org.springframework.web.servlet.view.InternalResourceView.renderMergedOutputModel(InternalResourceView.java:238)
	org.springframework.web.servlet.view.AbstractView.render(AbstractView.java:262)
	org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1180)
	org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:950)
	org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:852)
	org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:882)
	org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:778)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:618)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:725)
	org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

note The full stack trace of the root cause is available in the Apache Tomcat/8.0.9 logs.
Apache Tomcat/8.0.9

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当我从表中删除字段时，它运行良好显示hrading等。但是在创建字段时它会给出错误

回到Home.jsp

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<%@ page language="java" contentType="text/html; charset=UTF-8"
 pageEncoding="UTF-8"%>
<%@ taglib uri="http://www.springframework.org/tags/form" prefix="form"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Being Java Guys | Registration Form</title>
</head>
<body>
 <center>

  <div style="color: teal; font-size: 30px">Being Java Guys |
   Registration Form</div>



  <c:url var="userRegistration" value="saveUser.html" />
  
   <table width="400px" height="150px">
    <tr>
     <td><form:label path="firstName">First Name</form:label>
     </td>
     <td><form:input path="firstName" />
     </td>
    </tr>
    <tr>
     <td><form:label path="lastName">Last Name</form:label>
     </td>
     <td><form:input path="lastName" />
     </td>
    </tr>
    
     <td><input type="submit" value="Register" /></td>
    </tr>
   </table>
  
  <a href="list">Click Here to see User List</a>
 </center>
</body>
</html>

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控制器类

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package com.spring.controller;

import java.text.DateFormat;
import java.util.Date;
import java.util.Locale;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;

/**
 * Handles requests for the application home page.
 */
@Controller
public class HomeController {
	
	private static final Logger logger = LoggerFactory.getLogger(HomeController.class);
	
	
	@RequestMapping(method = RequestMethod.GET, value = "/")
	public String home(){
		return "home";
	}
	
}

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的pom.xml

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<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
	<modelVersion>4.0.0</modelVersion>
	<groupId>com.spring</groupId>
	<artifactId>controller</artifactId>
	<name>SpringHibernate</name>
	<packaging>war</packaging>
	<version>1.0.0-BUILD-SNAPSHOT</version>
	<properties>
		<java-version>1.6</java-version>
		<org.springframework-version>3.1.1.RELEASE</org.springframework-version>
		<org.aspectj-version>1.6.10</org.aspectj-version>
		<org.slf4j-version>1.6.6</org.slf4j-version>
	</properties>
	<dependencies>
		<!-- Spring -->
		<dependency>
			<groupId>org.springframework</groupId>
			<artifactId>spring-context</artifactId>
			<version>${org.springframework-version}</version>
			<exclusions>
				<!-- Exclude Commons Logging in favor of SLF4j -->
				<exclusion>
					<groupId>commons-logging</groupId>
					<artifactId>commons-logging</artifactId>
				 </exclusion>
			</exclusions>
		</dependency>
		<dependency>
			<groupId>org.springframework</groupId>
			<artifactId>spring-webmvc</artifactId>
			<version>${org.springframework-version}</version>
		</dependency>
				
		<!-- AspectJ -->
		<dependency>
			<groupId>org.aspectj</groupId>
			<artifactId>aspectjrt</artifactId>
			<version>${org.aspectj-version}</version>
		</dependency>	
		
		<!-- Logging -->
		<dependency>
			<groupId>org.slf4j</groupId>
			<artifactId>slf4j-api</artifactId>
			<version>${org.slf4j-version}</version>
		</dependency>
		<dependency>
			<groupId>org.slf4j</groupId>
			<artifactId>jcl-over-slf4j</artifactId>
			<version>${org.slf4j-version}</version>
			<scope>runtime</scope>
		</dependency>
		<dependency>
			<groupId>org.slf4j</groupId>
			<artifactId>slf4j-log4j12</artifactId>
			<version>${org.slf4j-version}</version>
			<scope>runtime</scope>
		</dependency>
		<dependency>
			<groupId>log4j</groupId>
			<artifactId>log4j</artifactId>
			<version>1.2.15</version>
			<exclusions>
				<exclusion>
					<groupId>javax.mail</groupId>
					<artifactId>mail</artifactId>
				</exclusion>
				<exclusion>
					<groupId>javax.jms</groupId>
					<artifactId>jms</artifactId>
				</exclusion>
				<exclusion>
					<groupId>com.sun.jdmk</groupId>
					<artifactId>jmxtools</artifactId>
				</exclusion>
				<exclusion>
					<groupId>com.sun.jmx</groupId>
					<artifactId>jmxri</artifactId>
				</exclusion>
			</exclusions>
			<scope>runtime</scope>
		</dependency>

		<!-- @Inject -->
		<dependency>
			<groupId>javax.inject</groupId>
			<artifactId>javax.inject</artifactId>
			<version>1</version>
		</dependency>
				
		<!-- Servlet -->
		<dependency>
			<groupId>javax.servlet</groupId>
			<artifactId>servlet-api</artifactId>
			<version>2.5</version>
			<scope>provided</scope>
		</dependency>
		<dependency>
			<groupId>javax.servlet.jsp</groupId>
			<artifactId>jsp-api</artifactId>
			<version>2.1</version>
			<scope>provided</scope>
		</dependency>
		<dependency>
			<groupId>javax.servlet</groupId>
			<artifactId>jstl</artifactId>
			<version>1.2</version>
		</dependency>
	
		<!-- Test -->
		<dependency>
			<groupId>junit</groupId>
			<artifactId>junit</artifactId>
			<version>4.7</version>
			<scope>test</scope>
		</dependency>        
	</dependencies>
    <build>
        <plugins>
            <plugin>
                <artifactId>maven-eclipse-plugin</artifactId>
                <version>2.9</version>
                <configuration>
                    <additionalProjectnatures>
                        <projectnature>org.springframework.ide.eclipse.core.springnature</projectnature>
                    </additionalProjectnatures>
                    <additionalBuildcommands>
                        <buildcommand>org.springframework.ide.eclipse.core.springbuilder</buildcommand>
                    </additionalBuildcommands>
                    <downloadSources>true</downloadSources>
                    <downloadJavadocs>true</downloadJavadocs>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>2.5.1</version>
                <configuration>
                    <source>1.6</source>
                    <target>1.6</target>
                    <compilerArgument>-Xlint:all</compilerArgument>
                    <showWarnings>true</showWarnings>
                    <showDeprecation>true</showDeprecation>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.codehaus.mojo</groupId>
                <artifactId>exec-maven-plugin</artifactId>
                <version>1.2.1</version>
                <configuration>
                    <mainClass>org.test.int1.Main</mainClass>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

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Servlet的context.xml中

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<?xml version="1.0" encoding="UTF-8"?>
<beans:beans xmlns="http://www.springframework.org/schema/mvc"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xmlns:beans="http://www.springframework.org/schema/beans"
	xmlns:context="http://www.springframework.org/schema/context"
	xsi:schemaLocation="http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd
		http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
		http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">

	<!-- DispatcherServlet Context: defines this servlet's request-processing infrastructure -->
	
	<!-- Enables the Spring MVC @Controller programming model -->
	<annotation-driven />

	<!-- Handles HTTP GET requests for /resources/** by efficiently serving up static resources in the ${webappRoot}/resources directory -->
	<resources mapping="/resources/**" location="/resources/" />

	<!-- Resolves views selected for rendering by @Controllers to .jsp resources in the /WEB-INF/views directory -->
	<beans:bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
		<beans:property name="prefix" value="/WEB-INF/views/" />
		<beans:property name="suffix" value=".jsp" />
	</beans:bean>
	
	<context:component-scan base-package="com.spring.controller" />
	
	
	
</beans:beans>

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Answer 1

您的配置是正确的，但是，您的控制器存在问题，负责返回视图的控制器应该返回一个 ModelAndView 实例。收到请求后，任何 BaseCommandController 将尝试使用请求参数填充命令对象。这是使用典型且众所周知的 JavaBeans 属性表示法完成的。当名为“firstName”的请求参数存在时，框架将尝试调用 setFirstName([value]) 传递参数值。当然支持嵌套属性。例如，名为“address.city”的参数将导致对命令类的 getAddress().setCity([value]) 调用。 form-tags 默认模型属性命令。您应该使用以下代码替换您的控制器：

    @RequestMapping(method = RequestMethod.GET, value = "/")
public ModelAndView personForm(Locale locale, Model model) {
    return new ModelAndView("home","command", new User());
}

“home”是您指向的视图 “命令”是默认模型属性 “new User()”是包含属性的setter和getter的实例。 在包含表单的视图中，您必须确保路径属性的值在 User 类中应该有 setter 和 getter。<form:input path="firstName" />，例如 firstName 应该等于 User 类中的 firstName 属性而且它应该有 setter 和 getter。

参考：https://docs.spring.io/spring-framework/docs/1.2.9/javadoc-api/org/springframework/web/servlet/mvc/BaseCommandController.html