spring3 jsp页面使用<form:form modelAttribute="xxxx" action="xxxx">报错，附连接数据库的spring MVC annotation 案例

在写一个使用spring3 的form标签的例子时，一直报错，错误信息为：java.lang.IllegalStateException: Neither BindingResult nor plain target object for bean name 'user' available as request attribute 。具体信息为：

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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: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.LabelTag.autogenerateFor(LabelTag.java:129)

at org.springframework.web.servlet.tags.form.LabelTag.resolveFor(LabelTag.java:119)

at org.springframework.web.servlet.tags.form.LabelTag.writeTagContent(LabelTag.java:89)

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.register_jsp._jspx_meth_sf_005flabel_005f0(register_jsp.java:255)

at org.apache.jsp.WEB_002dINF.jsp.register_jsp._jspService(register_jsp.java:140)

at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)

at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:377)

at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313)

at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)

at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)

at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)

at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:646)

at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:436)

at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:374)

at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:302)

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:644)

at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:549)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:617)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)

at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)

at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)

at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)

at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)

at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)

at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)

at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)

at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:298)

at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:852)

at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:588)

at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)

at java.lang.Thread.run(Thread.java:662)

在网上找了好长时间都不是原因所在，一直在想form标签中的modelAttribute是怎么跟project中相应的类联系在一起的，同事说是根据<form:input path="field"/>中的path attribute跟相应类中的field对应起来，由spring像注入一样给每个field赋值。所以一直在JSP页面查找原因，网上找的也都是改JSP页面，结果还是没有解决掉。

错误信息是“对于bean name 'xxxx' 既没有BindingResult也没有普通的目标对象可以用来作为请求属性”。突然想到在进入form表单页面之前，要有一个'xxxx'对象才可以在表单的标签中识别出来，所以在进入该JSP页面之前的Controller类里面相应的方法里面加上一个'xxxx'的对象。解决如下：

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return new ModelAndView("register").addObject(new User());

已经验证这样修改之后就不会报错。

例子的结构如图：



web.xml 的内容：

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<?xml version="1.0" encoding="UTF-8"?>

<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"

xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
id="WebApp_ID" version="2.5">

<display-name>springMVCForm</display-name>

<servlet>

<servlet-name>springMVCForm</servlet-name>

<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>

</servlet>

<servlet-mapping>

<servlet-name>springMVCForm</servlet-name>

<url-pattern>*.do</url-pattern>

</servlet-mapping>

<context-param>

<param-name>contextConfigLocation</param-name>

<param-value>/WEB-INF/springMVCForm-servlet.xml</param-value>

</context-param>

<listener>

<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>

</listener>

<welcome-file-list>

<welcome-file>index.jsp</welcome-file>

</welcome-file-list>

</web-app>

springMVCForm-servlet.xml 的内容：

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<?xml version="1.0" encoding="UTF-8"?>

<beans xmlns="http://www.springframework.org/schema/beans"

xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:mvc="http://www.springframework.org/schema/mvc"

xmlns:context="http://www.springframework.org/schema/context"

xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd">
<mvc:annotation-driven />

<context:component-scan base-package="org.spring.wayne" />

<bean id="config"

class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">

<property name="locations">

<list>

<value>classpath:db-config.properties</value>

</list>

</property>

</bean>

<!-- 获取数据源 -->

<bean id="dataSource" class="org.apache.tomcat.dbcp.dbcp.BasicDataSource">

<property name="driverClassName">

<value>${db.dirverClass}</value>

</property>

<property name="url">

<value>${db.url}</value>

</property>

<property name="username">

<value>${db.username}</value>

</property>

<property name="password">

<value>${db.password}</value>

</property>

</bean>

<bean name="namedParameterJdbcTemplate"

class="org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate">

<constructor-arg ref="dataSource" />

</bean>

<bean name="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">

<constructor-arg ref="dataSource" />

</bean>

<bean

class="org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping" />

<bean

class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter" />

<!-- 对模型视图名称的解析，即在模型视图名称添加前后缀,在requestmapping输入的地址后自动调用该类进行视图解析 -->

<bean id="viewResolver"

class="org.springframework.web.servlet.view.InternalResourceViewResolver">

<property name="viewClass"

value="org.springframework.web.servlet.view.JstlView" />

<property name="prefix" value="/WEB-INF/jsp/" /><!-- 跳转页面的前缀路径

如 /web-inf/jsp/ -->

<property name="suffix" value=".jsp"></property><!-- 跳转页面后缀 如 helloWorld.jsp -->

</bean>

</beans>

db-config.properties的内容：

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db.url= jdbc:mysql://localhost:3306/springmvcdb?useUnicode=true&characterEncoding=utf8

db.username=root

db.password=

db.dirverClass= com.mysql.jdbc.Driver

UserDao.class的内容：

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package org.spring.wayne.dao;

import org.spring.wayne.dao.basic.BasicDao;

@Repository

public class UserDao extends BasicDao {

public void addUser(User user) {

String SQL = "INSERT INTO TBL_USER(USERNAME ,PASSWORD) VALUES('" + user.getUserName() + "' ,'"

+ user.getPassword() + "')";

getJdbcTemplate().execute(SQL);

}

}

BasicDao.class的内容：

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package org.spring.wayne.dao.basic;

import org.springframework.beans.factory.annotation.Autowired;

public class BasicDao {

@Autowired

private JdbcTemplate jdbcTemplate;

@Autowired

private NamedParameterJdbcTemplate namedParameterJdbcTemplate;

public JdbcTemplate getJdbcTemplate() {

return jdbcTemplate;

}

public void setJdbcTemplate(JdbcTemplate jdbcTemplate) {

this.jdbcTemplate = jdbcTemplate;

}

public NamedParameterJdbcTemplate getNamedParameterJdbcTemplate() {

return namedParameterJdbcTemplate;

}

public void setNamedParameterJdbcTemplate(NamedParameterJdbcTemplate namedParameterJdbcTemplate) {

this.namedParameterJdbcTemplate = namedParameterJdbcTemplate;

}

}

UserService.class的内容：

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package org.spring.wayne.service;

import org.spring.wayne.web.form.User;

public interface UserService {

public void addUser(User user);

}

UserServiceImpl.class的内容：

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package org.spring.wayne.service.impl;

import org.spring.wayne.dao.UserDao;

@Service

public class UserServiceImpl implements UserService {

@Autowired

private UserDao userDao;

@Override

public void addUser(User user) {

userDao.addUser(user);

}

}

RegController.class的内容：

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package org.spring.wayne.web.controller;

import javax.validation.Valid;

@Controller

public class RegController {

@Autowired

private UserService userService;

@RequestMapping("/register.do")

public String handler(@ModelAttribute("user") @Valid User user, BindingResult result, Model model) {

if (!result.hasErrors()) {

model.addAttribute("userName", user.getUserName());

model.addAttribute("password", user.getPassword());

userService.addUser(user);

return "welcome";

} else

return "register";

}

}

WelcomeController.class的内容：

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package org.spring.wayne.controller;

import org.spring.wayne.web.form.User;

import org.springframework.stereotype.Controller;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.servlet.ModelAndView;

@Controller

public class WelcomeController {

@RequestMapping("/welcome.do")

public ModelAndView handler() {

return new ModelAndView("register").addObject(new User());

}

}

User.class的内容：

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package org.spring.wayne.web.form;

import javax.validation.constraints.NotNull;

import javax.validation.constraints.Size;

import org.hibernate.validator.constraints.NotEmpty;

public class User {

private String errors;

@NotNull

@NotEmpty(message = "This cannot be null")

@Size(min = 4, max = 6, message = "length is wrong")

private String userName;

@NotNull

@NotEmpty

@Size(min = 6, max = 10)

private String password;

public String getUserName() {

return userName;

}

public void setUserName(String userName) {

this.userName = userName;

}

public String getPassword() {

return password;

}

public void setPassword(String password) {

this.password = password;

}

public String getErrors() {

return errors;

}

public void setErrors(String errors) {

this.errors = errors;

}

}

index.jsp的内容：

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<%@ page language="java" contentType="text/html; charset=UTF-8"

pageEncoding="UTF-8"%>

<%

String path = request.getContextPath();

String basePath = request.getScheme() + "://"

+ request.getServerName() + ":" + request.getServerPort()

+ path + "/";

%>

<!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>The Index Page</title>

</head>

<body>

<h3>

<a href="<%=basePath %>welcome.do">Click here to start</a>

</h3>

</body>

</html>

register.jsp的内容：

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<%@ page language="java" contentType="text/html; charset=UTF-8"

pageEncoding="UTF-8"%>

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

<!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>The Register Page</title>

<script type="text/javascript">

function doSubmit() {

var sf = document.getElementById("sf");

sf.submit();

}

</script>

<style type="text/css">

.errors {

font-size: 12px;

color: red;

}

</style>

</head>

<body>

<sf:form id="sf" method="POST" modelAttribute="user"

action="register.do">

<sf:errors path="errors" />

<fieldset>

<legend>Register</legend>

<table cellspacing="0">

<tr>

<td><sf:label path="userName">UserName:</sf:label>

</td>

<td><sf:input path="userName" />

</td>

<td><sf:errors path="userName" class="errors" />

</td>

</tr>

<tr>

<td><sf:label path="password">Password:</sf:label>

</td>

<td><sf:password path="password" />

</td>

<td><sf:errors path="password" class="errors" />

</td>

</tr>

<tr>

<td colspan="2"><input type="button" value="Submit"

onClick="doSubmit()">

</td>

</tr>

</table>

</fieldset>

</sf:form>

</body>

</html>

welcome.jsp的内容：

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<%@ page language="java" contentType="text/html; charset=UTF-8"

pageEncoding="UTF-8"%>

<!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>The Welcome Page</title>

</head>

<body>

Welcome, ${userName }, your password is ${password }!

<br>

<h3>This item has been inserted into the table !</h3>

</body>

</html>

用到的jar包包括spring3中的dist目录下的所有jar包，validation-api，hibernate-validator，slf4j-api，slf4j-log4j，log4j，commons-logging，tomcat-dbcp，mysql-connector-java-5.1.12-bin包。

运行截图如下：

运行project后的界面：



点击page中的链接后如图所示：



当UserName和Password为空时提示错误信息：



输入符合要求的UserName和Password跳转到下一个页面：



现在查询数据库可以看到一条记录：



该Spring MVC JUnit测试实例请点击（Spring MVC JUnit Test测试实例 附：读取WEB-INF下配置文件的方法）