spring3 jsp页面使用报错，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：
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：
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：
<?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：
<?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：
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：
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：
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：
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：
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：
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：
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：
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：
<%@ 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：
<%@ 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：
<%@ 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）
#