关于Neither BindingResult nor plain target object
javax.servlet.ServletException:Neither BindingResult nor plain target object for bean name 'loginForm'available as request attribute
从异常信息中是“loginForm”的绑定出了问题，一开始怀疑是login.jsp绑定错误或者是配
置文件中控制器的commandName属性出错，但无论怎么修改仍然不能避免这个异常的抛出，在
网上查，这个异常出现也不少，就是解决的方法比较表示的不够明了（现在回过头来觉得就
像网上说的那么回事，可能当时是自己比较浮躁了），找了个可以成功运行的实例来做对
比。最后发现是有下面这么个原因可以导致这个异常
表单页面通过非表单控制器转发（我个人出错的主要原因）
对这个异常抛出的实验
web.xml如下
<?xml version="1.0" encoding="ISO-8859-1"?>
<!DOCTYPE web-app
PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
"http://java.sun.com/dtd/web-app_2_3.dtd">
<web-app>
<servlet>
<servlet-name>testapp</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>testapp</servlet-name>
<url-pattern>*.do</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
<taglib>
<taglib-uri>/spring</taglib-uri>
<taglib-location>/WEB-INF/spring.tld</taglib-location>
</taglib>
</web-app>
testapp-servlet.xml如下
<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd"> <beans> <bean id="loginController" class="cot.LoginController"> <property name="successView" value="success"/> <property name="formView" value="login"/> <property name="commandName" value="loginForm"/> </bean> <bean id="redirectController" class="cot.RedirectController"> <property name="successView" value="login"/> </bean> <bean id="urlMapping" class="org.springframework.web.servlet.handler.SimpleUrlHandlerMapping"> <property name="mappings"> <props> <prop key="/login.do">loginController</prop> <prop key="/redirect.do">redirectController</prop> </props> </property> </bean> <bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver"> <property name="viewClass"> <value>org.springframework.web.servlet.view.JstlView</value> </property> <property name="prefix"> <value>/WEB-INF/jsp/</value> </property> <property name="suffix"> <value>.jsp</value> </property> </bean> </beans>
index.jsp如下
<%@ taglib prefix="c" uri="http://java.sun.com/jstl/core" %> <%@ taglib prefix="fmt" uri="http://java.sun.com/jstl/fmt" %> <%@ taglib prefix="spring" uri="/spring"%> <a href="login.do">login</a> <a href="redirect.do">redirect</a>
login.jsp如下
<%@ include file="/WEB-INF/jsp/include.jsp" %>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<title>无标题文档</title>
</head>
<body>
<form method="post" action="login.do">
<table width="95%" bgcolor="f8f8ff" border="0" cellspacing="0" cellpadding="5">
<tr>
<td alignment="right" width="20%">Serial:</td>
<spring:bind path="loginForm.serial">
<td width="20%"><input type="text" name="serial" value="<c:out value="${status.value}"/>"></td>
<td width="60%">
<font color="red"><c:out value="${status.errorMessage}"/></font></td>
</spring:bind>
</tr>
</table>
<table width="95%" bgcolor="f8f8ff" border="0" cellspacing="0" cellpadding="5">
<tr>
<td alignment="right" width="20%">Key:</td>
<spring:bind path="loginForm.key">
<td width="20%"><input type="text" name="key" value="<c:out value="${status.value}"/>"></td>
<td width="60%">
<font color="red"><c:out value="${status.errorMessage}"/></font></td>
</spring:bind>
</tr>
</table>
<br>
<spring:hasBindErrors name="loginForm.*">
<b>Please fix all errors!</b>
</spring:hasBindErrors>
<br><br>
<input type="submit" alignment="center" value="Execute">
</form>
</body>
</html>
RedirectController.java
package cot;
import org.springframework.web.servlet.mvc.Controller;
import org.springframework.web.servlet.ModelAndView;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
public class RedirectController implements Controller{
private String successView;
public ModelAndView handleRequest(HttpServletRequest request,HttpServletResponse response)
throws ServletException,IOException{
return new ModelAndView(getSuccessView());
}
public String getSuccessView(){
return successView;
}
public void setSuccessView(String successView){
this.successView=successView;
}
}
LoginController.java如下
package cot;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import bus.IUserDAO;
import web.User;
import org.springframework.validation.BindException;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.mvc.SimpleFormController;
public class LoginController extends SimpleFormController{
public LoginController(){
setCommandClass(LoginForm.class);
}
protected ModelAndView onSubmit(HttpServletRequest request,HttpServletResponse response,
Object command,BindException exception) throws Exception{
return new ModelAndView(getSuccessView());
}
}
LoginForm.java如下
package cot;
public class LoginForm{
private String serial;
private String key;
public String getSerial(){
return serial;
}
public void setSerial(String serial){
this.serial=serial;
}
public String getKey(){
return key;
}
public void set(String key){
this.key=key;
}
}
不可避免，文中出错...