我在Spring中面临一个动态列表绑定的问题。我正在尝试创建一个“添加联系人”页面,该页面基本上如下所示:
当“添加电话”按钮被点击,我希望另一个“电话类型”和“电话号码”按钮出现在下面,以便用户可以输入多个电话号码。这就是我面临问题的地方。
下面是我的代码:
@Entity
@Table(name = "CONTACTS_JPA2")
public class Contact {
@Id
@Column(name = "CONTACT_ID")
@GeneratedValue
private int Id;
@Column(name = "FIRST_NAME")
private String firstname;
@Column(name = "LAST_NAME")
private String lastname;
@SuppressWarnings("unchecked")
@OneToMany(mappedBy = "contact", cascade = CascadeType.ALL)
private List<Phone> phones = LazyList.decorate(new ArrayList<Phone>(),FactoryUtils.instantiateFactory(Phone.class));
@Column(name = "EMAIL_ID")
private String emailid;
@Column(name = "BIRTHDAY")
private Date birthday;
/*Getters and Setters*/
}
@Entity
@Table(name = "PHONE")
public class Phone {
@Id
@Column(name = "ID")
private int Id;
@Column(name = "PHONE_NBR")
private String phonenumber;
@Column(name = "PHONE_TYPE")
private String phonetype;
@ManyToOne()
@JoinColumn(name = "CONTACT_ID")
private Contact contact;
/*Getters and Setter*/
}
<form:form id = "addcontactform" name="addcontact" method="POST" commandName="contact">
<table>
<tr>
<td>First Name:</td>
<td><form:input name = "firstname" id = "firstname" path="firstname" value=''/></td>
<td>Last Name:</td>
<td><form:input name = "lastname" id = "lastname" path="lastname" value=''/></td>
</tr>
<tr>
<td>Email:</td>
<td><form:input name = "emailid" id = "emailid" path="emailid"/></td>
</tr>
<tr>
<td>Phone Type:</td>
<td>
<spring:bind path = "contact.phones[0].phonetype">
<form:select id ="phonetype" name="phonetype" path="${status.expression}">
<option value="-- Select Phone Type --">-- Select Phone Type --</option>
<option value="Home">Home</option>
<option value="Cell">Cell</option>
<option value="Work">Work</option>
</form:select>
</spring:bind>
</td>
<td>Phone Number:</td>
<td>
<spring:bind path = "contact.phones[0].phonenumber">
<form:input name = "phonenumber" id = "phonenumber" path="${status.expression}" value=''/>
</spring:bind>
</td>
<td><form:button type = "button" id = "addphone">Add Phone</form:button>
</tr>
<tr>
<td>Birthday:</td>
<td><form:input id = "birthday" path="birthday" value=''/></td>
</tr>
</table>
</div>
<input type="submit" id = "mysubmit" name="mysubmit" value="Add Contact" />
</div>
</form:form>
以上表单上的Javascript:
我在这里尝试做的是,当单击“Add Phone”按钮时,我向服务器发出一个AJAX请求,其中包含要插入的行的计数。
<script type="text/javascript" src="${pageContext.request.contextPath}/resources/scripts/jquery.min.js"></script>
<script type="text/javascript">
$(document).ready(function(){
$('#addphone').click(function(){
phonecount++;
alert('Addinh phone '+phonecount);
$.get("displayaddphone", {count : phonecount},callback);
function callback(data){
alert('in Callback');
$("#addphone").before(data);
};
return false;
});
</script>
在AJAX请求中调用的Controller方法:它将行计数添加到模型中,并返回一个jsp-AddNewPhone.jsp
@RequestMapping(value = "/displayaddphone")
public String appendaddphone(@RequestParam(value="count") int addphonecount,ModelMap model){
model.addAttribute("addphonecount", addphonecount);
return "addnewphone";
}
<%@ taglib uri="http://www.springframework.org/tags/form" prefix="form"%>
<%@ taglib uri="http://www.springframework.org/tags" prefix="spring" %>
<tr>
<td>Phone Type:</td>
<td>
<form:select id ="phonetype" name="phonetype" path="contact.phones[${addphnbr}].phonetype">
<option value="-- Select Phone Type --">-- Select Phone Type --</option>
<option value="Home">Home</option>
<option value="Cell">Cell</option>
<option value="Work">Work</option>
</form:select>
</td>
<td>Phone Number:</td>
<td>
<form:input name = "phonenumber" id = "phonenumber" path="contact.phones[${addphnbr}].phonenumber" value=''/>
</td>
</tr>
SEVERE: Servlet.service() for servlet [appServlet] in context with path [/ContactList-JPA2] threw exception [java.lang.IllegalStateException: Neither BindingResult nor plain target object for bean name 'contact' available as request attribute] with root cause
java.lang.IllegalStateException: Neither BindingResult nor plain target object for bean name 'contact' available as request attribute
at org.springframework.web.servlet.support.BindStatus.<init>(BindStatus.java:141)
at org.springframework.web.servlet.tags.form.AbstractDataBoundFormElementTag.getBindStatus(Abs tractDataBoundFormElementTag.java:178)
at org.springframework.web.servlet.tags.form.AbstractDataBoundFormElementTag.getPropertyPath(AbstractDataBoundFormElementTag.java:198)
at org.springframework.web.servlet.tags.form.AbstractDataBoundFormElementTag.getName(AbstractDataBoundFormElementTag.java:164)
at org.springframework.web.servlet.tags.form.AbstractDataBoundFormElementTag.writeDefaultAttributes(AbstractDataBoundFormElementTag.java:127)
at org.springframework.web.servlet.tags.form.AbstractHtmlElementTag.writeDefaultAttributes(AbstractHtmlElementTag.java:421)
at org.springframework.web.servlet.tags.form.SelectTag.writeTagContent(SelectTag.java:199)
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.views.addnewphone_jsp._jspx_meth_form_005fselect_005f0(addnewphone_jsp.java:117)
at org.apache.jsp.WEB_002dINF.views.addnewphone_jsp._jspService(addnewphone_jsp.java:76)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:432)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:690)
at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:477)
at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:402)
at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:329)
at org.springframework.web.servlet.view.InternalResourceView.renderMergedOutputModel(InternalResourceView.java:238)
at org.springframework.web.servlet.view.AbstractView.render(AbstractView.java:262)
at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1157)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:927)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:827)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:882)
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:778)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:311)
at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:116)
at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:83)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:323)
at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:113)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:323)
at org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:101)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:323)
at org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:113)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:323)
at org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:54)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:323)
at org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:45)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:323)
at org.springframework.security.web.authentication.www.BasicAuthenticationFilter.doFilter(BasicAuthenticationFilter.java:150)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:323)
at org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:182)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:323)
at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:105)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:323)
at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:87)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:323)
at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:173)
at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:346)
at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:259)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:225)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:168)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:98)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:927)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at com.springsource.insight.collection.tcserver.request.HttpRequestOperationCollectionValve.invoke(HttpRequestOperationCollectionValve.java:88)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1001)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:585)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:312)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
at java.lang.Thread.run(Thread.java:722)
基本上,我试图在一个单独的jsp中构建我想要在主页面中添加的HTML,并尝试将其动态添加到表单中。这对我的情况来说是正确的方法吗。请指教。
您正在JSP中接受类似contact.phones[${addphnbr}].phoneType的内容。并且您的控制器没有将此信息与JSP一起发送。这就是为什么这个错误。
您的控制器应该为您的JSP提供“contact”属性。现在,您正在将“addPhoneCount”发送到jsp,而您似乎没有在jsp上使用它。您可能需要发送“联系人”来代替。
@RequestMapping(value = "/displayaddphone")
public String appendaddphone(@RequestParam(value="count") int addphonecount,ModelMap model){
// define "contact" object, suppose for example
Contact contact = populateContact();
model.addAttribute("contact", contact);
return "addnewphone";
}
问题内容: 我对动态绑定和静态绑定感到非常困惑。我已经读过,在编译时确定对象的类型称为静态绑定,而在运行时确定它的称为动态绑定。 下面的代码会发生什么: 静态绑定还是动态绑定? 这表明什么样的多态性? 问题答案: 您的示例是 动态绑定 ,因为在运行时确定类型是什么,并调用适当的方法。 现在假设您也具有以下两种方法: 即使您更改为 这将打印出来,因为对的调用使用 静态绑定 ,并且编译器仅知道其类型。
静态绑定还是动态绑定? 这显示了什么样的多态性?
本文向大家介绍浅谈Java中的重载,重写,多态,静态绑定、动态绑定,包括了浅谈Java中的重载,重写,多态,静态绑定、动态绑定的使用技巧和注意事项,需要的朋友参考一下 本文主要研究的是关于Java中重载,重写,多态,静态绑定、动态绑定的相关内容,具体如下。 重载,英文名是overload,是指在一个类中定义了一个以上具有相同名称的方法,这些方法的参数个数、参数类型和顺序不能相同。返回类型可以相同,
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我想我得到了第一个,但在其他方面我完全迷失了。我是这样解决第一个问题的: 在运行时,的类型是,所以我们调用curly的print方法。因为我们将类型的对象传递给print,所以相应的参数类型为的print方法在中运行。此方法的输出是,正确答案。 然而,当我将此技术应用到以下行时,我最终得到了错误的答案。有人能解释一下这个概念在Java中到底是如何工作的吗? 代码的正确输出是:
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