在Struts2下拉列表程序中查找错误？_Struts2

在Struts2下拉列表程序中查找错误？

struts2

在Struts2下拉列表程序中查找错误？,struts2,Struts2,这三个文件是为struts2提供的。它没有提供输出。它提供 jasper异常。请查找错误 ======================== updatedesig.jsp <%@page contentType="text/html" pageEncoding="UTF-8"%> <%@taglib prefix="p" uri="/struts-tags" %> <!DOCTYPE html> <html> <head> &

这三个文件是为struts2提供的。它没有提供输出。它提供 jasper异常。请查找错误

========================

updatedesig.jsp

<%@page contentType="text/html" pageEncoding="UTF-8"%>
<%@taglib prefix="p" uri="/struts-tags" %>
<!DOCTYPE html>
<html>
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <title>JSP Page</title>
</head>
<body>
    <p:form action="count"method="post">
    <p:select name="country" list="countryList"  label="Select a country" />/*creating         list in jsp*/
    </p:form>
    <h1>Hello World!</h1>
</body>
</html>

struts.xml

<struts>

<package name="b" extends="struts-default">
<action name="count" class="b.Countr" >/*action class is Countr.java*/

  <result name="success">updatedesig.jsp</result>
 </action>
 </package>
 </struts>

Countr.java

 package b;

 import java.util.ArrayList;
 import com.opensymphony.xwork2.ActionSupport;

 public class Countr extends ActionSupport/*class Countr*/
 {

 public ArrayList countrylist;
 String country;

 public  ArrayList getCountrylist()/*getting countrylist*/
 {
 return countrylist;
 }
 public void setCountrylist( ArrayList countrylist)/*setting countrylist*/
 {
 this.countrylist=countrylist;
 }
 public  String getCountry()/*getting country*/
 {
 return country;
 }
 public void setCountry( String country)/*setting country*/
 {
 this.country=country;
 }



 public String execute() 
 {
   countrylist = new ArrayList();/*creating the arraylist*/
   countrylist.add("1");
   countrylist.add("!");
   countrylist.add("1");
   return SUCCESS;

}

}

=======================

updatedesig.jsp

<%@page contentType="text/html" pageEncoding="UTF-8"%>
<%@taglib prefix="p" uri="/struts-tags" %>
<!DOCTYPE html>
<html>
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <title>JSP Page</title>
</head>
<body>
    <p:form action="count"method="post">
    <p:select name="country" list="countryList"  label="Select a country" />/*creating         list in jsp*/
    </p:form>
    <h1>Hello World!</h1>
</body>
</html>

struts.xml

<struts>

<package name="b" extends="struts-default">
<action name="count" class="b.Countr" >/*action class is Countr.java*/

  <result name="success">updatedesig.jsp</result>
 </action>
 </package>
 </struts>

Countr.java

 package b;

 import java.util.ArrayList;
 import com.opensymphony.xwork2.ActionSupport;

 public class Countr extends ActionSupport/*class Countr*/
 {

 public ArrayList countrylist;
 String country;

 public  ArrayList getCountrylist()/*getting countrylist*/
 {
 return countrylist;
 }
 public void setCountrylist( ArrayList countrylist)/*setting countrylist*/
 {
 this.countrylist=countrylist;
 }
 public  String getCountry()/*getting country*/
 {
 return country;
 }
 public void setCountry( String country)/*setting country*/
 {
 this.country=country;
 }



 public String execute() 
 {
   countrylist = new ArrayList();/*creating the arraylist*/
   countrylist.add("1");
   countrylist.add("!");
   countrylist.add("1");
   return SUCCESS;

}

}

========================

updatedesig.jsp

<%@page contentType="text/html" pageEncoding="UTF-8"%>
<%@taglib prefix="p" uri="/struts-tags" %>
<!DOCTYPE html>
<html>
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <title>JSP Page</title>
</head>
<body>
    <p:form action="count"method="post">
    <p:select name="country" list="countryList"  label="Select a country" />/*creating         list in jsp*/
    </p:form>
    <h1>Hello World!</h1>
</body>
</html>

struts.xml

<struts>

<package name="b" extends="struts-default">
<action name="count" class="b.Countr" >/*action class is Countr.java*/

  <result name="success">updatedesig.jsp</result>
 </action>
 </package>
 </struts>

Countr.java

 package b;

 import java.util.ArrayList;
 import com.opensymphony.xwork2.ActionSupport;

 public class Countr extends ActionSupport/*class Countr*/
 {

 public ArrayList countrylist;
 String country;

 public  ArrayList getCountrylist()/*getting countrylist*/
 {
 return countrylist;
 }
 public void setCountrylist( ArrayList countrylist)/*setting countrylist*/
 {
 this.countrylist=countrylist;
 }
 public  String getCountry()/*getting country*/
 {
 return country;
 }
 public void setCountry( String country)/*setting country*/
 {
 this.country=country;
 }



 public String execute() 
 {
   countrylist = new ArrayList();/*creating the arraylist*/
   countrylist.add("1");
   countrylist.add("!");
   countrylist.add("1");
   return SUCCESS;

}

}

============================

updatedesig.jsp

<%@page contentType="text/html" pageEncoding="UTF-8"%>
<%@taglib prefix="p" uri="/struts-tags" %>
<!DOCTYPE html>
<html>
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <title>JSP Page</title>
</head>
<body>
    <p:form action="count"method="post">
    <p:select name="country" list="countryList"  label="Select a country" />/*creating         list in jsp*/
    </p:form>
    <h1>Hello World!</h1>
</body>
</html>

struts.xml

<struts>

<package name="b" extends="struts-default">
<action name="count" class="b.Countr" >/*action class is Countr.java*/

  <result name="success">updatedesig.jsp</result>
 </action>
 </package>
 </struts>

Countr.java

 package b;

 import java.util.ArrayList;
 import com.opensymphony.xwork2.ActionSupport;

 public class Countr extends ActionSupport/*class Countr*/
 {

 public ArrayList countrylist;
 String country;

 public  ArrayList getCountrylist()/*getting countrylist*/
 {
 return countrylist;
 }
 public void setCountrylist( ArrayList countrylist)/*setting countrylist*/
 {
 this.countrylist=countrylist;
 }
 public  String getCountry()/*getting country*/
 {
 return country;
 }
 public void setCountry( String country)/*setting country*/
 {
 this.country=country;
 }



 public String execute() 
 {
   countrylist = new ArrayList();/*creating the arraylist*/
   countrylist.add("1");
   countrylist.add("!");
   countrylist.add("1");
   return SUCCESS;

}

}

/*Glassfish服务器日志的某些部分*/

WARNING: StandardWrapperValve[jsp]: PWC1406: Servlet.service() for servlet jsp threw exception
tag 'select', field 'list', name 'country': The requested list key 'countryList' could not be resolved as a collection/array/map/enumeration/iterator type. Example: people or people.{name} - [unknown location]
    at org.apache.struts2.components.Component.fieldError(Component.java:237)
    at org.apache.struts2.components.Component.findValue(Component.java:358)
    at org.apache.struts2.components.ListUIBean.evaluateExtraParams(ListUIBean.java:80)
    at org.apache.struts2.components.Select.evaluateExtraParams(Select.java:105)
    at org.apache.struts2.components.UIBean.evaluateParams(UIBean.java:856)
    at org.apache.struts2.components.UIBean.end(UIBean.java:510)
    at org.apache.struts2.views.jsp.ComponentTagSupport.doEndTag(ComponentTagSupport.java:42)
    at org.apache.jsp.updatedesig_jsp._jspx_meth_p_select_0(updatedesig_jsp.java:138)
    at org.apache.jsp.updatedesig_jsp._jspx_meth_p_form_0(updatedesig_jsp.java:107)
    at org.apache.jsp.updatedesig_jsp._jspService(updatedesig_jsp.java:68)
    at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:111)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:847)
    at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:403)
    at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:492)
    at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:378)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:847)
    at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1539)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:343)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:217)
    at org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:88)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:256)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:217)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:279)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
    at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:655)
    at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:595)
    at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:98)
    at com.sun.enterprise.web.PESessionLockingStandardPipeline.invoke(PESessionLockingStandardPipeline.java:91)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:162)
    at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:330)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:231)
    at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:174)
    at com.sun.grizzly.http.ProcessorTask.invokeAdapter(ProcessorTask.java:828)
    at com.sun.grizzly.http.ProcessorTask.doProcess(ProcessorTask.java:725)
    at com.sun.grizzly.http.ProcessorTask.process(ProcessorTask.java:1019)
    at com.sun.grizzly.http.DefaultProtocolFilter.execute(DefaultProtocolFilter.java:225)
    at com.sun.grizzly.DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:137)
    at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:104)
    at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:90)
    at com.sun.grizzly.http.HttpProtocolChain.execute(HttpProtocolChain.java:79)
    at com.sun.grizzly.ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:54)
    at com.sun.grizzly.SelectionKeyContextTask.call(SelectionKeyContextTask.java:59)
    at com.sun.grizzly.ContextTask.run(ContextTask.java:71)
    at com.sun.grizzly.util.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:532)
    at com.sun.grizzly.util.AbstractThreadPool$Worker.run(AbstractThreadPool.java:513)
    at java.lang.Thread.run(Thread.java:722)

最好提供系统抛出的错误/异常，否则对方很难说出任何事情。而且，没有人有那么多时间在系统中编写程序并查看错误

我的第一个可能的错误是

<p:select name="country" list="countryList"  label="Select a country" />

将选择更改为

  <p:select name="country" list="countrylist"  label="Select a country" />

JSP类

输出

你试过我下面的答案了吗？错误说明您试图检索的列表，框架无法在值堆栈中找到，我不是先生！！！在什么时候它会给你异常/错误？我已经在上面给出了异常我已经提到你必须处理一个appraoch。在你的JSP中，你提到列表为

countryList

，所以在这种情况下，你的操作应该有这个属性

countryList

，但是在你的情况下，你已经定义了属性的名称作为

countrylist

。当您的页面执行Struts2时，它正在寻找一个getter方法名

getCountryList（）

，而在您的例子中它被定义为

getCountryList（）

，因此框架无法找到所需的方法。请在您的操作类或JSP代码中找到正确的列表名。