java.lang.ClassCastException: java.lang.Character cannot be cast to java.lang.String

最新推荐文章于 2021-10-15 16:22:38 发布

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最新推荐文章于 2021-10-15 16:22:38 发布

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本文详细介绍了在使用Struts2进行开发时，遇到数组元素为单字符时出现的ClassCastException错误，并提供了三种解决方法。通过修改数组元素的表示方式，可以避免此类错误的发生，确保程序的正常运行。

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转载自：http://blog.youkuaiyun.com/yejin191258966/article/details/8038782

这个问题因为我在今天使用iterator迭代输出值得时候，发现使用单字符的

[plain] view plain copy print ?

<table border="1" width="300">
<s:iterator var="bb" value="{
'1','2','3','4','5'
}">
<tr>
<td><s:property value="bb"/></td>
</tr>
</s:iterator>

	<table border="1" width="300">	
	<s:iterator var="bb" value="{
		'1','2','3','4','5'
	}">
		<tr>
			<td><s:property value="bb"/></td>
		</tr>		
	</s:iterator>

java.lang.ClassCastException: java.lang.Character cannot be cast to java.lang.String
at org.apache.struts2.components.Property.start(Property.java:159)
at org.apache.struts2.views.jsp.ComponentTagSupport.doStartTag(ComponentTagSupport.java:53)
at org.apache.jsp.s_002diterator_002dlist_jsp._jspx_meth_s_005fproperty_005f0(s_002diterator_002dlist_jsp.java:173)
at org.apache.jsp.s_002diterator_002dlist_jsp._jspx_meth_s_005fiterator_005f0(s_002diterator_002dlist_jsp.java:142)
at org.apache.jsp.s_002diterator_002dlist_jsp._jspService(s_002diterator_002dlist_jsp.java:80)
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:386)
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.struts2.dispatcher.FilterDispatcher.doFilter(FilterDispatcher.java:426)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
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:859)
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:722)

如果我们写数组元素时使用的单字符比如：a、b、c、d、e、f、g这样的单字符系统会当做字符处理所以不能这样

解决的办法：

1、使用双引号，外层改成单引号

[plain] view plain copy print ?

<s:iterator var="bb" value='{
"1","2","3"
}'>
<tr>
<td><s:property value="bb"/></td>
</tr>
</s:iterator>

	<s:iterator var="bb" value='{
		"1","2","3"
	}'>
		<tr>
			<td><s:property value="bb"/></td>
		</tr>		
	</s:iterator>

2、在现实内容哪里value变量对象+#

[plain] view plain copy print ?

<s:iterator var="bb" value="{
'a','b'
}">
<tr>
<td><s:property value="#bb"/></td>
</tr>
</s:iterator>

	<s:iterator var="bb" value="{
		'a','b'
	}">
		<tr>
			<td><s:property value="#bb"/></td>
		</tr>		
	</s:iterator>

3、使用系统默认

[plain] view plain copy print ?

<s:iterator var="bb" value="{
'a','b'
}">
<tr>
<td><s:property/></td>
</tr>
</s:iterator>

<s:iterator var="bb" value="{
		'a','b'
	}">
		<tr>
			<td><s:property/></td>
		</tr>		
	</s:iterator>

参考网址：

http://blog.youkuaiyun.com/chch010520/article/details/7423143