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今天用struts2的if标签作一个判断，死活到不了if里面，代码如下： <s:if test="namePinYin == 'a'">hello</s:if> 页面也不报错，而且也测试了namePinYin的确等于a 后来发现服务器报了个NumberFormatException，信息如下： Caught an exception while evaluating expression 'namePinYin == 'a'' against value stack java.lang.NumberFormatException: For input string: "a" at sun.misc.FloatingDecimal.readJavaFormatString(FloatingDecimal.java:1224) google了一下，发现问题其实很简单，namePinYin是个字符串，test的时候需要这样写： <s:if test='namePinYin == "a"'>hello</s:if> 照这样看，单引号可能会用于比较数字类型，详细可以查看一下官方的faq: http://struts.apache.org/2.x/docs/why-wont-the-if-tag-evaluate-a-one-char-string.html <s:if test="aStringProperty == 'A'"> Why doesn't this work when myString is equal to A? </s:if> <s:if test='aStringProperty == "A"'> This works! </s:if>转载于:https://www.cnblogs.com/cuizhf/archive/2012/09/17/2688362.html
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