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POWhy is Struts2 converting my string to a string array?
 

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  1. POWhy is Struts2 converting my string to a string array?
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    <p>I have a Struts 2 (JDK 1.7, Struts 2.2.1) application that contains a list of filtering criteria, stored as strings in a map.</p> <pre><code>Map&lt; String, String &gt; m_filters = new HashMap&lt; String, String &gt;(); public Map&lt; String, String &gt; getFilters() { return m_filters; } </code></pre> <p>I pass a URL formatted like this:</p> <p><a href="http://myserver.com/myapp/GenerateReport.action?reportID=Whatever&amp;filters.fromDate=0&amp;filters.toDate=2000000000&amp;filters.FcsType=piv_cardholder_3kp&amp;detailed=true">http://myserver.com/myapp/GenerateReport.action?reportID=Whatever&amp;filters.fromDate=0&amp;filters.toDate=2000000000&amp;filters.FcsType=piv_cardholder_3kp&amp;detailed=true</a></p> <p>Even though the Map has both key &amp; value types specified as String, attempting to get a value from this </p> <pre><code> Map&lt; String, String &gt; filters = getFilters(); String value = filters.get( "fromDate" ); </code></pre> <p>causes this exception to be thrown:</p> <p><code>java.lang.ClassCastException: [Ljava.lang.String; cannot be cast to java.lang.String</code></p> <p>I reproduced this in a unit test, and confirmed in a debugger that Struts 2 seems to be creating a String[1] instead of a String for each of the parameters. i.e. it is a length-1 string array with the only string being the expected value ("0" in this case).</p> <p><strong>My question is:</strong> Is this a bug in Struts2, or am I doing something incorrectly?</p> <p>If it is a bug, is there a known workaround?</p>
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    1. USShawn D.
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    1. COCan you try String value = (java.lang.String) filters.get( "fromDate" ); and run?
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      1. USHarish Raj
    2. COWell, the problem is the map contains String[] entries, not Strings, even though it is parameterized (sp?) with <String, String>, so an explicit cast would still cause the error.
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      1. USShawn D.
    3. CO+1 btw because this was interesting I'm not certain the struts2 behaviour in this case is the most sensible. It is true you should be following conventions but it is also true that what you are experiencing isn't intuitive.
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      1. USQuaternion
 

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