title: how to use struts2 tag to traversal a Map<Object,String> in jsp
body: <p>How to use Struts2 tag to traversal a <code>Map&lt;Course,String&gt;</code> in JSP.
  <code>Course</code> is a class. It has three attributes. They are <code>String coursename</code>, <code>int courseid</code>, <code>String courseType</code>. I use Struts2 in my project. The Action returns the <code>Map&lt;Course,String&gt;</code> to JSP.
  And I use </p>
  
  <pre><code>&lt;s:iterator value="cmap" status="st"&gt;
    &lt;tr&gt;&lt;td&gt;
      &lt;s:iterator value='key'&gt;&lt;s:property value="key.coursename"/&gt;&lt;/s:iterator&gt; &lt;/td&gt;
     &lt;td&gt;&lt;s:property value='value'&gt;&lt;/s:property&gt;&lt;/td&gt;&lt;/tr&gt;
  &lt;/s:iterator&gt;
  </code></pre>
  
  <p>It can print the right String value in JSP. But it cannot print the Course Type data!
  How to solve it? I am a novice.</p>