struts2 ognl静态方法调用无效

public static String clobToString(Clob clob) throws SQLException, IOException {
String reString = "";
Reader is = clob.getCharacterStream();// 得到流
BufferedReader br = new BufferedReader(is);
String s = br.readLine();
StringBuffer sb = new StringBuffer();
while (s != null) {// 执行循环将字符串全部取出付值给StringBuffer由StringBuffer转成STRING
sb.append(s);
s = br.readLine();
}
reString = sb.toString();
System.err.println(reString);
return reString;
}

<s:property value="@edu.dzu.util.StringDeal@clobToString( newsBean.contents )" escape="false" />

<constant name="struts.ognl.allowStaticMethodAccess" value="true" />