/**
* 对所有properties的key排序并分组。
*
* @param level 分组的级别
* @return 分组列表
*/
private List[] getSortedKeys(Map props, int level) {
List keys = new ArrayList(props.keySet());
Collections.sort(keys);
List groups = new ArrayList();
List group = null;
String prefix = null;
for (Iterator i = keys.iterator(); i.hasNext(); ) {
String key = (String) i.next();
String[] parts = StringUtil.split(key, ".");
StringBuffer buffer = new StringBuffer();
for (int j = 0; j < parts.length - 1 && j < level; j++) {
if (buffer.length() > 0) {
buffer.append('.');
}
buffer.append(parts[j]);
}
String keyPrefix = buffer.toString();
if (!keyPrefix.equals(prefix)) {
if (group != null) {
groups.add(group);
}
prefix = keyPrefix;
group = new ArrayList();
}
group.add(key);
}
if (group != null && group.size() > 0) {
groups.add(group);
}
return (List[]) groups.toArray(new List[groups.size()]);
}