How to create folder tree as a/b/c/d?

[rvbb]

I tried to create a folder tree such as a/b/c/d, but Sardine always don't allow: 405 or 409 error will be replied.

public boolean createFolder(String folderName) throws Exception {
try {
this.sardine.createDirectory(this.baseUrl + "/" + folderName + "/");
return true;
} catch (Exception e) {
e.printStackTrace();
return false;
}
}
public boolean createFolderTree(String folderTree, String parentFolder) throws Exception {
try {
if(Util.empty(folderTree) || folderTree.indexOf("/") < 0) {
return true;
}
String parentFirst = folderTree.substring(0, folderTree.indexOf("/"));
String subFolderTree = folderTree.substring(folderTree.indexOf("/") + 1);
if(!Util.empty(parentFirst)) {
if(!Util.empty(parentFolder)) {
createFolder(parentFolder + "/" + parentFirst);
}else {
createFolder(parentFirst);
}
}
createFolderTree(subFolderTree, parentFirst);
return true;
} catch (Exception e) {
e.printStackTrace();
return false;
}
}
`

Plz support.