要在Alfresco中创建子文件夹并生成公开共享链接，您可以按照以下步骤进行操作：

1. 连接到Alfresco仓库：

String url = "http://localhost:8080/alfresco/service/api";
String username = "admin";
String password = "admin";
AuthenticationUtils.startSession(username, password);
RepositoryServiceSoapBindingStub repositoryService = WebServiceFactory.getRepositoryService(url);

2. 创建父文件夹：

String parentFolderNodeId = "-root-";
String parentFolderName = "Parent Folder";
String parentFolderDescription = "This is the parent folder";
String parentFolderType = "{http://www.alfresco.org/model/content/1.0}folder";
ParentReference parentReference = new ParentReference(STORE, parentFolderNodeId, null, ASSOC_CONTAINS, null);
NamedValue[] properties = new NamedValue[3];
properties[0] = Utils.createNamedValue("cm:name", parentFolderName);
properties[1] = Utils.createNamedValue("cm:description", parentFolderDescription);
properties[2] = Utils.createNamedValue("cm:folderType", parentFolderType);
CMLCreate create = new CMLCreate("1", parentReference, null, null, null, TYPE_FOLDER, properties);
CML cml = new CML();
cml.setCreate(new CMLCreate[] { create });
UpdateResult[] results = repositoryService.update(cml);
String parentFolderNodeId = results[0].getDestination().getPath();

3. 创建子文件夹：

String subFolderName = "Sub Folder";
String subFolderDescription = "This is the sub folder";
String subFolderType = "{http://www.alfresco.org/model/content/1.0}folder";
ParentReference subFolderParentReference = new ParentReference(STORE, parentFolderNodeId, null, ASSOC_CONTAINS, null);
NamedValue[] subFolderProperties = new NamedValue[3];
subFolderProperties[0] = Utils.createNamedValue("cm:name", subFolderName);
subFolderProperties[1] = Utils.createNamedValue("cm:description", subFolderDescription);
subFolderProperties[2] = Utils.createNamedValue("cm:folderType", subFolderType);
CMLCreate subFolderCreate = new CMLCreate("1", subFolderParentReference, null, null, null, TYPE_FOLDER, subFolderProperties);
CML subFolderCml = new CML();
subFolderCml.setCreate(new CMLCreate[] { subFolderCreate });
UpdateResult[] subFolderResults = repositoryService.update(subFolderCml);
String subFolderNodeId = subFolderResults[0].getDestination().getPath();

4. 生成公开共享链接：

String shareUrl = repositoryService.getShareUrl(subFolderNodeId).getShareUrl();

请注意，上述示例代码是Java代码，并且假定您已经设置了Alfresco的Web服务接口。您需要使用Alfresco的Java API或其他适当的开发工具来实现这些代码。