用内部类定义java常量

public class DataServiceConstant {

	/**
	 * 数据推送类型
	 * 	 *
	 */
	public static final class PushDataType{
		/**
		 * 附件
		 */
		public static final String DATA_FILE = "file";
		/**
		 * 列表
		 */
		public static final String DATA_LSIT = "list";

		/**
		 * 详情
		 * 
		 */
		public static final String DATA_DETAIL = "detail";
	}
}