tailieunhanh - Java Persistence with Hibernate phần 3

đồng bộ với nhà nước của các widget như (hoặc thao tác) của người sử dụng. JSF là một bài thuyết trình hướng sự kiệnhiệu quả sản xuất tương đương với một bản đồ thành kê 5,5 loại bản đồ tuỳ chỉnh cho số lượng tiền tệ trong các lược đồ cơ sở dữ liệu mới | Alternative entity representation 141 MAP No Java classes are required entities are represented in the Java application with HashMaps. This mode allows quick prototyping of fully dynamic applications. DOM4J NoJava classes are required entities are represented as XML elements based on the dom4j API. This mode is especially useful for exporting or importing data or for rendering and transforming data through XSLT processing. There are two reasons why you may want to skip the next section and come back later First a static domain model implementation with POJOs is the common case and dynamic or XML representation are features you may not need right now. Second we re going to present some mappings queries and other operations that you may not have seen so far not even with the default POJO entity mode. However if you feel confident enough with Hibernate read on. Let s start with the MAP mode and explore how a Hibernate application can be fully dynamically typed. Creating dynamic applications A dynamic domain model is a model that is dynamically typed. For example instead of a Java class that represents an auction item you work with a bunch of values in a Java Map. Each attribute of an auction item is represented by a key the name of the attribute and its value. Mapping entity names First you need to enable this strategy by naming your business entities. In a Hibernate XML mapping file you use the entity-name attribute hibernate-mapping class entity-name ItemEntity table ITEM_ENTITY id name id type long column ITEM_ID generator class native id property name initialPrice type big_decimal column INIT_PRICE property name description type string column DESCRIPTION many-to-one name seller entity-name UserEntity column USER_ID 142 CHAPTER 3 Domain models and metadata class class entity-name UserEntity table USER_ENTITY id name id type long column USER_ID generator class native id property name username type string column USERNAME bag name itemsForSale inverse true .