技術標籤：hibernate hql查詢個別欄位對映到實體類

在頁面上建立表模型新增修改欄位。涉及到動態生成表結構，動態生成模型實體類動態查詢表字段等等，經過調研發現hibernate在這方面是很方便的，呼叫內建API就能完成系列操作，下面貼出核心程式碼：

/** * @author cjbi */public class DynamicDdlTest {    @Autowired    private EntityManagerFactory entityManagerFactory;/** * 執行期的持久化實體沒有必要一定表示為像POJO類或JavaBean物件那樣的形式。 * Hibernate也支援動態模型在執行期使用Map)和象DOM4J的樹模型那樣的實體表示。 * 使用這種方法，你不用寫持久化類，只寫對映檔案就行了。**/    public static final String XML_MAPPING = "<?xml version="1.0" encoding="UTF-8"?>" +            " +            "        "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">" +            "" +            "    " +            "        " +            "            " +            "        " +            "        " +            "        " +            "        " +            "        " +            "        " +            "    " +            "";    @Test    public void testDynamicDdl() {        SessionFactory sessionFactory =  entityManagerFactory.unwrap(SessionFactory.class);        StandardServiceRegistry serviceRegistry = sessionFactory.getSessionFactoryOptions().getServiceRegistry();        MetadataSources metadataSources = new MetadataSources(serviceRegistry);        sessionFactory.getSessionFactoryOptions();        //讀取對映檔案        metadataSources.addInputStream(new ByteArrayInputStream(XML_MAPPING.getBytes()));        Metadata metadata = metadataSources.buildMetadata();        //建立資料庫Schema,如果不存在就建立表,存在就更新欄位,不會影響已有資料        SchemaExport schemaExport = new SchemaExport();        schemaExport.createOnly(EnumSet.of(TargetType.DATABASE), metadata);                Metadata metadata = metadataSources.buildMetadata();        //建立會話工廠        SessionFactory newSessionFactory = metadata.buildSessionFactory();        //儲存物件        Session newSession = newSessionFactory.openSession();        for (int i = 0; i < 100; i++) {            Map student = new HashMap<>();            student.put("username", "張三" + i);            student.put("password", "adsfwr" + i);            student.put("sex", i % 2 == 0 ? "male" : "female");            student.put("age", i);            student.put("birthday", new Date());            newSession.save("Student", student);        }        //查詢所有物件        Query query = newSession.createQuery("from Student");        List list = query.getResultList();        System.out.println("resultList: " + list);        //關閉會話        newSession.close();    }}