Go语言视频零基础入门到精通

javalearner

public interface GenericDao<T> {
  void create(T entity);
  void delete(T entity);
  void update(T entity);
  
  T findById(Serializable oid);
  List<T> findAll();
  PageModel<T> findByPager(int pageNo, int pageSize);
} public class GenericDaoImpl<T> implements GenericDao<T> {
  
  private Class<T> entityClass;
  
  private String entityName;
  
  @SuppressWarnings("unchecked")
  public GenericDaoImpl(){
   //通过反射获取泛型的参数类型信息
   Type type = this.getClass().getGenericSuperclass();
   ParameterizedType pt = (ParameterizedType)type;
   
   Type argType = pt.getActualTypeArguments()[0];
   
   entityClass = (Class<T>)argType;
   
   this.entityName = entityClass.getName();
  }
   @Override
  public void create(T entity) {
   HibernateUtil.getSession().save(entity);
  } @Override
  public void delete(T entity) {
   HibernateUtil.getSession().delete(entity);
  } @SuppressWarnings("unchecked")
  @Override
  public List<T> findAll() {
//  return HibernateUtil.getSession().createQuery("from " + entityName).list();
   return HibernateUtil.getSession()
        .createCriteria(entityClass)
        .list();
  } @SuppressWarnings("unchecked")
  @Override
  public T findById(Serializable oid) {
   return (T)HibernateUtil.getSession().load(entityClass, oid);
  } @SuppressWarnings("unchecked")
  @Override
  public PageModel<T> findByPager(int pageNo, int pageSize) {
   PageModel<T> pm = new PageModel<T>();
   
   //Integer temp = (Integer)HibernateUtil.getSession().createCriteria(entityClass).setProjection(Projections.rowCount()).uniqueResult();
   Long temp = (Long)HibernateUtil.getSession()
       .createQuery("select count(o) from " + entityName + " o")
       .uniqueResult();
   
   if(null != temp){
    pm.setRecordCount(temp.intValue());
    pm.setDatas(HibernateUtil.getSession()
      .createCriteria(entityClass)
      .setMaxResults(pageSize)
      .setFirstResult((pageNo - 1) * pageSize)
      .list());
   }
   
   return pm;
  } @SuppressWarnings("unchecked")
  @Override
  public void update(T entity) {
   HibernateUtil.getSession().update(entity);
  }
  
} 其他的类或是接口只需要extends