学习使用泛型dao
(1)泛型接口GenericDaopublic interface GenericDao <T, ID extends Serializable>{ public T findById(ID id); T findById(ID id, boolean lock); public T load(ID id); List findAll(); List findByExample(T exampleInstance); T save(T entity); void update(T entity); void delete(T entity); }
(2)泛型接口实现GenericDaoImpl
public abstract class GenericDaoImpl <T, ID extends Serializable>extends HibernateDaoSupport implements GenericDao <T, ID>{ private Class persistentClass; public GenericDaoImpl() { this.persistentClass = (Class) ((ParameterizedType) getClass() .getGenericSuperclass()).getActualTypeArguments(); } public Class getPersistentClass() { return persistentClass; } @SuppressWarnings("unchecked") public T findById(ID id) {return (T) getHibernateTemplate().get(getPersistentClass(), id); } @SuppressWarnings("unchecked") public T load(ID id){T t = (T)getHibernateTemplate().load(getPersistentClass(), id);return t; }@SuppressWarnings("unchecked") public T findById(ID id, boolean lock) { T entity; if (lock) entity = (T) getHibernateTemplate().load(getPersistentClass(), id, LockMode.UPGRADE); else entity = findById(id); return entity; } public List findAll() { return findByCriteria(); } @SuppressWarnings("unchecked") public List findByExample(T exampleInstance) { DetachedCriteria detachedCrit = DetachedCriteria .forClass(getPersistentClass()); Example example = Example.create(exampleInstance); detachedCrit.add(example); return getHibernateTemplate().findByCriteria(detachedCrit); } @SuppressWarnings("unchecked") public List findByExample(T exampleInstance, String[] excludeProperty) { DetachedCriteria detachedCrit = DetachedCriteria .forClass(getPersistentClass()); Example example = Example.create(exampleInstance); for (String exclude : excludeProperty) { example.excludeProperty(exclude); } detachedCrit.add(example); return getHibernateTemplate().findByCriteria(detachedCrit); } public T save(T entity) { getHibernateTemplate().saveOrUpdate(entity); return entity; } public void update(T entity){getHibernateTemplate().update(entity); }public void delete(T entity) { getHibernateTemplate().delete(entity); } @SuppressWarnings("unchecked") protected List findByCriteria(Criterion... criterion) { DetachedCriteria detachedCrit = DetachedCriteria .forClass(getPersistentClass()); for (Criterion c : criterion) { detachedCrit.add(c);} return getHibernateTemplate().findByCriteria(detachedCrit); } }
(3)CustomersDao
public interface CustomersDao extends GenericDao <Customers,Integer>{}
(4)CustomersDaoImpl
public class CustomersDaoImpl extends GenericDaoImpl <Customers,Integer> implements CustomersDao{}
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