学习使用泛型dao

log_cd

(1)泛型接口GenericDao


public 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()[0];    }    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{}