善用Generic可以減少相當多的程式碼,基本上一定會用的是在DAO及Service中
BaseDao
public interface BaseDao<T, ID extends Serializable> {
public T get(ID id);
public void save(T entity);
public void delete(T entity);
public List findAll(String[] ascProperties, String[] descProperties);
public List findByExample(T entity, String[] ascProperties, String[] descProperties);
public int countByExample(T entity);
}
HibernateBaseDao
public abstract class HibernatetBaseDao<T, ID extends Serializable> extends
HibernateDaoSupport {
private Class domainClass;
public HibernatetBaseDao() {
this.domainClass = (Class) ((ParameterizedType) getClass()
.getGenericSuperclass()).getActualTypeArguments()[0];
}
public void delete(T entity) {
this.getHibernateTemplate().delete(entity);
}
@SuppressWarnings("unchecked")
public List findAll(String[] ascProperties, String[] descProperties) {
Criteria criteria = this.getSession().createCriteria(this.domainClass);
this.addOrderToCriteria(criteria, ascProperties, descProperties);
return criteria.list();
}
@SuppressWarnings("unchecked")
public List findByExample(T entity, String[] ascProperties,
String[] descProperties) {
Criteria criteria = this.getSession().createCriteria(this.domainClass);
Example example = Example.create(entity);
criteria.add(example);
this.addOrderToCriteria(criteria, ascProperties, descProperties);
return criteria.list();
}
@SuppressWarnings("unchecked")
public T get(ID id) {
return (T) this.getHibernateTemplate().get(this.domainClass, id);
}
public void save(T entity) {
this.getHibernateTemplate().saveOrUpdate(entity);
}
public int countByExample(T entity) {
Criteria criteria = this.getSession().createCriteria(this.domainClass);
if (null != entity) {
Example example = Example.create(entity);
criteria.add(example);
}
return ((Integer) criteria.setProjection(Projections.rowCount()).list()
.iterator().next()).intValue();
}
protected void addOrderToCriteria(Criteria criteria,
String[] ascProperties, String[] descProperties) {
if (null != ascProperties && 0 < ascProperties.length) {
for (String property : ascProperties) {
criteria.addOrder(Order.asc(property));
}
}
if (null != descProperties && 0 < descProperties.length) {
for (String property : descProperties) {
criteria.addOrder(Order.desc(property));
}
}
}
public Class getDomainClass() {
return domainClass;
}
public void setDomainClass(Class domainClass) {
this.domainClass = domainClass;
}
}
BaseManager
public interface BaseManager<T, ID extends Serializable> {
public T get(ID id);
public void save(T entity);
public void delete(T entity);
public void delete(ID id);
public List findAll();
public List findAll(String[] ascProperties, String[] descProperties);
public List findByExample(T entity);
public List findByExample(T entity, String[] ascProperties, String[] descProperties);
public int count();
public int countByExample(T entity);
}
AbstractBaseManager
public abstract class AbstractBaseManager<T, ID extends Serializable, DAO extends BaseDao<T, ID>> {
private DAO baseDao;
public T get(ID id) {
return baseDao.get(id);
}
public void save(T entity) {
this.baseDao.save(entity);
}
public void delete(T entity) {
this.baseDao.delete(entity);
}
public void delete(ID id) {
this.baseDao.delete(this.get(id));
}
public List findAll() {
return this.findAll(new String[0], new String[0]);
}
public List findAll(String[] ascProperties, String[] descProperties) {
return this.baseDao.findAll(ascProperties, descProperties);
}
public List findByExample(T entity) {
return this.findByExample(entity, new String[0], new String[0]);
}
public List findByExample(T entity, String[] ascProperties,
String[] descProperties) {
return this.findByExample(entity, ascProperties, descProperties);
}
public int count() {
return this.countByExample(null);
}
public int countByExample(T entity) {
return this.baseDao.countByExample(entity);
}
public DAO getBaseDao() {
return baseDao;
}
public void setBaseDao(DAO baseDao) {
this.baseDao = baseDao;
}
}
這樣每新增一個Domain Class要做基本的CRUD時,僅需要這樣宣告
public interface MasterDao extends BaseDao<Master, String> {
}
public class MasterDaoImpl extends HibernatetBaseDao<Master, String> implements MasterDao {
public MasterDaoImpl() {
super();
}
}
public interface MasterManager extends BaseManager<Master, String> {
}
public class MasterManagerImpl extends AbstractBaseManager<Master, String, MasterDao> implements
MasterManager {
}
雖然Service與DAO間Method重覆性太高,但是維持了架構的一致性,雖然不是很滿意,還好目前使用Generic減少了重覆的Code,還算是可以接受.
