Umesh 我将向您展示我们如何实现此功能
界面
public interface Repository<INSTANCE_CLASS, PRIMARY_KEY_CLASS> {
void add(INSTANCE_CLASS instance);
void merge(INSTANCE_CLASS instance);
void remove(PRIMARY_KEY_CLASS id);
INSTANCE_CLASS findById(PRIMARY_KEY_CLASS id);
INSTANCE_CLASS findById(PRIMARY_KEY_CLASS id, Class fetchingStrategy, Object... args);
List<INSTANCE_CLASS> findAll();
List<INSTANCE_CLASS> findAll(Class fetchingStrategy, Object... args);
List<INSTANCE_CLASS> findAll(int pageNumber, int pageSize);
List<INSTANCE_CLASS> findAll(int pageNumber, int pageSize, Class fetchingStrategy, Object... args);
List<INSTANCE_CLASS> findAllByCriteria(Criteria criteria);
List<INSTANCE_CLASS> findAllByCriteria(Criteria criteria, Class fetchingStrategy, Object... args);
List<INSTANCE_CLASS> findAllByCriteria(int pageNumber, int pageSize, Criteria criteria);
List<INSTANCE_CLASS> findAllByCriteria(int pageNumber, int pageSize, Criteria criteria, Class fetchingStrategy, Object... args);
}
因为您通常不需要上面显示的所有方法,所以我们创建一个抽象类目的是作为一个虚拟实现
public abstract class AbstractRepository<INSTANCE_CLASS, PRIMARY_KEY_CLASS> implements Repository<INSTANCE_CLASS, PRIMARY_KEY_CLASS> {
public void add(INSTANCE_CLASS instance) {
throw new UnsupportedOperationException("Not supported yet.");
}
public void merge(INSTANCE_CLASS instance) {
throw new UnsupportedOperationException("Not supported yet.");
}
public void remove(PRIMARY_KEY_CLASS id) {
throw new UnsupportedOperationException("Not supported yet.");
}
public INSTANCE_CLASS findById(PRIMARY_KEY_CLASS id) {
throw new UnsupportedOperationException("Not supported yet.");
}
public INSTANCE_CLASS findById(PRIMARY_KEY_CLASS id, Class fetchingStrategy, Object... args) {
throw new UnsupportedOperationException("Not supported yet.");
}
public List<INSTANCE_CLASS> findAll() {
throw new UnsupportedOperationException("Not supported yet.");
}
public List<INSTANCE_CLASS> findAll(Class fetchingStrategy, Object... args) {
throw new UnsupportedOperationException("Not supported yet.");
}
public List<INSTANCE_CLASS> findAll(int pageNumber, int pageSize) {
throw new UnsupportedOperationException("Not supported yet.");
}
public List<INSTANCE_CLASS> findAll(int pageNumber, int pageSize, Class fetchingStrategy, Object... args) {
throw new UnsupportedOperationException("Not supported yet.");
}
public List<INSTANCE_CLASS> findAllByCriteria(Criteria criteria) {
throw new UnsupportedOperationException("Not supported yet.");
}
public List<INSTANCE_CLASS> findAllByCriteria(Criteria criteria, Class fetchingStrategy, Object... args) {
throw new UnsupportedOperationException("Not supported yet.");
}
public List<INSTANCE_CLASS> findAllByCriteria(int pageNumber, int pageSize, Criteria criteria) {
throw new UnsupportedOperationException("Not supported yet.");
}
public List<INSTANCE_CLASS> findAllByCriteria(int pageNumber, int pageSize, Criteria criteria, Class fetchingStrategy, Object... args) {
throw new UnsupportedOperationException("Not supported yet.");
}
}
现在,例如,如果您想要一个只需要添加方法的存储库,您可以使用
public class PersonRepository extends AbstractRepository<Person, Integer> {
public void add(Person instance) {
/**
* person implmentatiuon goes here
*/
}
}
如果其他开发人员尝试访问除添加方法之外的方法,他或她将得到不支持的操作异常
标准只是一个标记接口.
public interface Criteria {}
一些方法的目的是定义一个参数类fetchingStrategy是匹配外部化的命名查询。这样,我就避免了容易出错的手工编码字符串。例如,JSR-303 bean 验证使用此方法来验证groups的属性。看here http://download.oracle.com/javaee/6/api/javax/validation/Validator.html#validate%28T,%20java.lang.Class...%29
public class Person {
public static interface PERSON_WITH_ADDRESS {}
}
externalize命名查询如下所示
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
<query name="PERSON_WITH_ADDRESS">
<![CDATA[
from
Person p
left join fetch
p.address
]]>
</query>
</hibernate-mapping>
所以当我想检索所有有地址的人时,我打电话
PersonRepository<Person, Integer> respository ...
List<Person> personList = repository.findAll(PERSON_WITH_ADDRESS.class);
findAll 可以写成
public class PersonRepository extends AbstractRepository<Person, Integer> {
List<Person> findAll(Class fetchingStrategy, Object... args) {
if(fetchingStrategy.isAssignableFrom(PERSON_WITH_ADDRESS.class)) {
sessionFactory.getCurrentSession()
.getNamedQuery(fetchingStrategy.getSimpleName())
.list();
}
throw new UnsupportedOperationException("Not supported yet.");
}
}