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[英]How to create an entity relationship between an abstract class and a concrete class in a java spring-boot app?
[英]How to create an abstract class that will handle basic CRUD with GreenDAO for any Entity model
我想創建一個抽象類,該抽象類將調用Dao插入任何實體對象,以避免在實現IRepository
每個類中編寫重復的代碼,
public abstract class DBStore<T> implements IRepository {
DaoMaster daoMaster;
Class<T> entityClass;
public DBStore(DaoMaster daoMaster, Class<T> entityClass) {
this.daoMaster = daoMaster;
this.entityClass = entityClass;
}
@Override
public void add(Entity entity) {
DaoSession session = this.daoMaster.newSession();
AbstractDao<?, ?> dao = session.getDao(this.entityClass);
dao.insert(entity); // cannot pass entity as parameter because insert() expects capture<?>
}
// Other CRUD methods
}
我不明白應該使用什么語法來指定變量entity
是insert()
期望的。
好的,我通過指定DBStore<T extends Entity> implements IRepository<T>
並將AbstractDao<?, ?>
為AbstractDao<T, Long>
來使其工作
這是完整的代碼:
public abstract class DBStore<T extends Entity> implements IRepository<T> {
DaoMaster daoMaster;
Class<T> entityClass;
public DBStore(DaoMaster daoMaster, Class<T> entityClass) {
this.daoMaster = daoMaster;
this.entityClass = entityClass;
}
@Override
public void add(T entity) {
this.getSession().insert(entity);
}
@Override
public T getById(long id) {
AbstractDao<T, Long> dao = this.getDao();
return dao.load(id);
}
//other methods
protected AbstractDao<T, Long> getDao(){
DaoSession session = this.daoMaster.newSession();
return (AbstractDao<T, Long>) session.getDao(this.entityClass);
}
protected DaoSession getSession(){
return this.daoMaster.newSession();
}
}
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