Spring 基类抽取

深碍√TFBOYSˉ_ 2022-04-06 06:24 200阅读 0赞

一、基类抽取

有时候我们为了代码结构更加的简化，能够减少代码的重复率，做到DRY原则，我们通常抽取部分公共代码出来

二、原始代码

public interface IEmployeeDao  {
        void save(Employee employee);
    
        void update(Employee employee);
    
        void delete(Long t);
    
        Employee get(Long id);
    
        List<Employee> listAll();
    }
    
    
    @Repository("employeeDao")
    public class EmployeeDaoImpl implements IEmployeeDao{
    
        @Setter
        private SessionFactory sessionFactory;
    
    
    
        @Override
        public void save(Employee dmployee) {
            Session session = sessionFactory.getCurrentSession();
            session.save(dmployee);
        }
    
        @Override
        public void update(Employee dmployee) {
            Session session = sessionFactory.getCurrentSession();
            session.update(dmployee);
        }
    
        @Override
        public void delete(Employee dmployee) {
            Session session = sessionFactory.getCurrentSession();
            session.delete(dmployee);
        }
    
        @Override
        public Employee get(Long id) {
              Session session = sessionFactory.getCurrentSession();
            return (Employee) session.get(Employee.class,id);
        }
    
        @Override
        public List<Employee> listAll() {
            Session session = sessionFactory.getCurrentSession();
           return session.createCriteria(Employee.class).list();
        }
    }

**三、简单抽取**

基类：

/**
     * 泛型dao接口：所有dao接口的父类
     * @param <T>
     */
    public interface IGenericDao<T> {
        void save(T t);
    
        void update(T t);
    
        void delete(Long t);
    
        T get(Long id);
    
        List<T> listAll();
    }
    
    abstract public  class GenericDaoImpl<T> implements IGenericDao<T> {
     
     
          // 获取真实的字节码类型
          public abstract Class<T> getTargetType();
    
    
        @Setter
        private SessionFactory sessionFactory;
    
    
        @Override
        public void save(T t) {
            Session session = sessionFactory.getCurrentSession();
            session.save(t);
        }
    
        @Override
        public void update(T t) {
            Session session = sessionFactory.getCurrentSession();
            session.update(t);
        }
    
        @Override
        public void delete(Long t) {
            Session session = sessionFactory.getCurrentSession();
           Object obj =  session.get(getTargetType(),t);
            session.delete(obj);
        }
    
        @Override
        public T get(Long id) {
            Session session = sessionFactory.getCurrentSession();
            return (T) session.get(getTargetType(),id);
        }
    
        @Override
        public List<T> listAll() {
            Session session = sessionFactory.getCurrentSession();
            return session.createCriteria(getTargetType()).list();
        }
    }

具体业务类：

// 此处写非公共部分，针对于不同的业务
    public interface IEmployeeDao extends IGenericDao<Employee> {
    
    }
    @Repository("employeeDao")
    public class EmployeeDaoImpl extends GenericDaoImpl<Employee> implements IEmployeeDao {
    
        @Override
        public Class<Employee> getTargetType() {
            return Employee.class;
        }
    }

**四、获得泛型实体类的过程示例**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L20wXzM4MDY4ODEy_size_16_color_FFFFFF_t_70][]

**API示例**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L20wXzM4MDY4ODEy_size_16_color_FFFFFF_t_70 1][]

**五、抽取结果**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L20wXzM4MDY4ODEy_size_16_color_FFFFFF_t_70 2][]

![20181208183203778.png][]

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[20181208183203778.png]: /images/20220406/0ff129ce976349bb97a5ab715de696b2.png