2018-03-01web开发中业务层和dao层的耦合问题

在实际开发过程中,为了防止耦合,实现一个dao层方法接口,业务层,从一个工厂间接获得dao层对象,工厂读取.properties文件,避免直接创建dao层对象,dao层只需实现接口方法即可

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• .properties

CustomerDao=com.chen.customers.dao.impl.CustomerDaoImpl

• CustomerDao接口

public interface CustomerDao {

    //完成客户信息的添加
    void insertCustomer(Customer bean);

}

• dao层的CustomerDao接口实现类

public class CustomerDaoImpl implements CustomerDao  {
    
    
    
    //完成客户信息的添加
    /* (non-Javadoc)
     * @see com.chen.customers.dao.CustomerDao#insertCustomer(com.chen.customers.domain.Customer)
     */
    @Override
    public void insertCustomer(Customer bean) {
        
        QueryRunner runner = new QueryRunner(JdbcUtils.getDataSource());
        
        String sql = "insert into customers values(?,?,?,?,?,?,?,?,?)";
        Object[]  params = {genereateID(),bean.getName(),bean.getGender()
                ,bean.getBirthday(),bean.getEmail(),
                bean.getCellphone(),bean.getPreference(),
                bean.getType(),bean.getDescription()};
        
        try {
            runner.update(sql,params);
        } catch (SQLException e) {
            
            throw new RuntimeException(e);

        }
        
        
    }
}

• DaoFactory工厂类

/*
*这是一个工厂类
*
*/
public class DaoFactory {
    
    public DaoFactory() {
        // TODO Auto-generated constructor stub
    }
    
    //创建一个工厂的实例
    private  static DaoFactory instance =  new DaoFactory();
    
    public static DaoFactory getInstance() {
        
        return instance;
        
    }
    
    //用于返回传进来的一个实例对象出来
    //泛型,传进来一个类的字节码
    public  T createDao(Class t) {
        
        //Teacher.class
        String simpleName = t.getSimpleName();//Teacher
        
        //读取一个配置文件: CustomerDao=com.chen.customers.dao.impl.CustomerDaoImpl
        String clazzName = ResourceBundle.getBundle("dao").getString(simpleName);//com.chen.customers.dao.impl.CustomerDaoImpl
        
        try {
            return (T)Class.forName(clazzName).newInstance();
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
            return null;
        }
        
    }

}