ASP.NET 实现通过URL 获取远程的图片或者文件方法

<FROM Java Database Best Practise>

在各tier之间传递value的时候，不是传递的BO，也没有自行开发Data Object，而是使用所谓Mememto的Pattern，具体用HashMap作为Data Object。而在Data Object中的属性存取上，利用在BO中定义的Constant Name作为属性名，以避免拼写错误并方便编程。
Eg. BO Emplyee 及 DAO EmployeeDAO的写法。

Employee.java


package ee.mememto;




import java.util.*;






public class Employee ...{




public static final String EMP_ID = "emp_id";


public static final String EMP_NAME = "emp_name";


public static final String EMAIL = "email";


public static final String IS_ACTIVE = "is_active";


public static final String CREATED = "created";




private Long empId = null;


private String empName = null;


private String email = null;


private Boolean isActive = null;


private Date created = null;






public static Employee create(HashMap data)...{


Employee emp = null;


Long id = new Long(1L);


data.put(Employee.EMP_ID, id);


emp = new Employee(id,data);


return emp;


}






private Employee(Long id,HashMap data)...{


empId = id;


load(data);


}






private void load(HashMap data)...{


empName = (String)data.get(Employee.EMP_NAME);


email = (String)data.get(Employee.EMAIL);


isActive = (Boolean)data.get(Employee.IS_ACTIVE);


created = (Date)data.get(Employee.CREATED);


}


}





EmployeeDAO.java


package ee.mememto;




import java.util.*;






public class EmployeeDAO ...{






public static HashMap getEmployee(long id)...{


HashMap data = new HashMap();




return data;


}






public static void create(HashMap data)...{




}






public static void save(HashMap data)...{




}






public static void remove(HashMap data)...{




}


}





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