Upload | data | database ASP (Active Server Pages) is a very early Web application solution from Microsoft and a simpler programming environment that most developers of web sites are familiar with. With ASP, we can create powerful dynamic Web applications. Although the ASP is very powerful, but some of the functionality with pure ASP code can not be done, in order to ensure the development of more powerful Web applications, we can invoke the use of COM components.
In daily work, such as the development of a "commodity online marketing System" bar, in order to enable customers to understand the appearance of goods, that is, customers look at the text of the product at the same time in the text next to the image of the product to explain, so that customers can have a systematic understanding of the product, the promotion of goods has a great help. So when we develop the system, of course we need to add a picture processing module, how to upload pictures to the server (the picture can be placed in a folder on the Web server can also be placed in a SQL Server server) and how to let the uploaded pictures on the browser side display, this is a developer to consider the problem.
Upload pictures to the server there are several ways, you can use the file upload components can also use the pure ASP code to achieve. In the CSDN Web version of ASP often asked such a question "How to use ASP to upload the picture to the database", in order to facilitate the csdn need to understand this knowledge, this article will explain the use of ASP upload pictures of the practice and give the code, readers.
First look at the various objects and their syntax that are used in your program:
1) Request.BinaryRead () method
Use the Request.BinaryRead () method to get the submitted file data
Syntax
Varrevalue= Request.BinaryRead (number)
The variable Varrevalue return value holds the binary data read from the client;
Parameter number indicates the size of the binary data to be read from the client.
2) Response.BinaryWrite () method
Use the Response.BinaryWrite () method to get picture data from the database and display it in the client's browser.
Syntax
Response.BinaryWrite data
Parameter data is a binary packet to be written into the client browser.
3) AppendChunk method
The purpose of the AppendChunk method is to append binary data to a field or Parameter object.
Syntax
Object. AppendChunk data
Parameter data is the packet to append to the field or Parameter object.
4) GetChunk Method
The GetChunk method returns the contents of the binary data.
Syntax
Object. GetChunk (size)
The parameter size indicates the length of the binary data to be returned, which can be a long integer expression.
5) Request.TotalBytes method
The Request.TotalBytes method returns the number of bytes of data read from the client, which corresponds to the numbers mentioned above, and can be greater than or equal to the numbers value.
Syntax
Number= Request.TotalBytes
With a general understanding of some of the methods and how they are used, we then start designing the database and related code.
The first step: Database design (for example, Ms SQL Server7):
CREATE TABLE img--Creates a table for storing pictures, named img
(
ID int identity (1,1) not NULL,
IMG Image
)
Second Step: program writing, which omits the user input interface, here only gives very important two files namely Picture upload processing (processimg.asp) and display picture (showimg.asp) file.
1) processimg.asp File code:
〈%
Response.buffer=true
Imagesize=request.totalbytes ' Gets the total number of bytes submitted for the amount of data
Imagedata=request.binaryread (imagesize) ' saves data read from the client
' Optimized binary data read
BNCRLF=CHRB (&CHR) (10)
Divider=leftb (IMAGEDATA,CLNG (InstrB (ImageData, Bncrlf))-1)
DSTART=INSTRB (ImageData, bncrlf& Bncrlf) +4
DEND=INSTRB (dstart+1, ImageData, divider)-DStart
Mydata=midb (ImageData, DStart, DEnd)
' Create an object instance
Set imgconn=server.createobject ("ADODB. Connection ")
Strconn= "Driver={sql Server}; Server=servername; " & _
"UID=XXXX; Pwd=xxxx;database=databasename "
Imgconn.open strconn
Set rs= Server.CreateObject ("ADODB.") RecordSet ")
Sql= "Select * from img Where ID is null"
Rs.Open sql,imgconn,1,3
' Append Data to Database
Rs.addnew
Rs ("img"). AppendChunk MyData
Rs.update
' Close and Release objects
Rs.close
Imgconn.close
Set rs=nothing
Set imgconn=nothing
%〉
2) showimg.asp File code:
〈%
Response.Expires = 0
Response.buffer=true
Response.Clear
' Create an object instance
Set imgconn=server.createobject ("ADODB. Connection ")
Strconn= "Driver={sql Server}; Server=servername; " & _
"UID=XXXX; Pwd=xxxx;database=databasename "
Imgconn.open strconn
Set rs= Server.CreateObject ("ADODB.") RecordSet ")
Sql= "Select img from img Where id=1" Here the ID can be obtained using request ("id")
Rs.Open sql,imgconn,1,1
Response.contenttype= "image/*"
Response.BinaryWrite Rs. ("img"). GetChunk (7500000)
' Close and Release objects
Rs.close
Imgconn.close
Set rs=nothing
Set imgconn=nothing
%〉
At this point, this article on how to use ASP upload pictures of the principle and examples are finished, there is nothing wrong to please correct me, thank you! At the same time hope that this article can really help the users need to provide substantive help.
