在現在很多的應用中，數據庫會經常要存取一些大容量的數據，典型的代表：Blob,LongRaw
本文主要介紹這兩種類型存取圖形的操作(jsp頁面的訪問)。
一 Blob
建立Table:
CREATE TABLE PHOTO
(
PHOTO_NO VARCHAR2(1) NOT NULL,
IMAGE BLOB
) showimage.jsp
<%
/**//*
從Oracle數據庫中讀取Blob的類型,並且在jsp頁面中顯示出來
*/
%>
<%@ page contentType="text/html; charset=BIG5" %>
<%@ page import="java.io.*"%>
<%@ page import="java.sql.*, javax.sql.*" %>
<%@ page import="java.util.*"%>
<%@ page import="java.math.*"%>
<%
String photo_no = request.getParameter("photo_no");
//out.print(photo_no);
//Oracle連結
Class.forName("oracle.jdbc.driver.OracleDriver");
String url="jdbc:oracle:thin:@IP:1521:SID";
String userName="user";
String pwd="pwd";
Connection conn=DriverManager.getConnection(url,userName,pwd);
try
{
Statement stmt = conn.createStatement();
String sql = " SELECT * FROM PHOTO WHERE photo_no = "+ photo_no;
ResultSet rs = stmt.executeQuery(sql);
if (rs.next()) {
Blob b = rs.getBlob("image");
long size = b.length();
//out.print(size);
byte[] bs = b.getBytes(1, (int)size);
response.setContentType("image/jpeg");
OutputStream outs = response.getOutputStream();
outs.write(bs);
outs.flush();
rs.close();
}
else {
rs.close();
}
}
finally{
conn.close();
}
%>
index.html
<HTML>
<HEAD>
<TITLE>圖像測試</TITLE>
</HEAD>
<BODY>
<TABLE>
<TR>
<TD>圖像測試</TD>
</TR>
<TR>
<TD><img src="showimage.jsp?photo_no=1"></TD>
</TR>
</TABLE>
</BODY>
</HTML>
二 LongRaw
建立Table:
CREATE TABLE PHOTO_2
(
PHOTO_NO VARCHAR2(1) NOT NULL,
IMAGE LONG RAW
) showimage.jsp
<%
/**//*
從Oracle數據庫中讀取LongRaw的類型,並且在jsp頁面中顯示出來
*/
%>
<%@ page contentType="text/html; charset=BIG5" %>
<%@ page import="java.io.*"%>
<%@ page import="java.sql.*, javax.sql.*" %>
<%@ page import="java.util.*"%>
<%@ page import="java.math.*"%>
<%
String photo_no = request.getParameter("photo_no");
out.print(photo_no);
//Oracle連結
Class.forName("oracle.jdbc.driver.OracleDriver");
String url="jdbc:oracle:thin:@IP:1521:SID";
String userName="user";
String pwd="pwd";
Connection conn=DriverManager.getConnection(url,userName,pwd);
try{
Statement stmt = conn.createStatement();
String sql = " SELECT * FROM PHOTO_2 WHERE photo_no = "+ photo_no;
ResultSet rs = stmt.executeQuery(sql);
if (rs.next()) {
byte bs[]=rs.getBytes("image");
response.setContentType("image/jpeg");
OutputStream outs = response.getOutputStream();
outs.write(bs);
outs.flush();
rs.close();
}
else {
rs.close();
}
}
finally{
conn.close();
}
%>
PS:這樣的訪問必須要保證這些Blog或LongRaw類型的字段中存儲的是圖片文件。
posted on 2005-08-17 13:13
Java&Inter 閱讀(1501)
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數據庫技術