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blob字段

原创 Linux操作系统 作者:nkyy27 时间:2012-06-20 23:10:38 0 删除 编辑
日志文章
2006年12月31日 16:08:45
Oracle中插入图片并显示(用BLOB类型)
要在oracle里面存入图片 用 blob类型


首先在数据库里建立:

--连接到管理员
conn sys/tbsoft as sysdba;

--为scott用户授权

grant create any directory to scott;

--回到scott用户

conn scott/tiger;


--创建存储图片的表
CREATE TABLE IMAGE_LOB (T_ID VARCHAR2 (5) NOT NULL,T_IMAGE BLOB NOT NULL);

--创建存储图片的目录
CREATE OR REPLACE DIRECTORY IMAGES AS 'C:\picture';

--在c:下自己建一个叫picture的文件夹

CREATE OR REPLACE PROCEDURE IMG_INSERT (TID VARCHAR2,FILENAME VARCHAR2) AS
F_LOB BFILE;--文件类型
B_LOB BLOB;
BEGIN
iNSERT INTO IMAGE_LOB (T_ID, T_IMAGE)
VALUES (TID,EMPTY_BLOB ()) RETURN T_IMAGE INTO B_LOB;
--插入空的blob
F_LOB:= BFILENAME ('IMAGES', FILENAME);
--获取指定目录下的文件
DBMS_LOB.FILEOPEN(F_LOB, DBMS_LOB.FILE_READONLY);
--以只读的方式打开文件
DBMS_LOB.LOADFROMFILE (B_LOB, F_LOB,DBMS_LOB.GETLENGTH (F_LOB));
--传递对象
DBMS_LOB.FILECLOSE (F_LOB);
--关闭原始文件
COMMIT;
END;
/


--在C:\picture下放一张图片1.gif

--将该图片存入表
call IMG_INSERT('1','1.gif');


然后创建一个web项目 连接数据库后 创建一个BlobDAO类 用来取出表中的blob类型图片

public class BlobDAO {

private static final BlobDAO instance = new BlobDAO();

private Connection conn = null;

private BlobDAO() {

}

public static BlobDAO getInstance() {
return instance;
}

private void initConn() {
conn = DBAccess.getInstance().getConn();
}


public byte[] getImage(String imgname) {
BufferedInputStream ins;//取得BLOB的IO流
byte[] bt = null;

initConn();
Blob bo = null;
PreparedStatement ps = null;
ResultSet rs = null;
String sql = "select T_IMAGE from IMAGE_LOB where t_id=?";
try {
ps = conn.prepareStatement(sql);
ps.setString(1, imgname);
rs = ps.executeQuery();
if (rs.next()) {
bo = rs.getBlob("T_IMAGE");

try {
ins = new BufferedInputStream(bo.getBinaryStream());
int bufferSize = (int) bo.length();//取得BLOB的长度
bt = new byte[bufferSize];
try {
ins.read(bt, 0, bufferSize);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
//建立字节缓存
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} finally {
try {
rs.close();
ps.close();
conn.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}

return bt;
}
}


在action里面调用getImage()方法并显示图片在页面上

public ActionForward execute(ActionMapping mapping, ActionForm. form,
HttpServletRequest request, HttpServletResponse response) {
// TODO Auto-generated method stub

BlobDAO blobDAO = BlobDAO.getInstance();

byte[] bs = blobDAO.getImage("1");

try {

response.getOutputStream().write(bs);

} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

return null;
}

添加图片到数据库

请在c盘下放入图片--c:\\4.gif

public void savaImg(String imgId) {
//传的是存入数据库图片的id
initConn();
Statement st = null;
BLOB blob = null; //图片类型
OutputStream utputStream = null; //输出流
File file = null; //文件
InputStream inputStream = null; //输入流
ResultSet rs = null;
try {
conn.setAutoCommit(false); //事物由程序员操作
st = conn.createStatement();
st.executeQuery("insert into IMAGE_LOB values('"+ imgId +"',empty_blob())");
rs = st.executeQuery("select T_IMAGE from IMAGE_LOB where t_id='"+ imgId +"' for update");
if (rs.next()) {
blob = (BLOB) rs.getBlob(1);
utputStream = blob.getBinaryOutputStream();
file = new File("c:\\4.gif");
inputStream = new FileInputStream(file);
byte[] b = new byte[blob.getBufferSize()];
int len = 0;
while ((len = inputStream.read(b)) != -1) {
System.out.println(len);
outputStream.write(b, 0, len);
}
}

} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} finally {
try {
inputStream.close();
outputStream.flush();
outputStream.close();
rs.close();
st.close();
conn.commit();
conn.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

}
}



操作完毕!

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