таблица mtable
полетипidintegerdatalongblobnamevarchar(255)
считывание контента
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String qry = "select data from mtable where id = " + id;
Statement st = con.createStatement();
ResultSet rs = st.executeQuery(qry);
if (rs.next()) {
InputStream in = rs.getBinaryStream("data");
BufferedInputStream bin = new BufferedInputStream(in);
int readed = - 1 ;
while ((readed = bin.read()) != - 1 ) {
out.write(readed); // out в данном случае - OutputStream некого сервлета
}
bin.close();
}
rs.close();
st.close();
вставка/апдейт, например, из файла
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File file = new File("c:\\content.doc");
FileBlobImpl fblob = new FileBlobImpl(file);
String qry = "update mtable set data = ? where id = " + id;
PreparedStatement pst = con.prepareStatement(query);
pst.setBlob( 1 , fblob);
pst.executeUpdate();
pst.close();
класс FileBlobImpl очень прост
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import java.sql.*;
import java.io.*;
public class FileBlobImpl implements Blob {
private File file;
public FileBlobImpl(File file) {
this .file = file;
}
public long length() throws SQLException {
return file.length();
}
public byte [] getBytes( long pos, int length) throws SQLException {
if (pos + length >= length())
throw new SQLException("Bad lenght");
try {
RandomAccessFile raf = new RandomAccessFile(file, "r");
raf.seek(pos);
byte [] bytes = new byte [length];
for ( int i = 0 ; i < bytes.length; i++) {
bytes[i] = raf.readByte();
}
return bytes;
} catch (FileNotFoundException e) {
throw new SQLException("File is not found :" + e.toString());
} catch (IOException e) {
throw new SQLException("IO Exception while reading this file:" + e.toString());
}
}
public InputStream getBinaryStream() throws SQLException {
try {
return new FileInputStream(file);
} catch (FileNotFoundException e) {
throw new SQLException("File is not found :" + e.toString());
}
}
public long position( byte pattern[], long start) throws SQLException {
throw new UnsupportedOperationException();
}
public long position(Blob pattern, long start) throws SQLException {
throw new UnsupportedOperationException();
}
public int setBytes( long pos, byte [] bytes) throws SQLException {
throw new UnsupportedOperationException();
}
public int setBytes( long pos, byte [] bytes, int offset, int len) throws SQLException {
throw new UnsupportedOperationException();
}
public OutputStream setBinaryStream( long pos) throws SQLException {
throw new UnsupportedOperationException();
}
public void truncate( long len) throws SQLException {
throw new UnsupportedOperationException();
}
}
