Read Blob type from oracle

• • Reply

  18 years ago

  by jacksu

  su yu

  NY,US, United States

  Joined 18 years ago

  Hi,
  

  
  Access string type of data from oracle is easy, but access blob type is not. here is one example, requires: JDK1.4, classes111.zip from oracle 8.1.5 +,
  

  
  import java.sql.;
  import java.io.;
  import java.util.;
  import oracle.jdbc.driver.;
  

  
  //needed for new CLOB and BLOB classes
  import oracle.sql.*;
  

  
  public class JBlob {
     public static void main(String args[]) throws Exception {
  

  
         DriverManager.registerDriver(new oracle.jdbc.driver.OracleDriver());
         Connection conn=DriverManager.getConnection("jdbcracle:thin123.123.123.123:1521rcl", "dbusername", "dbpassword");
         conn.setAutoCommit (false);
  

  
  

  
         Statement stmt = conn.createStatement();
         try {
             stmt.execute ("drop table SessionTable");
             System.out.println("Table droped ...");
         }
         catch (Exception e) {
             System.out.println("Table does not exist");
         }
         
  System.out.println("creating table");
         // Create the table
         stmt.execute ("create table SessionTable (mysession varchar2(200), myobject BLOB)");
         System.out.println("Table created ...");
         
         stmt.execute("insert into SessionTable values('session1', empty_blob())");
         stmt.execute("commit");
  

  
  System.out.println("inserted");        
         String cmd = "select mysession, myobject from SessionTable for update";
         oracle.jdbc.driver.OracleResultSet rset = ( oracle.jdbc.driver.OracleResultSet)stmt.executeQuery(cmd);
  

  
  System.out.println("reading...");
     ByteArrayOutputStream bout = new ByteArrayOutputStream();
     ObjectOutputStream oout = new ObjectOutputStream(bout);
     oout.writeObject("jack su yu testing string");
     oout.writeInt(134);
     byte buf[] = bout.toByteArray();
  

  
         while (rset.next()) {
  

  
         BLOB blob = ((OracleResultSet)rset).getBLOB(2);
  

  
         OutputStream out = blob.getBinaryOutputStream();
         int chunk = blob.getChunkSize();
         int pos = 0;
         while (pos < buf.length) {
             out.write(buf, pos, chunk);
             pos += chunk;
         }    
         out.close();
         System.out.println("writen to blob");
  

  
  

  
  

  
         InputStream in = blob.getBinaryStream();
         bout = new ByteArrayOutputStream();
         buf = new byte[chunk];
         int l;
         while ((l = in.read(buf)) != -1) {
             bout.write(buf, 0, l);
         }
         buf = bout.toByteArray();
         in.close();
         ObjectInputStream oin = new ObjectInputStream(new ByteArrayInputStream(buf));
         System.out.println(oin.readObject());
         System.out.println(oin.readInt());
         }
         
         
         stmt.close();
     }
  }
  

  Report abuse