jdbc 처리 oracle 의 clob 필드 에 대한 상세 한 설명

import java.io.BufferedOutputStream;import java.io.ByteArrayInputStream;import java.io.IOException;import java.io.InputStream;import java.io.OutputStream;import java.io.Reader;import java.sql.Clob;import java.sql.Connection;import java.sql.ResultSet;import java.sql.SQLException;

public class ClobUtil {

 /**
  * 
  * @param insertSQL   sql    clob   ，      empty_clob()    :insert into ba valus(1,empty_clob())
  * @param updateSQL          ,        . ：select * from BA where ba_id = '"+ba.getBA_id()+"' for update
  * @param con      
  * @param bigString     clob 
  * @param updateColumn         
  * @return
  * @throws SQLException
  */
 public static Boolean clobInsert(String insertSQL,String updateSQL,Connection con,String bigString,String updateColumn ) throws SQLException{ 
      //    
      ResultSet rs = null;
      //       sql
      String query = insertSQL;
      //        
      con.setAutoCommit(false);
      //      
      java.sql.PreparedStatement pstmt = con.prepareStatement( query);
      //       
      pstmt.executeUpdate();
      //  
      pstmt = null;
      //     
      query = updateSQL; 
         //           select
      pstmt = con.prepareStatement(query); 
      rs = pstmt.executeQuery(); 
      //            
      if(rs.next())  
      { 
        //      clob   
        oracle.sql.CLOB singnaturedateClob = (oracle.sql.CLOB)rs.getClob(updateColumn);  
        //  clob         
        BufferedOutputStream out = new BufferedOutputStream(singnaturedateClob.getAsciiOutputStream());
        //            
        if(bigString!=null){
        try{
         //              
         InputStream  is = (InputStream)(new   ByteArrayInputStream(bigString.getBytes()));  
      copyStream( is, out );
      out.close();
    } catch (IOException e) {
     // TODO Auto-generated catch block
     e.printStackTrace();
    }
        }
      } 
      rs.close();
      con.commit();

   return true;
 }
 /**
  *             
  * @param is    
  * @param os    
  * @throws IOException
  */ 
 public static void copyStream( InputStream is, OutputStream os )
 throws IOException
 {
  byte[] data             = new byte[4096];
  int readed              = is.read(data);
  while (readed != -1)
  {
   os.write(data,0,readed);
   readed = is.read(data);
  }
 }

 /**
  *   Clob       
  * @param c
  * @return
  */
 public static String getClobString(Clob c) {  
        try { 

            Reader reader=c.getCharacterStream();
            if (reader == null) { 
                return null; 
            } 
            StringBuffer sb = new StringBuffer(); 
            char[] charbuf = new char[4096]; 
            for (int i = reader.read(charbuf); i > 0; i = reader.read(charbuf)) { 
                sb.append(charbuf, 0, i); 
            } 
            return sb.toString(); 
        } catch (Exception e) { 
            return ""; 
        } 
    }
}