在java中更新Clob添加额外的char

Question

我有一个程序从文件中读取xml并更新clob。看起来这个程序在clob的末尾添加了额外的字符，有人可以让我知道缺少什么。

public class  UpdateClob {  
@SuppressWarnings("deprecation")
public static void main(String[] args) throws Exception  {
         {

    FileInputStream     ifs    = null;
    OutputStream        COS        = null;
    String              sqlText1                 = null;
    Statement           stmt                    = null;
    ResultSet           rset                    = null;
    CLOB                xmlDocument             = null;
    int                 bufferSize;
    byte[]              byteBuffer;
    int                 bytesRead               = 0;

    int                 totBytesRead            = 0;
    int                 totBytesWritten         = 0;
    Connection      conn                = null;
    File            input     = null;
      conn=getConnection();
     stmt = conn.createStatement();
     Clob myClob = conn.createClob();
     input = new File("C:\Test.xml");
     ifs = new FileInputStream(input);

     sqlText1 = "SELECT xml_doc FROM   table_name    FOR UPDATE";
     rset = stmt.executeQuery(sqlText1);
     rset.next();
     xmlDocument = ((OracleResultSet) rset).getCLOB("xml_doc");
     bufferSize = xmlDocument.getBufferSize();
     byteBuffer = new byte[bufferSize];
     COS= xmlDocument.getAsciiOutputStream();           
     while ((bytesRead = ifs.read(byteBuffer)) != -1) {
        COS.write(byteBuffer, 0, bytesRead);
        totBytesRead += bytesRead;
        totBytesWritten += bytesRead;
     }

     ifs.close();
     COS.close();

     conn.commit();
     rset.close();
     stmt.close();

}}