Oracle读取二进制BLOB类型数据出现乱码

JAVA中，读取Oracle中二进制BLOB类型数据，出现乱码.. 如果BLOB是文本类型存储的就不会存在乱码
BLOB blob = (oracle.sql.BLOB)rs.getBlob("ys1");
try{

FileOutputStream outStream = new FileOutputStream("c:/oracleback1.txt");

InputStream inStream = blob.getBinaryStream();

byte[] buf = new byte[1024];

int len;

while ((len = inStream.read(buf)) > 0) {

outStream.write(buf, 0, len);

}

inStream.close();

outStream.close();

}catch(Exception e) {

e.printStackTrace();

}
}

BLOB 用来存二进制类型 本来就没有编码 存文本用CLOB