操作clob类型

   Clob clob = null;  String content=null; //帖子内容  clob = rs.getClob(4);  if(clob == null){   //clob为空时 内容为空                content = null;                      }else{                   long len = clob.length();  //获得内容    content = clob.getSubString(1, (int) len);          }