为什么用sqlserverjdbc读取text字段值到1596个字符后，后面变乱码了？

Question

谢谢楼上几位热心帮助，这个问题解决了
但又来了个新问题，发现读取７Ｋ的内容时，竟然要花我５分多钟时间，速度奇慢，请大家再次帮下忙，解决后马上给分

Answer 1

帖代码吧，不然怎么知道问题

Answer 2

下面就是我读取ＴＥＸＴ字段的关键代码：
sqlStmt = sqlCon.createStatement();
sqlRst = sqlStmt.executeQuery(strSQL);
 ....
                          try{
                             Reader sr = sqlRst.getCharacterStream(6);
                             StringBuffer sb = new StringBuffer();
                             char[] b = new char[512];
                             int len = -1;
                             while ((len = sr.read(b)) > 0){
                               sb.append(b,0,len);
                             }
                             if (sb.length() > 0){
                               out.println(sb.length());
                              out.print(sb.toString());
                             }
                             sr.close();
                          }
                          catch (Exception e){
                             out.println(读大文本出错：" + e.getMessage());
                          }
.....

Answer 3

且读出的结果中，有些字符变乱码了