clob相关的咚咚以及字符串处理

1.方法把ArrayList里面的字符串拼成一个大字符串，并且每行后面加一个“\r”，也就是oracle数据库中的chr(13).

  public static void WriteClob() throws Exception {

    ArrayList content = new ArrayList();
    String back_string = "";
    String flag = "\r";
    content.add("line1");
    content.add("line2");
    content.add("line3");
    content.add("line4");
    content.add("line5");
    content.add("line6");

    for (int i = 0; i < content.size(); i++) {
      back_string += content.get(i) + flag;
    }

    PreparedStatement pst = null;
    ResultSet rs = null;
    String sql = null;
    Connection conn = DBUtil.getConnection();
    conn.setAutoCommit(false);

    try {

      //update clob field to empty_clob();
      sql = "update clob_test set c = empty_clob()";
      pst = conn.prepareStatement(sql);
      pst.executeUpdate();
      pst = null;
      sql = " select c from clob_test for update";
      pst = conn.prepareStatement(sql);
      rs = pst.executeQuery();
      if (rs.next()) {
        Clob clob = rs.getClob("C");
        Writer outstream = clob.setCharacterStream(0);
        outstream.write(back_string);
        outstream.flush();
        outstream.close();
        conn.commit();
      }

    } catch (Exception e) {
      throw e;
    } finally {
      DBUtil.close(rs, pst, conn);
    }
  }


2。get clob from oracle：
  public static void getClob() throws
      Exception {

    String sql = null;
    Connection conn = DBUtil.getConnection();
    PreparedStatement pst = null;
    ResultSet rs = null;
    StringBuffer buf = new StringBuffer();
    try {
      sql = "select c from clob_test"
          ;
      pst = conn.prepareStatement(sql);
      rs = pst.executeQuery();
      if (rs.next()) {
        Clob clob = rs.getClob(1);
        Reader instream = clob.getCharacterStream();
        long length = clob.length();
        for (long l = 1; l < length; l += 1024) {
          buf.append( (clob.getSubString(l, 1024)));
        }

        String ss = buf.toString();
        String tos;
        byte b[] = ss.getBytes("UTF-8");
        for (int j = 0; j < b.length; j++) {
          tos = Integer.toHexString(b[j]);
          System.out.println("Integer.toHexString(b[" + j +
                             "])================>" + tos);
        }

        System.out.println("buf.toString.length()====:>" +
                           buf.toString().length());
        System.out.println("buf.toString====:>" + buf.toString());

        System.out.println("clob length ===>" + length);
      }

    } catch (Exception e) {
      System.err.println(sql);
      e.printStackTrace();
    } finally {
      DBUtil.close(rs, pst, conn);
    }

  }


3.
  /**
   * 得到上载文本的内容，以ArrayList返回，其中每个元素是文本文件的一行，为字符串
   * @param request MultipartRequest
   * @return ArrayList
   */
  public ArrayList getUploadedFileContent(MultipartRequest request) {
    ArrayList fileContent = new ArrayList();
    try {
      System.out.println(
          "getUploadedFileContent functional is processing========begin================>");

      File file = request.getFile( (String) request.getFileNames().nextElement());
      FileReader fileReader = new FileReader(file);
      BufferedReader bufferedReader = new BufferedReader(fileReader);
      boolean eof = false;
      while (!eof) {
        String line = bufferedReader.readLine();
        if (line == null) {
          eof = true;
        } else {
          fileContent.add(line);
        }
      }
      bufferedReader.close();
    } catch (IOException e) {
      e.printStackTrace();
    } catch (Exception e) {
      e.printStackTrace();
    }
    System.out.println(
        "getUploadedFileContent functional is processing========begin================>");
    return fileContent;
  }


4。自定义异常类：
public class MyException extends Exception {
  public MyException () {
    super();
  }
  public MyException (String errorMsg){
    super(errorMsg);
  }
}


5.
从数据库中取道clob内容，以\r为分隔符，取到一个ArrayList里面去：

  public static void StringTokenSplit() throws Exception {
    String ss;
    ss = getClob();
    ArrayList content = new ArrayList();
    System.out.println("ss========================>:\n"+ss);

    StringTokenizer st = new StringTokenizer(ss,"\r",false);
    while(st.hasMoreTokens()){
    content.add(st.nextToken());
     }

     for( int i = 0; i< content.size(); i++) {
       System.out.println(" content.size()======================>:\n"+ content.size());
       System.out.println(" content.get("+i+")======================>:\n"+ content.get(i));
     }

  }