sequenceutil.java

EJB 开发 EJB 开发 EJB 开发 EJB 开发 EJB 开发 EJB 开发

package employee;

import java.sql.*;
import javax.naming.NamingException;
import java.util.*;
import java.io.*;
public class SequenceUtil
{
  //下面的函数产生序列器
  public static String getSequence(String tablename) throws NamingException,SQLException
  {
    String sql = "SELECT REPLACE(LPAD(" + tablename + ".NEXTVAL,12),' ','0') FROM DUAL";
    String sec = "";
    Connection conn = null;
    try
    {
      conn = EjbCommon.getLocalConnection();
      PreparedStatement ps = conn.prepareStatement(sql);
      ResultSet rs = ps.executeQuery();
      while (rs.next())
      {
        sec = rs.getString(1);
      }
    }
    catch (NamingException e) {throw e;}
    catch (SQLException e) {throw e;}
    finally
    {
      try
      {
        if (conn != null) {conn.close();}
      }
      catch (SQLException e1) {throw e1;}
      finally { }
    }
    return sec;
  }
  public static String getSequence()
  {
    long id = System.currentTimeMillis();
    String seq = Long.toString(id);
    return seq;
  }
  public static String getUniteCode()
  {
    String code = "";
    code = "ID_";
    java.sql.Date dt = new java.sql.Date(System.currentTimeMillis());
    code += dt.toString(); //而如果这么用的话，得到的是：ID_2003072404CB077B81059026110484。这才是我们想要的ID
    code += getPhysicalAddress().substring(4);
    code += getSequence();
    int pos = 0;
    while (code.lastIndexOf("-") > 0)
    {
      pos = code.lastIndexOf("-");
      code = code.substring(0, pos) + code.substring(pos + 1, code.length());
    }
    return code;
  }
  //上面的函数产生序列器
  //取得网卡的物理地址开始（说明：这一段代码是易建公司的人写的，值得研究）
  private static String _strPhysicalAddress;
  private static final int _physicalLength = 16;
  static public String getPhysicalAddress()
  {
    if (_strPhysicalAddress == null || _strPhysicalAddress.trim().equals(""))
    {
      String cmd = "cmd.exe /c ipconfig/all";
      Vector result;
      result = execute(cmd);
      _strPhysicalAddress = parseCmd(result.toString());
    }
    return _strPhysicalAddress;
  }
  //从字符串中解析出所需要获得的字符串
  static private String parseCmd(String s)
  {
    String find = "Physical Address. . . . . . . . . :";
    int findIndex = s.indexOf(find);
    if (findIndex == -1)
      return "no net adapter";
    else
      return s.substring(findIndex + find.length() + 1,findIndex + find.length() + 2 + _physicalLength);
  }
  //运行ipconfig命令，并且自动捕捉输出。这一段代码值得研究！
  private static Process _p;
  public static Vector execute(String shellCommand)
  {
    try
    {
      Start(shellCommand);
      Vector vResult = new Vector();
      DataInputStream in = new DataInputStream(_p.getInputStream());
      BufferedReader reader = new BufferedReader(new InputStreamReader(in));

      String line;
      do
      {
        line = reader.readLine();
        if (line == null)
        {
          break;
        }
        else
        {
          vResult.addElement(line);
        }
      }
      while (true);
      reader.close();
      return vResult;
    }
    catch (IOException e)
    {
      return null;
    }
  }
  //开始执行
  public static void Start(String shellCommand) throws IOException
  {
    try
    {
      if (_p != null)
      {
        kill();
      }
      Runtime sys = Runtime.getRuntime();
      _p = sys.exec(shellCommand);
    }
    catch (IOException e)
    {
      throw e;
    }
  }
  /**	kill this process */
  public static void kill()
  {
    if (_p != null)
    {
      _p.destroy();
      _p = null;
    }
  }
  //取得网卡的物理地址结束
  public SequenceUtil(){}
}