dbidgenerator.java

采用JAVA开发

package com.ywh.dbcp;

import java.util.Vector;
import java.util.List;
import java.util.HashMap;
import java.sql.Connection;
import java.sql.Statement;
import java.sql.ResultSet;
import org.apache.commons.dbcp.ConnectionFactory;

/**
 * <p>Title: 数据库工具类</p>
 * <p>Description: 提供一些数据库使用的类</p>
 * <p>Copyright: Copyright (c) 2002</p>
 * <p>Company: greatom</p>
 * @author 王红宝
 * @version 1.0
 * 对应的最大ID DDL是
 *
 * create table SYMAX_ID(
 *     TABLE_NAME      VARCHAR2(30) not null,
 *     COLUMN_NAME     VARCHAR2(30) not null,
 *     START_VALUE     NUMBER(18) not null,
 *     PREFIX          VARCHAR2(20),
 *     STOP_VALUE      NUMBER(18),
 *     REMARKS VARCHAR2(100), constraint SYMAX_ID_PK primary key (TABLE_NAME,COLUMN_NAME));
 */

public class DBIDGenerator extends PhraseIDGenerator
{

  public DBIDGenerator(ConnectionFactory factory,
                       int length, String tbName, String column)
  {
    super(length, tbName);
    this.column = column;
    this.factory = factory;
  }
  protected void refresh()
  {
    Connection conn = null;
     try
     {
       if ( factory == null ){
         System.out.println("connection factory is null!");
       }
       conn = factory.createConnection();
       Statement stmt = null;
       ResultSet rs = null;
       conn.setAutoCommit(true);  // temporary workaround, should throw exception instead
       stmt = conn.createStatement();
       stmt.executeUpdate("UPDATE SYMAX_ID SET START_VALUE = START_VALUE + " +
                          _originLength + " WHERE TABLE_NAME = '" + _tableName.toUpperCase() +
                          "' AND COLUMN_NAME='" + column.toUpperCase() + "'");
       rs = stmt.executeQuery("SELECT START_VALUE FROM SYMAX_ID WHERE TABLE_NAME = '" + _tableName.toUpperCase() +
                              "' AND COLUMN_NAME='" + column.toUpperCase() + "'");
       if(!rs.next())
       {
         throw new Exception("Maxids table has no row for table " + _tableName.toUpperCase() +
                             " and column for " + column);
       }
       _minID = rs.getInt(1) - _originLength;
       _length = _originLength;
       rs.close();
       stmt.close();
     }catch(Exception e)
     {
       e.printStackTrace();
     }finally{
       if ( conn != null ){
         try
         {
         conn.close();
         }catch(Exception e)
         {
           e.printStackTrace();
         }
       }
     }
  }

  private String column;
  private ConnectionFactory factory;
}