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Java、XML与数据库编程实践 (四)

 2008-01-05 19:22:04 来源:WEB开发网   
核心提示:PRotected boolean alreadyin(String tname,String colname, String value){ int result;ResultSet rst=null; try { //执行SQL语句String query = "select "+colname

  PRotected boolean alreadyin(String tname,String colname, String value)
  
    {   
  
      int result;
  
      ResultSet rst=null;
  
      try {
  
      //执行SQL语句
  
      String query = "select "+colname+" from "+tname+" where "+colname+"='"+value+"'";
  
      Statement statement = connformax.createStatement();
  
      rst = statement.executeQuery( query );
  
      if(rst.next())
  
      {
  
        statement.close();
  
        rst.close();
  
        return true;
  
      }   
  
     }
  
     catch ( SQLException sqlex ) {
  
      sqlex.printStackTrace();
  
      return false;
  
     }
  
     return false;  
  
    }
  
    protected int getIdfromNumber(String tname,String colname, String value)
  
    {   
  
      int result;
  
      ResultSet rst=null;
  
      try {
  
      Connection conn= DriverManager.getConnection( destPara.getUrl(), destPara.getUsername(),destPara.getPassWord());
  
      String query = "select id,"+colname+" from "+tname+" where "+colname+"='"+value+"'";
  
      System.out.println(query);
  
      Statement statement = conn.createStatement();
  
      rst = statement.executeQuery( query );
  
      if(rst.next())
  
      {
  
        return rst.getInt("id");
  
      }
  
     }
  
     catch ( SQLException sqlex ) {
  
      sqlex.printStackTrace();
  
      return 0;
  
     }
  
     return 0;  
  
    }
  
    /**
  
     * 得到某个表中的最大的id号
  
     */
  
    protected int getMax(String tname)
  
    {   
  
      int result;
  
      ResultSet rst=null;  
  
      try {
  
      //执行SQL语句
  
      String query = "select Max(id) from "+tname;
  
      Statement statement = connformax.createStatement();
  
      rst = statement.executeQuery( query );
  
      if(rst.next())
  
      {
  
        return rst.getInt(1)+1;
  
      }
  
     }
  
     catch ( SQLException sqlex ) {
  
      sqlex.printStackTrace();
  
      return 0;
  
     }
  
     return 1;  
  
    }
  
    /**
  
     * 执行某一段sql语句
  
     */
  
    public static void execute(ConnPara connpara,String stmt) throws SQLException
  
    {
  
      Connection conn=null;
  
      PreparedStatement ps = null;
  
      try {
  
        conn=DriverManager.getConnection( connpara.getUrl(), connpara.getUsername(), connpara.getPassword());
  
        System.out.println(stmt);
  
        ps = conn.prepareStatement(stmt);
  
        ps.executeUpdate();
  
      } catch (Exception e) {
  
        e.printStackTrace();
  
        System.out.println(e.getMessage());
  
      } finally {
  
      if (ps!=null) ps.close();
  
      if (conn!=null)conn.close();
  
      }
  
    }
  
    public static void main(String argc[])
  
    {
  
      DbInput copydb=new DbInput();
  
      copydb.dbInit();
  
      copydb.copyprodUCt(); 
  
    } 
  
  }
  
  问题:
  
  1)    access数据库不能直接由jdbc读写,解决办法是先把access配置在ODBC中,然后再通过ODBC来操作access数据库。

Tags:Java XML 数据库

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