問題描述

如何使用 jdbc 將整個表寫入平面文件(文本文件)?到目前為止，我嘗試了以下方法:

How do I to write an entire table to a flat file (text file) using jdbc? So far I've attempted the following:

Statement statement = connection.createStatement();
   ResultSet result = statement.executeQuery("SELECT * FROM tablename");
   BufferedInputStream buffer;
   FileOutputStream out = new FileOutputStream("flatfile.txt");
   while(result.next() )
   {
      buffer =  new BufferedInputStream(result.getBinaryStream("????") );
      byte[] buf = new byte[4 * 1024]; //4K buffer
      int len;
      while( (len = buffer.read(buf, 0, buf.length) ) != -1 )
      {
          out.write(buf, 0, len );
      }
   }
   out.close();

???"只是我的占位符.我被困在作為參數傳遞的內容上.

"????" is just my placeholder. I am stuck on what to pass in as an argument.

推薦答案

您可以使用下面的代碼從表中獲取所有列名和整個數據.writeToFile 方法將包含寫入文件的邏輯(如果這還不夠明顯:))

You can get all the column names and the entire data from your table using the code below. writeToFile method will contain the logic to writing to file (if that was not obvious enough :) )

    ResultSetMetaData metadata = rs.getMetaData();
    int columnCount = metadata.getColumnCount();    
    for (int i = 1; i <= columnCount; i++) {
        writeToFile(metadata.getColumnName(i) + ", ");      
    }
    System.out.println();
    while (rs.next()) {
        String row = "";
        for (int i = 1; i <= columnCount; i++) {
            row += rs.getString(i) + ", ";          
        }
        System.out.println();
        writeToFile(row);

    }

這篇關于如何使用 jdbc 中的 ResultSet.getBinaryStream() 從所有列中獲取值?的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網！