import java.sql.*;
import java.io.*;
/*
 *將CodeHelp數據庫中的文件導出
 *@version 2009-3-15
 *@author Winty (wintys@gmail.com)
 */
class CodeHelpExporter{
    Database db;//數據庫連接對象

    public CodeHelpExporter(String dbPath){
        db = new Database(dbPath);
        try{
            db.connect();
        }catch(SQLException sqle){
            sqle.printStackTrace();
        }
    }

    /**
     *主函數
     */
    public static void main(String[] args){
        String dbq = "helpdb.mdb";
        CodeHelpExporter exporter = new CodeHelpExporter( dbq );
        exporter.export();
    }

    /**
     *按CodeHelp的目錄結構導出文章及其附件。
     *但有一點不同，就是不含任何內容的目錄不會被創建。
     *文章會被導出到當前目錄的CodeHelpExportedFiles目錄下。
     */
    public void export(){
        try{
            String sql;
            sql = "SELECT T.NodeId AS id , T.ParentId AS parent ,";
            sql +="T.Type AS type,T.Title AS title , C.Content AS content ";
            sql +="FROM TContent C, TTree T WHERE T.NodeId = C.NodeId ";
            ResultSet rs = db.query(sql);

            while(rs.next()){
                int type = rs.getInt("type");
                if(type == 0)//如果是目錄，則無操作
                    continue;

                int parent = rs.getInt("parent");
                int id = rs.getInt("id");
                String title = rs.getString("title");

                File fullParentPath = null;
                fullParentPath = parentPath(parent , "");
                fullParentPath = new File("CodeHelpExportedFiles/" +
                                                        fullParentPath.toString() );
               
                //讀取附件的SQL
                String sql2 = "SELECT A.Title AS title , A.Data AS data ";
                sql2 += "FROM TAttachment A WHERE A.NodeId = " + id;
                ResultSet rs2=db.query(sql2);

                //判斷文章有沒有附件
                //如果文章沒有附件則不創建目錄，即文章不包含在目錄中
                rs2.last();
                int num = rs2.getRow();
                String article;
                if(num > 0){
                    article = title + "/" ;
                }
                else{
                    article = "";
                }
                fullParentPath = new File(fullParentPath , article);
                if(!fullParentPath.exists())
                    fullParentPath.mkdirs();
                   
                //讀取文章
                InputStream input = rs.getAsciiStream("content");
                readDataToFile(new File(fullParentPath ,  title + ".txt") , input);

                //讀取文章的附件
                rs2.beforeFirst();
                while(rs2.next()){
                    String attachmentName = rs2.getString("title");
                    InputStream data = rs2.getBinaryStream("Data");
                    //將附件與其文章一同放在以文章名為目錄名的目錄中
                    readDataToFile(new File(fullParentPath , attachmentName) ,
                                            data);
                }
                rs2.close();
            }
            rs.close();

        }catch(Exception e){
            e.printStackTrace();
        }finally{
            try{
                db.close();
            }catch(Exception e){
                e.printStackTrace();
            }
        }
    }

    /**
     *從數據流中讀取數據到文件
     *@param fileName 輸出文件的文件名
     *@param input 數據輸入流
     */
    private void readDataToFile(File filePath , InputStream input)
        throws IOException{
        FileOutputStream file = new FileOutputStream(filePath);
        BufferedOutputStream output = new BufferedOutputStream(file);

        byte[] buf = new byte[1024];
        int len;
        while((len = input.read(buf))!=-1){
            output.write(buf , 0 , len);
        }

        input.close();
        output.close();
    }

    /**
     *遞歸地構造目錄(如果父目錄存在的話)。即如果是子目錄，則一直找到根目錄才返回。
     *@param parent 父目錄的ParentId
     *@param title 文件自身目錄名，對于文章而言，path總是傳入空字符串。
     *@return 返回構造后的目錄(含從根目錄一直到子目錄的各級目錄)
     */
    private File parentPath(int parent , String path)
        throws IOException , SQLException{
      
        if(parent == 0){//根目錄
            File dir = new File(path);
            return dir;
        }
        else{
            String sql = "SELECT Title , ParentId  FROM TTree ";
            sql += "WHERE NodeId=" + parent;
            ResultSet rs = db.query(sql);
           
            if(rs.next()){
                String nodeTitle = rs.getString("Title");
                int nodeParent = rs.getInt("ParentId");
                path = nodeTitle + "/" + path;

                return parentPath(nodeParent , path);
            }
            rs.close();
        }

        return null;///
    }
}

import java.sql.*;
import java.io.*;

/**
 *數據庫操作類，當前只適用于Access數據庫。
 *@version 2009-3-15
 *@author wintys@gmail.com
 */
class Database{
    private Connection conn = null;
    private String dbPath = null;

    /**
     *構造方法
     *@param databasePath Access數據庫的路徑
     */
    public Database(String databasePath){
        dbPath = databasePath;
    }

    /**
     *連接數據庫
     *@return 返回一個數據庫連接Connection，如果連接數據庫失敗，返回null。
     */
    public Connection connect()
        throws SQLException{

        if(conn!=null)
            return conn;
       
        if(dbPath==null || dbPath.equals("")){
            conn = null;
            throw new SQLException("數據庫路徑錯誤!");
        }
       
        String url;
        //Microsoft Access數據庫連接字符串
        url = "jdbc:odbc:driver={Microsoft Access Driver (*.mdb)};DBQ=";
        url += dbPath;
       
        try{
            Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
        }catch(ClassNotFoundException e){
            e.printStackTrace();
        }
        conn = DriverManager.getConnection(url , "" , "");
       

        return conn;
    }

    /**
     *關閉數據庫連接
     */
    public void close() throws SQLException{
        if(conn!=null)
            conn.close();
    }

    /**
     *執行查詢，調用者要負責關閉結果集。
     *@param sql 要執行的SQL查詢語句
     *@return 返回查詢結果集
     */
    public ResultSet query(String sql) throws SQLException{
        Statement stmt;
        stmt = conn.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE ,
                                                      ResultSet.CONCUR_UPDATABLE);
        ResultSet rs = stmt.executeQuery(sql);

        return rs;
    }
}