dbbackup.java

数据库备份程序示例

//Copyright 1998 John Wiley and Sons, Inc.

import java.io.*;
import java.util.*;
import java.net.*;
import java.sql.*; 

public class DBBackup extends Object
{
    Connection connection;
    Statement statement;
    String xmlFile;
    String tableToSave;
    
    public DBBackup(String url, String driverName,
                       String user, String passwd,
                       String file, String table)
    {
        try
        {
            //load the driver
            Class.forName(driverName);

            connection = 
                    DriverManager.getConnection(url, user, passwd);
                    
            statement = connection.createStatement();
            
            xmlFile = file;
            tableToSave = table;
        }
        catch (Exception exp)
        {
            System.out.println("Error connecting: "+exp);
        }    
     }

    public void performBackup()
    {
        DatabaseMetaData dbMetaData;
        ResultSet tables=null;
        ResultSet resultSet=null;
        ResultSetMetaData metaData;
        Vector allTables = new Vector();
        PrintWriter out;
        String tableName,colName;
        int curType;
        int i,max;
        byte[] rawData;
        int j,rawMax;
        int k,maxTables;
        String data;
        
        try
        {
            out = new PrintWriter(
                                  new BufferedWriter(
                                  new FileWriter(xmlFile)));
            
            if(tableToSave == null)
            {
                dbMetaData = connection.getMetaData();
                tables = dbMetaData.getTables("","",null,null);
            
                while(tables.next())
                {
                    allTables.addElement(tables.getString("TABLE_NAME"));
                    System.out.println("Adding "+tables.getString("TABLE_NAME")+" to table list.");
                }
            
                tables.close();
            }
            else
            {
                allTables.addElement(tableToSave);
            }
            
            maxTables = allTables.size();
            
            out.println("<?xml version=\"1.0\"?>");
            out.println("<!DOCTYPE jdbc SYSTEM \"jdbc.dtd\">");
            out.println();
            out.println("<DATABASE>");
            
            for(k=0;k<maxTables;k++)
            {
                tableName = (String) allTables.elementAt(k);
                
                out.println("<TABLE NAME=\""+tableName+"\">");
                
                resultSet = statement.executeQuery("select * from "
                                                         +tableName);
                                                         
                metaData = resultSet.getMetaData();

                max = metaData.getColumnCount();

                while(resultSet.next())
                {
                    out.println("<ROW>");
                    
                    for(i=1;i<=max;i++)
                    {
                        curType = metaData.getColumnType(i);
                        colName = metaData.getColumnLabel(i);

                        switch(curType)
                        {
                            case Types.CHAR:
                            case Types.VARCHAR:
                            case Types.LONGVARCHAR:
                            case Types.BINARY:
                            case Types.VARBINARY:
                            case Types.LONGVARBINARY:
                                data = resultSet.getString(i);
                                
                                if(data == null) data = "";
                                else data = URLEncoder.encode(data);
                                
                                out.print("<TEXT NAME=\""+colName+"\">");
                                out.print(data);
                                out.println("</TEXT>");
                                break;

                            case Types.TINYINT:
                            case Types.SMALLINT:
                            case Types.INTEGER:
                            case Types.BIGINT:
                                out.print("<NUMERIC NAME=\""+colName+"\">");
                                out.print(resultSet.getLong(i));
                                out.println("</NUMERIC>");
                                break;
                                
                            case Types.FLOAT:
                            case Types.DOUBLE:
                                out.print("<NUMERIC NAME=\""+colName+"\">");
                                out.print(resultSet.getDouble(i));
                                out.println("</NUMERIC>");
                                break;

                            case Types.DATE:
                                out.print("<TEXT NAME=\""+colName+"\">");
                                out.print(resultSet.getDate(i));
                                out.println("</TEXT>");
                                break;

                            case Types.TIME:
                                out.print("<TEXT NAME=\""+colName+"\">");
                                out.print(resultSet.getTime(i));
                                out.println("</TEXT>");
                                break;

                            case Types.TIMESTAMP:
                                out.print("<TEXT NAME=\""+colName+"\">");
                                out.print(resultSet.getTimestamp(i));
                                out.println("</TEXT>");
                                break;

                            default:
                                //do nothing
                        }
                    }
                    
                    out.println("</ROW>");
                }
                resultSet.close();
                
                out.println("</TABLE>");
            }
        
            out.println("</DATABASE>");
            out.close();
        }
        catch (Exception exp)
        {
            System.out.println("Error performing backup: "+exp);
        }    
    }

    public void close()
    {
        try
        {
            statement.close();
            connection.close();
        }
        catch (Exception exp)
        {
            System.out.println("Error closing DB connection: "+exp);
            exp.printStackTrace();
        }    
    }
    
    public static void main(String args[])
    {
        String url=null,driver=null,user=null;
        String password=null,file=null,table=null;
        DBBackup backup;
        int i,max;
        
        if ((args != null) && (args.length > 1)) 
        {
            max = args.length;
            
            for (i = 0;i < max;i++)
            {
                if (args[i].equals("-url")) 
                    url = args[++i];
                else if (args[i].equals("-driver")) 
                    driver = args[++i];
                else if (args[i].equals("-user")) 
                    user = args[++i];
                else if (args[i].equals("-password")) 
                    password = args[++i];
                else if (args[i].equals("-file")) 
                    file = args[++i];
                else if (args[i].equals("-table")) 
                    table = args[++i];
            }
        }
        
        if((url == null)||(driver == null)||(file == null))
        {
            System.out.println("usage: DBBackup"
                                +" -url url"
                                +" -driver driverClassName"
                                +" [-user user]"
                                +" [-password pass]"
                                +" -file XMLFileName"
                                +" [-table tableName]");
                                
            System.exit(0);
        }
        
        backup = new DBBackup(url,driver,user,password,file,table);
        backup.performBackup();
        backup.close();
    }
}