dbrestore.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.*; 
import org.w3c.dom.*;
import javax.xml.parsers.*;

public class DBRestore extends Object
{
    Connection connection;
    Statement statement;
    String xmlFile;
    boolean deleteExisting;
    boolean verbose;
    
    public DBRestore(String url, String driverName,
                       String user, String passwd,
                       String file, boolean delete,boolean verb)
    {
        try
        {
            //load the driver
            Class.forName(driverName);

            connection = 
                    DriverManager.getConnection(url, user, passwd);
                    
            statement = connection.createStatement();
            
            xmlFile = file;
            deleteExisting = delete;
            verbose = verb;
            if(verbose) System.out.println("Connected to "+url);
        }
        catch (Exception exp)
        {
            System.out.println("Error connecting: "+exp);
        }    
     }

    public void performRestore()
    {
        DocumentBuilder docBuilder;
        Document doc;
        Node dbElement;
        Node curTable,curRow,curField;
        NodeList tables;
        int i,maxTables;
        NodeList rows;
        int j,maxRows;
        NodeList fields;
        int k,maxFields;
        String tableName;
        String rowName;
        String fieldName,fieldType;
        String data;
        StringBuffer sql = new StringBuffer();
        boolean gotOne;
        
        try
        {  
            docBuilder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
          
            doc = docBuilder.parse(xmlFile);
            
            //set dbElement to the root database element
            dbElement = doc.getDocumentElement();
            
            //get the table elements
            tables = dbElement.getChildNodes();
            maxTables = tables.getLength();
            
            for(i=0;i<maxTables;i++)
            {
                curTable = tables.item(i);
                
                //skip any text elements surrounding tables
                if(!"TABLE".equals(curTable.getNodeName())) continue;
                
                tableName =
                    curTable.getAttributes().getNamedItem("NAME").getNodeValue();

                if(verbose) System.out.println("Restoring: "+tableName);
                
                if(deleteExisting)
                {
                    if(verbose) System.out.println("\tDeleting: "+tableName);
                    statement.executeUpdate("delete from "+tableName);
                }
                
                rows = curTable.getChildNodes();
                maxRows = rows.getLength();
                
                for(j=0;j<maxRows;j++)
                {  
                    curRow = rows.item(j);
                    if(!"ROW".equals(curRow.getNodeName())) continue;
                
                    sql.setLength(0);
                    sql.append("insert into ");
                    sql.append(tableName);
                    sql.append(" (");
                    
                    fields = curRow.getChildNodes();
                    maxFields = fields.getLength();
                    
                    gotOne = false;
                    
                    //Build the column names for the insert statement
                    for(k=0;k<maxFields;k++)
                    {
                        curField = fields.item(k);
                    
                        fieldType = 
                            curField.getNodeName();
                            
                        if(!"NUMERIC".equals(fieldType)
                                &&!"TEXT".equals(fieldType)) continue;
                                
                        if(curField.getFirstChild()==null) continue;
                        
                        if(gotOne) sql.append(",");
                    
                        gotOne = true;
                        
                        fieldName = 
                            curField.getAttributes().getNamedItem("NAME").getNodeValue();
                        
                        sql.append(fieldName);
                    }
                    
                    sql.append(") values (");
                    
                    gotOne = false;
                    
                    //Build the column values for the insert statement
                    for(k=0;k<maxFields;k++)
                    {
                        curField = fields.item(k);
                    
                        fieldType = 
                            curField.getNodeName();
                        
                        if(!"NUMERIC".equals(fieldType)
                                &&!"TEXT".equals(fieldType)) continue;
                        
                        //Skip blank tags
                        if(curField.getFirstChild()==null) continue;
                        
                        if(gotOne) sql.append(",");
                    
                        gotOne = true;
                        data = null;
                        
                        if("TEXT".equals(fieldType))
                        {
                            data = curField.getFirstChild().getNodeValue();
                                
                            if(data == null) data = "";
                            else
                            {
                                data = URLDecoder.decode(data);
                            
                                data = StringUtils.escape(data);
                            }
                            
                            sql.append("\'");
                            sql.append(data);
                            sql.append("\'");
                        }
                        else if("NUMERIC".equals(fieldType))
                        {
                            sql.append(curField.getFirstChild().getNodeValue());
                        }
                    }
                    
                    sql.append(")");
                    
                    if(verbose) System.out.println("\t"+sql.toString());
                    statement.executeUpdate(sql.toString());
                }
            }
        }
        catch (Exception exp)
        {
            System.out.println("Error performing backup: "+exp);
            exp.printStackTrace();
        }    
    }

    public void close()
    {
        try
        {
            statement.close();
            connection.close();
            if(verbose) System.out.println("Disconnected.");
        }
        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;
        boolean doDelete=false;
        boolean doVerbose=false;
        DBRestore restore;
        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("-D")) 
                    doDelete = true;
                else if (args[i].equals("-verbose")) 
                    doVerbose = true;
            }
        }
        
        if((url == null)||(driver == null)||(file == null))
        {
            System.out.println("usage: DBRestore"
                                +" -url url"
                                +" -driver driverClassName"
                                +" [-user user]"
                                +" [-password pass]"
                                +" -file XMLFileName"
                                +" [-D]"
                                +" [-verbose]");
                                
            System.exit(0);
        }
        
        restore = new DBRestore(url,driver,user,password,file,doDelete,doVerbose);
        restore.performRestore();
        restore.close();
    }
}