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Inserting records into Berkeley DB with Java

开发者 https://www.devze.com 2022-12-28 02:03 出处:网络
I can\'t seem to find sample code for constructing a Berkeley DB in Java and inserting records into it. Any samples? And I do not mean the Berkeley DB Java Edition e开发者_如何学Pythonither.http://www

I can't seem to find sample code for constructing a Berkeley DB in Java and inserting records into it. Any samples? And I do not mean the Berkeley DB Java Edition e开发者_如何学Pythonither.


http://www.oracle.com/technology/documentation/berkeley-db/db/programmer_reference/BDB_Prog_Reference.pdf Chapter 5

If you download db-5.0.21.NC.zip you will see plenty of samples. Here is one that seems to do what you want

/*-
 * See the file LICENSE for redistribution information.
 *
 * Copyright (c) 2004, 2010 Oracle and/or its affiliates.  All rights reserved.
 *
 * $Id$ 
 */

// File: ExampleDatabaseLoad.java

package db.GettingStarted;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;
import java.util.StringTokenizer;
import java.util.Vector;

import com.sleepycat.bind.EntryBinding;
import com.sleepycat.bind.serial.SerialBinding;
import com.sleepycat.bind.tuple.TupleBinding;
import com.sleepycat.db.DatabaseEntry;
import com.sleepycat.db.DatabaseException;

public class ExampleDatabaseLoad {

    private static String myDbsPath = "./";
    private static File inventoryFile = new File("./inventory.txt");
    private static File vendorsFile = new File("./vendors.txt");

    // DatabaseEntries used for loading records
    private static DatabaseEntry theKey = new DatabaseEntry();
    private static DatabaseEntry theData = new DatabaseEntry();

    // Encapsulates the databases.
    private static MyDbs myDbs = new MyDbs();

    private static void usage() {
        System.out.println("ExampleDatabaseLoad [-h <database home>]");
        System.out.println("      [-i <inventory file>] [-v <vendors file>]");
        System.exit(-1);
    }


    public static void main(String args[]) {
        ExampleDatabaseLoad edl = new ExampleDatabaseLoad();
        try {
            edl.run(args);
        } catch (DatabaseException dbe) {
            System.err.println("ExampleDatabaseLoad: " + dbe.toString());
            dbe.printStackTrace();
        } catch (Exception e) {
            System.out.println("Exception: " + e.toString());
            e.printStackTrace();
        } finally {
            myDbs.close();
        }
        System.out.println("All done.");
    }


    private void run(String args[])
        throws DatabaseException {
        // Parse the arguments list
        parseArgs(args);

        myDbs.setup(myDbsPath);

        System.out.println("loading vendors db....");
        loadVendorsDb();

        System.out.println("loading inventory db....");
        loadInventoryDb();
    }


    private void loadVendorsDb()
            throws DatabaseException {

        // loadFile opens a flat-text file that contains our data
        // and loads it into a list for us to work with. The integer
        // parameter represents the number of fields expected in the
        // file.
        List vendors = loadFile(vendorsFile, 8);

        // Now load the data into the database. The vendor's name is the
        // key, and the data is a Vendor class object.

        // Need a serial binding for the data
        EntryBinding dataBinding =
            new SerialBinding(myDbs.getClassCatalog(), Vendor.class);

        for (int i = 0; i < vendors.size(); i++) {
            String[] sArray = (String[])vendors.get(i);
            Vendor theVendor = new Vendor();
            theVendor.setVendorName(sArray[0]);
            theVendor.setAddress(sArray[1]);
            theVendor.setCity(sArray[2]);
            theVendor.setState(sArray[3]);
            theVendor.setZipcode(sArray[4]);
            theVendor.setBusinessPhoneNumber(sArray[5]);
            theVendor.setRepName(sArray[6]);
            theVendor.setRepPhoneNumber(sArray[7]);

            // The key is the vendor's name.
            // ASSUMES THE VENDOR'S NAME IS UNIQUE!
            String vendorName = theVendor.getVendorName();
            try {
                theKey = new DatabaseEntry(vendorName.getBytes("UTF-8"));
            } catch (IOException willNeverOccur) {}

            // Convert the Vendor object to a DatabaseEntry object
            // using our SerialBinding
            dataBinding.objectToEntry(theVendor, theData);

            // Put it in the database.
            myDbs.getVendorDB().put(null, theKey, theData);
        }
    }


    private void loadInventoryDb()
        throws DatabaseException {

        // loadFile opens a flat-text file that contains our data
        // and loads it into a list for us to work with. The integer
        // parameter represents the number of fields expected in the
        // file.
        List inventoryArray = loadFile(inventoryFile, 6);

        // Now load the data into the database. The item's sku is the
        // key, and the data is an Inventory class object.

        // Need a tuple binding for the Inventory class.
        TupleBinding inventoryBinding = new InventoryBinding();

        for (int i = 0; i < inventoryArray.size(); i++) {
            String[] sArray = (String[])inventoryArray.get(i);
            String sku = sArray[1];
            try {
                theKey = new DatabaseEntry(sku.getBytes("UTF-8"));
            } catch (IOException willNeverOccur) {}

            Inventory theInventory = new Inventory();
            theInventory.setItemName(sArray[0]);
            theInventory.setSku(sArray[1]);
            theInventory.setVendorPrice((new Float(sArray[2])).floatValue());
            theInventory.setVendorInventory((new Integer(sArray[3])).intValue());
            theInventory.setCategory(sArray[4]);
            theInventory.setVendor(sArray[5]);

            // Place the Vendor object on the DatabaseEntry object using our
            // the tuple binding we implemented in InventoryBinding.java
            inventoryBinding.objectToEntry(theInventory, theData);

            // Put it in the database. Note that this causes our secondary database
            // to be automatically updated for us.
            myDbs.getInventoryDB().put(null, theKey, theData);
        }
    }


    private static void parseArgs(String args[]) {
        for(int i = 0; i < args.length; ++i) {
            if (args[i].startsWith("-")) {
                switch(args[i].charAt(1)) {
                  case 'h':
                    myDbsPath = new String(args[++i]);
                    break;
                  case 'i':
                    inventoryFile = new File(args[++i]);
                    break;
                  case 'v':
                    vendorsFile = new File(args[++i]);
                    break;
                  default:
                    usage();
                }
            }
        }
    }


    private List loadFile(File theFile, int numFields) {
        List records = new ArrayList();
        try {
            String theLine = null;
            FileInputStream fis = new FileInputStream(theFile);
            BufferedReader br = new BufferedReader(new InputStreamReader(fis));
            while((theLine=br.readLine()) != null) {
                String[] theLineArray = splitString(theLine, "#");
                if (theLineArray.length != numFields) {
                    System.out.println("Malformed line found in " + theFile.getPath());
                    System.out.println("Line was: '" + theLine);
                    System.out.println("length found was: " + theLineArray.length);
                    System.exit(-1);
                }
                records.add(theLineArray);
            }
            fis.close();
        } catch (FileNotFoundException e) {
            System.err.println(theFile.getPath() + " does not exist.");
            e.printStackTrace();
            usage();
        } catch (IOException e)  {
            System.err.println("IO Exception: " + e.toString());
            e.printStackTrace();
            System.exit(-1);
        }
        return records;
    }


    private static String[] splitString(String s, String delimiter) {
        Vector resultVector = new Vector();
        StringTokenizer tokenizer = new StringTokenizer(s, delimiter);
        while (tokenizer.hasMoreTokens())
            resultVector.add(tokenizer.nextToken());
        String[] resultArray = new String[resultVector.size()];
        resultVector.copyInto(resultArray);
        return resultArray;
    }


    protected ExampleDatabaseLoad() {}
}


There are a number of good Getting Started Guides for Oracle Berkeley DB Java Edition. They are included in the documentation set. You'll find example code in the documentation. If you're new to Oracle Berkeley DB Java Edition that's the right place to start. There are other examples in the download package as well.

I'm the product manager for Oracle Berkeley DB, I hope this addressed your question. If not please let me know how else I can help you.

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