Oracle Berkeley DB Java Edition – Gokhan Atil’s Blog

I was searching NoSQL databases and see that Oracle provides a NoSQL database called Berkeley DB. I examined it and wrote a blog to give quick tips to start Java Edition of Berkeley DB. This blog was published in Turkish, about 1 year ago. I’ve decided to translate (in fact, re-write) and publish it in English, and this is what you are reading now.

Berkeley DB is a high-performance embedded database originated at the University of California, Berkeley. It’s fast, reliable and used in several applications such as Evolution (email client), OpenLDAP, RPM (The RPM Package Manager) and Postfix (MTA). In contrast to most other database systems, Berkeley DB provides relatively simple data access services. Berkeley DB databases are B+Trees (like indexes in Oracle RDBMS) and can store only key/value pairs (there are no columns or tables). The keys and values are byte arrays. Databases are stored as files within a single directory which is called “environment”.

There are three versions of Berkeley DB:

Berkeley DB (the traditional database, written in C)
Berkeley DB Java Edition (native Java version)
Berkeley DB XML (for storing XML documents)

As a hobbyist Java programmer, I prefer Berkeley DB Java Edition (JE). Berkeley DB JE supports almost all features of traditional Berkeley DB such as replication, hot-backups, ACID and transactions. It is written in pure Java so it’s platform-independent.

Berkeley DB JE provides two interfaces:

Traditional Berkeley DB API (with DB data abstraction of key/value pairs)
Direct Persistence Layer (DPL) which contains “Plain Old Java Objects” (POJO)

Because I’m an old-school (ex)programmer, I’ll show how to use the traditional Berkeley DB API. Traditional Berkeley DB API will help you understand how Berkeley DB works.

Let’s start by downloading the Berkeley DB from Oracle website:

http://www.oracle.com/technetwork/database/berkeleydb/downloads/index.html

After you download the file (je-x.x.x.tar.gz/zip), extract it. You’ll find the required JAR file (je-x.x.x.jar) in “lib” folder. You can add it to your Java project and start using Berkeley DB Java Edition.

Berkeley DB stored the datafiles in a folder. We define this folder as an environment object:

public static void main(String[] args) {

    try {
        // create a configuration for DB environment
        EnvironmentConfig envConf = new EnvironmentConfig();
        // environment will be created if not exists
        envConf.setAllowCreate(true);

        // open/create the DB environment using config
        Environment dbEnv = new Environment(
                new File("/home/gokhan/berkeleydb"), envConf);

    } catch (DatabaseException dbe) {
        System.out.println("Error :" + dbe.getMessage() );
    }
}

public static void main(String[] args) {

try {

// create a configuration for DB environment

EnvironmentConfig envConf = new EnvironmentConfig();

// environment will be created if not exists

envConf.setAllowCreate(true);

// open/create the DB environment using config

Environment dbEnv = new Environment(

new File("/home/gokhan/berkeleydb"), envConf);

} catch (DatabaseException dbe) {

System.out.println("Error :" + dbe.getMessage() );

}

Before running the above code, we should be sure that this folder ( “/home/gokhan/berkeleydb” ) exists and our user have required privileges to access it. After you run the code, you’ll see that Berkeley DB created the base files in this folder:

gokhan@exodus:~/berkeleydb$ ls -lh

total 4.0K
-rw-r--r-- 1 gokhan gokhan 1.6K 2011-09-12 21:11 00000000.jdb
-rw-r--r-- 1 gokhan gokhan    0 2011-09-10 02:12 je.info.0
-rw-r--r-- 1 gokhan gokhan    0 2011-09-12 21:11 je.info.0.lck
-rw-r--r-- 1 gokhan gokhan    0 2011-09-10 02:12 je.lck

gokhan@exodus:~/berkeleydb$ ls -lh

total 4.0K

-rw-r--r-- 1 gokhan gokhan 1.6K 2011-09-12 21:11 00000000.jdb

-rw-r--r-- 1 gokhan gokhan 0 2011-09-10 02:12 je.info.0

-rw-r--r-- 1 gokhan gokhan 0 2011-09-12 21:11 je.info.0.lck

-rw-r--r-- 1 gokhan gokhan 0 2011-09-10 02:12 je.lck

The same code can also be used for “opening” an existing environment. Now we can create (or open) our database in the environment we defined:

// create a configuration for DB
DatabaseConfig dbConf = new DatabaseConfig();
// db will be created if not exits
dbConf.setAllowCreate(true);

// create/open testDB using config
Database testDB = dbEnv.openDatabase(null, "testDB", dbConf);

// create a configuration for DB

DatabaseConfig dbConf = new DatabaseConfig();

// db will be created if not exits

dbConf.setAllowCreate(true);

// create/open testDB using config

Database testDB = dbEnv.openDatabase(null, "testDB", dbConf);

As I said Berkeley DB can store key/value pairs. We will use DatabaseEntry object to store key/value pairs. The following code will insert “1” as key and “GOKHAN ATIL” as data:

// create a configuration for DB
DatabaseConfig dbConf = new DatabaseConfig();
// db will be created if not exits
dbConf.setAllowCreate(true);

// assign 1 to key
IntegerBinding.intToEntry(1, key);
// assign my name to data
StringBinding.stringToEntry("GOKHAN ATIL", data);

// insert key/value pair to database
testDB.put(null, key, data);

// create a configuration for DB

DatabaseConfig dbConf = new DatabaseConfig();

// db will be created if not exits

dbConf.setAllowCreate(true);

// assign 1 to key

IntegerBinding.intToEntry(1, key);

// assign my name to data

StringBinding.stringToEntry("GOKHAN ATIL", data);

// insert key/value pair to database

testDB.put(null, key, data);

As you can see, we convert our variables to entries and then use Database object to store them. The “put” method of the Database object is used to insert data:

// sequence will be created if not exits
SequenceConfig seqConf = new SequenceConfig();
seqConf.setAllowCreate(true);

// give a name to sequence
DatabaseEntry entMySeq = new DatabaseEntry();
StringBinding.stringToEntry("MY_SEQ", entMySeq);

// open (or create) sequence
Sequence mySeq = testDB.openSequence(null, entMySeq, seqConf);

// read a number from sequence, set key
IntegerBinding.intToEntry( (int)mySeq.get(null, 1), key);

// set my name as data
StringBinding.stringToEntry("GOKHAN ATIL", data);

// insert (or update) key/value pair to database
testDB.put(null, key, data);

// sequence will be created if not exits

SequenceConfig seqConf = new SequenceConfig();

seqConf.setAllowCreate(true);

// give a name to sequence

DatabaseEntry entMySeq = new DatabaseEntry();

StringBinding.stringToEntry("MY_SEQ", entMySeq);

// open (or create) sequence

Sequence mySeq = testDB.openSequence(null, entMySeq, seqConf);

// read a number from sequence, set key

IntegerBinding.intToEntry( (int)mySeq.get(null, 1), key);

// set my name as data

StringBinding.stringToEntry("GOKHAN ATIL", data);

// insert (or update) key/value pair to database

testDB.put(null, key, data);

If the key already exists in the database and no duplicate records are allowed (default), the “put” method will update the existing pair. To read a pair, we need to use “get” method:

// read from database
testDB.get(null, key, data, null);

// display key/value pair
System.out.println("Key  :" + IntegerBinding.entryToInt(key));
System.out.println("Data :" + StringBinding.entryToString(data));

// read from database

testDB.get(null, key, data, null);

// display key/value pair

System.out.println("Key :" + IntegerBinding.entryToInt(key));

System.out.println("Data :" + StringBinding.entryToString(data));

To delete records, we can use “delete” method:

testDB.delete(null, key);

1	testDB.delete(null, key);

Now I’ll combine these functions and write a sample application to generate 500.000 dummy records, insert them into the database and then get a random record:

package berkeleydemo;

import com.sleepycat.bind.tuple.IntegerBinding;
import com.sleepycat.bind.tuple.StringBinding;
import com.sleepycat.je.Database;
import com.sleepycat.je.DatabaseConfig;
import com.sleepycat.je.DatabaseEntry;
import com.sleepycat.je.DatabaseException;
import com.sleepycat.je.Environment;
import com.sleepycat.je.EnvironmentConfig;
import com.sleepycat.je.OperationStatus;
import com.sleepycat.je.Sequence;
import com.sleepycat.je.SequenceConfig;
import java.io.File;
import java.text.DecimalFormat;
import java.text.NumberFormat;
import java.util.Random;

/**
 * Author: Gokhan Atil 
 * Web: http://www.gokhanatil.com
 */
public class BerkeleyDemo {

  public static void main(String[] args) {

    try {
      // create a configuration for DB environment
      EnvironmentConfig envConf = new EnvironmentConfig();
      // environment will be created if not exists
      envConf.setAllowCreate(true);

      // open/create the DB environment using config
      Environment dbEnv = new Environment(
              new File("d:\\berkeleydb"), envConf);

      // create a configuration for DB
      DatabaseConfig dbConf = new DatabaseConfig();
      // db will be created if not exits
      dbConf.setAllowCreate(true);

      // create/open testDB using config
      Database testDB = dbEnv.openDatabase(null, "testDB", dbConf);

      // key
      DatabaseEntry key = new DatabaseEntry();
      // data
      DatabaseEntry data = new DatabaseEntry();

      // sequence will be created if not exits
      SequenceConfig seqConf = new SequenceConfig();
      seqConf.setAllowCreate(true);

      // give a name to sequence
      DatabaseEntry entMySeq = new DatabaseEntry();
      StringBinding.stringToEntry("MY_SEQ", entMySeq);

      // open (or create) sequence
      Sequence mySeq = testDB.openSequence(null, entMySeq, seqConf);

      // will use it for formatting numbers
      NumberFormat formatter = new DecimalFormat("000000");

      // 500.000 records
      for (int i = 0; i < 500000; i++) {

        // read a number from sequence, set key 
        // yes I could just use "i" but I wanted to test sequences
        IntegerBinding.intToEntry((int) mySeq.get(null, 1), key);

        // format and assign "i" to data
        StringBinding.stringToEntry("N#" + formatter.format(i), data);

        // insert key/value pair to database
        testDB.put(null, key, data);

      }
      // empty the data
      StringBinding.stringToEntry("", data);

      // random generator for generating random number
      Random generator = new Random();

      // assing a random number to key
      IntegerBinding.intToEntry((int) generator.nextInt(500000), key);

      // read from database
      if ((testDB.get(null, key, data, null)
              == OperationStatus.SUCCESS)) {

        // display key/value pair
        System.out.println("Key  :" + IntegerBinding.entryToInt(key));
        System.out.println("Data :" + StringBinding.entryToString(data));

      } else {
        System.out.println("Couldn't find");
      }

      // important: do not forget to close them!
      mySeq.close();
      testDB.close();
      dbEnv.close();

    } catch (DatabaseException dbe) {
      System.out.println("Error :" + dbe.getMessage());
    }
  }
}

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package berkeleydemo;

import com.sleepycat.bind.tuple.IntegerBinding;

import com.sleepycat.bind.tuple.StringBinding;

import com.sleepycat.je.Database;

import com.sleepycat.je.DatabaseConfig;

import com.sleepycat.je.DatabaseEntry;

import com.sleepycat.je.DatabaseException;

import com.sleepycat.je.Environment;

import com.sleepycat.je.EnvironmentConfig;

import com.sleepycat.je.OperationStatus;

import com.sleepycat.je.Sequence;

import com.sleepycat.je.SequenceConfig;

import java.io.File;

import java.text.DecimalFormat;

import java.text.NumberFormat;

import java.util.Random;

/**

* Author: Gokhan Atil

* Web: http://www.gokhanatil.com

public class BerkeleyDemo {

public static void main(String[] args) {

try {

// create a configuration for DB environment

EnvironmentConfig envConf = new EnvironmentConfig();

// environment will be created if not exists

envConf.setAllowCreate(true);

// open/create the DB environment using config

Environment dbEnv = new Environment(

new File("d:\\berkeleydb"), envConf);

// create a configuration for DB

DatabaseConfig dbConf = new DatabaseConfig();

// db will be created if not exits

dbConf.setAllowCreate(true);

// create/open testDB using config

Database testDB = dbEnv.openDatabase(null, "testDB", dbConf);

// key

DatabaseEntry key = new DatabaseEntry();

// data

DatabaseEntry data = new DatabaseEntry();

// sequence will be created if not exits

SequenceConfig seqConf = new SequenceConfig();

seqConf.setAllowCreate(true);

// give a name to sequence

DatabaseEntry entMySeq = new DatabaseEntry();

StringBinding.stringToEntry("MY_SEQ", entMySeq);

// open (or create) sequence

Sequence mySeq = testDB.openSequence(null, entMySeq, seqConf);

// will use it for formatting numbers

NumberFormat formatter = new DecimalFormat("000000");

// 500.000 records

for (int i = 0; i < 500000; i++) {

// read a number from sequence, set key

// yes I could just use "i" but I wanted to test sequences

IntegerBinding.intToEntry((int) mySeq.get(null, 1), key);

// format and assign "i" to data

StringBinding.stringToEntry("N#" + formatter.format(i), data);

// insert key/value pair to database

testDB.put(null, key, data);

}

// empty the data

StringBinding.stringToEntry("", data);

// random generator for generating random number

Random generator = new Random();

// assing a random number to key

IntegerBinding.intToEntry((int) generator.nextInt(500000), key);

// read from database

if ((testDB.get(null, key, data, null)

== OperationStatus.SUCCESS)) {

// display key/value pair

System.out.println("Key :" + IntegerBinding.entryToInt(key));

System.out.println("Data :" + StringBinding.entryToString(data));

} else {

System.out.println("Couldn't find");

}

// important: do not forget to close them!

mySeq.close();

testDB.close();

dbEnv.close();

} catch (DatabaseException dbe) {

System.out.println("Error :" + dbe.getMessage());

}

As you see, Berkeley DB does not have columns, so how can we store a data consisting of multiple columns? We’ll solve this by using TupleInput and TupleOutput objects. Let’s say I want to store name, email and department of employees. First I define an object containing objectToEntry and entryToObject for employee record:

package berkeleydemo;

import com.sleepycat.bind.tuple.TupleBinding;
import com.sleepycat.bind.tuple.TupleInput;
import com.sleepycat.bind.tuple.TupleOutput;
import com.sleepycat.je.DatabaseEntry;

public class Employee {

  public String getDepartment() {
    return Department;
  }

  public void setDepartment(String Department) {
    this.Department = Department;
  }

  public String getEmail() {
    return Email;
  }

  public void setEmail(String Email) {
    this.Email = Email;
  }

  public String getName() {
    return Name;
  }

  public void setName(String Name) {
    this.Name = Name;
  }

  public Employee(String Name, String Email, String Department) {
    this.Name = Name;
    this.Email = Email;
    this.Department = Department;
  }

  public Employee() {
  }

  // set name, email, dept
  public void setEmployee(String Name, String Email, String Department) {
    this.Name = Name;
    this.Email = Email;
    this.Department = Department;
  }

  // display name, email, dept information
  public void Display() {

    System.out.println("Name...: " + Name);
    System.out.println("Email..: " + Email);
    System.out.println("Dept...: " + Department);
  }

  // convert object to entry
  public DatabaseEntry objectToEntry() {

    TupleOutput output = new TupleOutput();

    DatabaseEntry entry = new DatabaseEntry();

    // write name, email and department to tuple
    output.writeString(getName());
    output.writeString(getEmail());
    output.writeString(getDepartment());

    TupleBinding.outputToEntry(output, entry);

    return entry;
  }

  // convert entry to object
  public void entryToObject(DatabaseEntry entry) {

    TupleInput input = TupleBinding.entryToInput(entry);

    // set name, email and department
    setName(input.readString());
    setEmail(input.readString());
    setDepartment(input.readString());
  }

  private String Name;
  private String Email;
  private String Department;

}

package berkeleydemo;

import com.sleepycat.bind.tuple.TupleBinding;

import com.sleepycat.bind.tuple.TupleInput;

import com.sleepycat.bind.tuple.TupleOutput;

import com.sleepycat.je.DatabaseEntry;

public class Employee {

public String getDepartment() {

return Department;

}

public void setDepartment(String Department) {

this.Department = Department;

}

public String getEmail() {

return Email;

}

public void setEmail(String Email) {

this.Email = Email;

}

public String getName() {

return Name;

}

public void setName(String Name) {

this.Name = Name;

}

public Employee(String Name, String Email, String Department) {

this.Name = Name;

this.Email = Email;

this.Department = Department;

}

public Employee() {

}

// set name, email, dept

public void setEmployee(String Name, String Email, String Department) {

this.Name = Name;

this.Email = Email;

this.Department = Department;

}

// display name, email, dept information

public void Display() {

System.out.println("Name...: " + Name);

System.out.println("Email..: " + Email);

System.out.println("Dept...: " + Department);

}

// convert object to entry

public DatabaseEntry objectToEntry() {

TupleOutput output = new TupleOutput();

DatabaseEntry entry = new DatabaseEntry();

// write name, email and department to tuple

output.writeString(getName());

output.writeString(getEmail());

output.writeString(getDepartment());

TupleBinding.outputToEntry(output, entry);

return entry;

}

// convert entry to object

public void entryToObject(DatabaseEntry entry) {

TupleInput input = TupleBinding.entryToInput(entry);

// set name, email and department

setName(input.readString());

setEmail(input.readString());

setDepartment(input.readString());

}

private String Name;

private String Email;

private String Department;

}

Let’s insert sample records and then try to find (and read) them:

package berkeleydemo;

import com.sleepycat.bind.tuple.IntegerBinding;
import com.sleepycat.bind.tuple.StringBinding;
import com.sleepycat.je.Database;
import com.sleepycat.je.DatabaseConfig;
import com.sleepycat.je.DatabaseEntry;
import com.sleepycat.je.DatabaseException;
import com.sleepycat.je.Environment;
import com.sleepycat.je.EnvironmentConfig;
import com.sleepycat.je.OperationStatus;
import java.io.File;

/**
 * Author: Gokhan Atil 
 * Web: http://www.gokhanatil.com
 */
public class BerkeleyDemo {

  public static void main(String[] args) {

    try {
      // create a configuration for DB environment
      EnvironmentConfig envConf = new EnvironmentConfig();
      // environment will be created if not exists
      envConf.setAllowCreate(true);

      // open/create the DB environment using config
      Environment dbEnv = new Environment(
              new File("d:\\berkeleydb"), envConf);

      // create a configuration for DB
      DatabaseConfig dbConf = new DatabaseConfig();
      // db will be created if not exits
      dbConf.setAllowCreate(true);

      // create/open testDB using config
      Database testDB = dbEnv.openDatabase(null, "testDB", dbConf);

      // key
      DatabaseEntry key = new DatabaseEntry();
      // data
      DatabaseEntry data = new DatabaseEntry();

      Employee emp = new Employee( "Gokhan", "gokhan@gokhanatil", "IT");

      // assign 1 to key
      IntegerBinding.intToEntry(1, key);
      // insert into database
      testDB.put(null, key, emp.objectToEntry());

      // assign 2 to key
      IntegerBinding.intToEntry(2, key);
      // assign new values
      emp.setEmployee("Jack", "jack@nowhere", "SALES");
      // insert into database
      testDB.put(null, key, emp.objectToEntry());

      // assign 3 to key
      IntegerBinding.intToEntry(3, key);
      // assign new values
      emp.setEmployee("Lee", "jet@lee", "BILLING");
      // insert into database
      testDB.put(null, key, emp.objectToEntry());

      // assign 2 to key
      IntegerBinding.intToEntry(2, key);      

      // read from database (find key=2)
      if ((testDB.get(null, key, data, null)
              == OperationStatus.SUCCESS)) {

        // assign new values from dataentry to emp
        emp.entryToObject(data);
        // display emp
        emp.Display();

      } else {
        System.out.println("Couldn't find");
      }

      // important: do not forget to close them!
      testDB.close();
      dbEnv.close();

    } catch (DatabaseException dbe) {
      System.out.println("Error :" + dbe.getMessage());
    }
  }
}

package berkeleydemo;

import com.sleepycat.bind.tuple.IntegerBinding;

import com.sleepycat.bind.tuple.StringBinding;

import com.sleepycat.je.Database;

import com.sleepycat.je.DatabaseConfig;

import com.sleepycat.je.DatabaseEntry;

import com.sleepycat.je.DatabaseException;

import com.sleepycat.je.Environment;

import com.sleepycat.je.EnvironmentConfig;

import com.sleepycat.je.OperationStatus;

import java.io.File;

/**

* Author: Gokhan Atil

* Web: http://www.gokhanatil.com

public class BerkeleyDemo {

public static void main(String[] args) {

try {

// create a configuration for DB environment

EnvironmentConfig envConf = new EnvironmentConfig();

// environment will be created if not exists

envConf.setAllowCreate(true);

// open/create the DB environment using config

Environment dbEnv = new Environment(

new File("d:\\berkeleydb"), envConf);

// create a configuration for DB

DatabaseConfig dbConf = new DatabaseConfig();

// db will be created if not exits

dbConf.setAllowCreate(true);

// create/open testDB using config

Database testDB = dbEnv.openDatabase(null, "testDB", dbConf);

// key

DatabaseEntry key = new DatabaseEntry();

// data

DatabaseEntry data = new DatabaseEntry();

Employee emp = new Employee( "Gokhan", "gokhan@gokhanatil", "IT");

// assign 1 to key

IntegerBinding.intToEntry(1, key);

// insert into database

testDB.put(null, key, emp.objectToEntry());

// assign 2 to key

IntegerBinding.intToEntry(2, key);

// assign new values

emp.setEmployee("Jack", "jack@nowhere", "SALES");

// insert into database

testDB.put(null, key, emp.objectToEntry());

// assign 3 to key

IntegerBinding.intToEntry(3, key);

// assign new values

emp.setEmployee("Lee", "jet@lee", "BILLING");

// insert into database

testDB.put(null, key, emp.objectToEntry());

// assign 2 to key

IntegerBinding.intToEntry(2, key);

// read from database (find key=2)

if ((testDB.get(null, key, data, null)

== OperationStatus.SUCCESS)) {

// assign new values from dataentry to emp

emp.entryToObject(data);

// display emp

emp.Display();

} else {

System.out.println("Couldn't find");

}

// important: do not forget to close them!

testDB.close();

dbEnv.close();

} catch (DatabaseException dbe) {

System.out.println("Error :" + dbe.getMessage());

}

You can find official documents for Berkeley DB Java Edition at Oracle website:

http://www.oracle.com/technetwork/database/berkeleydb/documentation/index-160410.html

This is just a quick start for Berkeley DB Java Edition. What’s next? Secondary databases, Direct Persistence Layer, cursors, dealing with non-unique keys, transactions… I do not promise but I’ll try to write about these topics in future.

Please share

15 Comments

rick

November 6, 2012 Reply

Berkely DB (transactional) has easy corruptibility and recovery is very error prone & tedious and not full proof.

We tried using in our financial application server it frequently gets corrupted and downtime is significant.Basically for mission critical application where data and availability is critical berkely db is strict no no.
- Gokhan Atil
  
  November 8, 2012
  
  Rick, thanks for sharing your experience with it.
Dave Joyce

December 13, 2012 Reply

Gokhan:

Thank you for this post! After reading through the Oracle docs, this really helped me get started with Berkeley DB, especially your examples of TupleOutput and TupleInput from the Bind API.
- Gokhan Atil
  
  December 13, 2012
  
  Dave, you are welcome. I’m happy to hear that it helped you.
Eric Ford

May 15, 2013 Reply

I’m just getting started with BDB JE (v5.0.73) and immediately ran into trouble with the Environment. Apparently, the Environment class (in this version) does NOT support creating the file location. It throws an IllegalArgumentException in the FileManager class if the file does not already exist, regardless of the value input for “setAllowCreate”.
- Eric Ford
  
  May 15, 2013
  
  The setAllowCreate parameter governs whether the files generated by BDB may be created – not the environment path itself.
- Gokhan Atil
  
  May 16, 2013
  
  Yes, it seems you found the answer by yourself. Thanks for sharing.
Santhana

June 27, 2013 Reply

Hi,

It’s a great post. The example is very clean and got me through. I have a couple of questions.

Can we use Berkley DB in web applications?

And if we can use it, do we still need to pay the licensing fees?
Srimantula

November 13, 2013 Reply

Hi,

it s a very good article.

could you please write a little bit how to view an existed.jdb file

or how to get the values of an existed .jdb file

thanking you
keshan

April 8, 2014 Reply

Hi, This is a great blog. I’m using @Primary Key(sequence = “ID”) to auto increment the primary key value. But after every database inserted it increment by 100. As a example 1, 101, 201 , 301 etc. What is wrong, is there any parameter to specify. Please Help me.

Thank you
Random

July 5, 2016 Reply

Hey,

Can u please tell me how to handle images in the database.

Thanks.
- JustLikeThat
  
  November 22, 2016
  
  read the image as byte array
  
  byte[] sBytes = readImageAsByteArray(sourceImage);
  
  and create a wrapper class as follows…
  
  public class Image implements Serializable { private int imageId; private byte[] imageBytes;
  public int getImageId() { return imageId; } public void setImageId(int imageId) { this.imageId = imageId; } public byte[] getImageBytes() { return imageBytes; } public void setImageBytes(byte[] imageBytes) { this.imageBytes = imageBytes; } public DatabaseEntry objectToEntry() { //your wrapper class fields... }
  public void entryToObject(DatabaseEntry entry) { //your wrapper class fields... } }
  
  and by using the following code you can persist your images as byte array…
  
  // key DatabaseEntry key = new DatabaseEntry(); // data DatabaseEntry data = new DatabaseEntry();
  Image img = new Image (1, sBytes)
  // assign 1 to key IntegerBinding.intToEntry(1, key); // insert into database testDB.put(null, key, img.objectToEntry());
zeroual

February 2, 2017 Reply

Merci beaucoup pour cette explication détaillée
vijay

April 1, 2017 Reply

I am vijay, student . I am working on berkeley java edition . Please can you send me code for Java API . the one i am working on has problems with com.sleepycat.je.
Naveed Ali

August 26, 2018 Reply

how insert data in database? when i insert data in db ntegerBinding.intToEntry( (1, key); , StringBinding.stringToEntry(“GOKHAN ATIL”, data); testDB.put(ke,data); i faced an error .

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