How to store properties value in database and convert to re cache in java

Kartik Chandra Mandal March 05, 2019


To store properties values in a database and re-utilize them for future use in Java, you can follow a systematic approach that involves saving the properties in a relational database, loading them when needed, and caching them for quick access. Below is a step-by-step guide on how to achieve this:

1. Define the Properties Table in the Database

First, you need to create a table in the database to store the properties. Each property will have a key and a value, and you can optionally include other metadata.

Example SQL Table Structure

sql

CREATE TABLE properties (

    id INT AUTO_INCREMENT PRIMARY KEY,

    property_key VARCHAR(255) UNIQUE NOT NULL,

    property_value VARCHAR(255) NOT NULL,

    description VARCHAR(255),

    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP

);

 

2. Store Properties in the Database

You can store the properties in the database using JDBC in Java. Here's how to do it:

Example Code to Store Properties in the Database

java

import java.sql.Connection;

import java.sql.DriverManager;

import java.sql.PreparedStatement;

import java.sql.SQLException;

import java.util.Properties;

 

public class PropertiesDatabase {

 

    private static final String DB_URL = "jdbc:mysql://localhost:3306/your_database";

    private static final String USER = "username";

    private static final String PASS = "password";

 

    public void storeProperties(Properties properties) {

        String insertSQL = "INSERT INTO properties (property_key, property_value) VALUES (?, ?) "

                + "ON DUPLICATE KEY UPDATE property_value = VALUES(property_value)";

 

        try (Connection connection = DriverManager.getConnection(DB_URL, USER, PASS);

             PreparedStatement preparedStatement = connection.prepareStatement(insertSQL)) {

 

            for (String key : properties.stringPropertyNames()) {

                preparedStatement.setString(1, key);

                preparedStatement.setString(2, properties.getProperty(key));

                preparedStatement.executeUpdate();

            }

 

        } catch (SQLException e) {

            e.printStackTrace();

        }

    }

}

 

3. Load Properties from the Database

When your application starts or when the properties are needed, you can load them from the database into a Properties object or a cache for quick access.

Example Code to Load Properties from the Database

java

import java.sql.Connection;

import java.sql.DriverManager;

import java.sql.PreparedStatement;

import java.sql.ResultSet;

import java.sql.SQLException;

import java.util.Properties;

 

public class PropertiesDatabase {

 

    private static final String DB_URL = "jdbc:mysql://localhost:3306/your_database";

    private static final String USER = "username";

    private static final String PASS = "password";

 

    public Properties loadProperties() {

        Properties properties = new Properties();

        String querySQL = "SELECT property_key, property_value FROM properties";

 

        try (Connection connection = DriverManager.getConnection(DB_URL, USER, PASS);

             PreparedStatement preparedStatement = connection.prepareStatement(querySQL);

             ResultSet resultSet = preparedStatement.executeQuery()) {

 

            while (resultSet.next()) {

                String key = resultSet.getString("property_key");

                String value = resultSet.getString("property_value");

                properties.setProperty(key, value);

            }

 

        } catch (SQLException e) {

            e.printStackTrace();

        }

        return properties;

    }

}

 

4. Cache or Re-Utilize the Properties

To make the properties easily accessible and re-utilizable throughout your application, you can cache them in memory using a Map, a Properties object, or a more sophisticated caching mechanism like Ehcache or Redis.

Example of a Simple In-Memory Cache

java

import java.util.HashMap;

import java.util.Map;

import java.util.Properties;

 

public class PropertiesCache {

 

    private final Map<String, String> cache = new HashMap<>();

 

    public void loadToCache(Properties properties) {

        for (String key : properties.stringPropertyNames()) {

            cache.put(key, properties.getProperty(key));

        }

    }

 

    public String getProperty(String key) {

        return cache.get(key);

    }

 

    public void updateCache(String key, String value) {

        cache.put(key, value);

    }

 

    public void clearCache() {

        cache.clear();

    }

}

  

Or another Java

import java.util.HashMap;

import java.util.Map;

import java.util.Map.Entry;

import java.util.Properties;

 

/**

 *

 * @author kmandal

 *

 */

public class PropertiesReader {

 

 private static Map<String,String> propertiesCache = new HashMap<String,String>();

 

 /**

  * Injects properties from *.properties(one or more files) from spring framework.

  * @param properties

  */

 public void setProperties(Properties...properties) {

 

  if(properties != null && properties.length > 0) {

   for (Properties property : properties) {

    for (Entry<Object, Object> entry : property.entrySet()) {

     propertiesCache.put((String)entry.getKey(), (String)entry.getValue());

    }

   

   }

  }

 }

 

 /**

  * Gets property value for a given key.

  * @param keyName

  * @return

  */

 public static String getPropertyByKey(final String keyName) {

  return propertiesCache.get(keyName);

 }

 

 /**

  * Replaces {} with value.

  * @param keyName

  * @param replaceBraces

  * @return

  */

 public static String getPropertyByKey(final String keyName, String...replaceBraces) {

 

  String sPropValue = getPropertyByKey(keyName);

   

  if(sPropValue != null && sPropValue.contains("{}")) {

   if (replaceBraces != null && replaceBraces.length > 0) {

    for (String replaceBrace : replaceBraces) {

     sPropValue = sPropValue.replace("{}", replaceBrace);

    }

   }

  }

  

  System.out.println("****Key : "+keyName+", value : "+sPropValue);

 

  return sPropValue;

 

 }

}

 

5. Re-Utilize Properties in the Application

Now that the properties are loaded into memory, you can easily retrieve them whenever needed:

Example Usage

java

public class Main {

 

    public static void main(String[] args) {

        // Step 1: Load properties from the database

        PropertiesDatabase propertiesDatabase = new PropertiesDatabase();

        Properties loadedProperties = propertiesDatabase.loadProperties();

 

        // Step 2: Load properties into cache

        PropertiesCache propertiesCache = new PropertiesCache();

        propertiesCache.loadToCache(loadedProperties);

 

        // Step 3: Access properties from the cache

        String appName = propertiesCache.getProperty("app.name");

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

 

        // Step 4: Update a property

        propertiesCache.updateCache("app.version", "1.1.0");

 

        // Step 5: Clear the cache if needed

        propertiesCache.clearCache();

    }

}

 

6. Update Properties

If you need to update the properties, you can update the database and refresh the cache.

Example Code to Update a Property

java

public void updateProperty(String key, String value) {

    String updateSQL = "UPDATE properties SET property_value = ? WHERE property_key = ?";

 

    try (Connection connection = DriverManager.getConnection(DB_URL, USER, PASS);

         PreparedStatement preparedStatement = connection.prepareStatement(updateSQL)) {

 

        preparedStatement.setString(1, value);

        preparedStatement.setString(2, key);

        preparedStatement.executeUpdate();

 

    } catch (SQLException e) {

        e.printStackTrace();

    }

}

 

7. Automatically Refresh Cache

You can enhance the application by implementing a mechanism to automatically refresh the cache when properties change, such as using a scheduled task or a trigger in the database that notifies the application.

Summary

  • Store Properties: Use JDBC to store properties in a relational database.
  • Load Properties: Load properties from the database into a Properties object.
  • Cache Properties: Store the properties in memory for quick access using a Map or a more advanced caching framework.
  • Re-Utilize Properties: Access the properties from the cache throughout your application.
  • Update Properties: Modify properties in the database and refresh the cache as needed.

This approach ensures that your properties are stored persistently, can be loaded and reused easily, and are accessible across different parts of your application.

 


Approach 2



Storing properties values in a database and converting them back into a cache in Java involves several steps. Below, I'll guide you through the process, assuming you want to use a database like MySQL and a caching solution such as a simple in-memory cache or a more advanced one like Ehcache or Redis.

1. Define the Properties Structure

You need to decide how to structure your properties in the database. Typically, a table can be created with columns for the key and value of each property.

Example SQL Table Structure

sql

CREATE TABLE properties (

    id INT AUTO_INCREMENT PRIMARY KEY,

    property_key VARCHAR(255) UNIQUE NOT NULL,

    property_value VARCHAR(255) NOT NULL

);

 

2. Store Properties in the Database

You can store key-value pairs of your properties in the database using JDBC in Java.

Example Code to Store Properties

java

import java.sql.Connection;

import java.sql.DriverManager;

import java.sql.PreparedStatement;

import java.sql.SQLException;

import java.util.Properties;

 

public class PropertiesDatabase {

 

    private static final String DB_URL = "jdbc:mysql://localhost:3306/your_database";

    private static final String USER = "username";

    private static final String PASS = "password";

 

    public void storeProperties(Properties properties) {

        String insertSQL = "INSERT INTO properties (property_key, property_value) VALUES (?, ?) "

                + "ON DUPLICATE KEY UPDATE property_value = VALUES(property_value)";

 

        try (Connection connection = DriverManager.getConnection(DB_URL, USER, PASS);

             PreparedStatement preparedStatement = connection.prepareStatement(insertSQL)) {

 

            for (String key : properties.stringPropertyNames()) {

                preparedStatement.setString(1, key);

                preparedStatement.setString(2, properties.getProperty(key));

                preparedStatement.executeUpdate();

            }

 

        } catch (SQLException e) {

            e.printStackTrace();

        }

    }

}

 

3. Load Properties from Database

To reload the properties from the database into your application, you'll need to query the database and load the values into a Properties object or directly into your cache.

Example Code to Load Properties

java

import java.sql.Connection;

import java.sql.DriverManager;

import java.sql.PreparedStatement;

import java.sql.ResultSet;

import java.sql.SQLException;

import java.util.Properties;

 

public class PropertiesDatabase {

 

    private static final String DB_URL = "jdbc:mysql://localhost:3306/your_database";

    private static final String USER = "username";

    private static final String PASS = "password";

 

    public Properties loadProperties() {

        Properties properties = new Properties();

        String querySQL = "SELECT property_key, property_value FROM properties";

 

        try (Connection connection = DriverManager.getConnection(DB_URL, USER, PASS);

             PreparedStatement preparedStatement = connection.prepareStatement(querySQL);

             ResultSet resultSet = preparedStatement.executeQuery()) {

 

            while (resultSet.next()) {

                String key = resultSet.getString("property_key");

                String value = resultSet.getString("property_value");

                properties.setProperty(key, value);

            }

 

        } catch (SQLException e) {

            e.printStackTrace();

        }

        return properties;

    }

}

 

4. Cache the Loaded Properties

Once the properties are loaded from the database, you can store them in a cache. If you're using a simple in-memory cache, you can use a Map or a more advanced caching framework like Ehcache or Redis.

Example of Caching with a Simple Map

java

import java.util.HashMap;

import java.util.Map;

import java.util.Properties;

 

public class PropertiesCache {

 

    private final Map<String, String> cache = new HashMap<>();

 

    public void loadToCache(Properties properties) {

        for (String key : properties.stringPropertyNames()) {

            cache.put(key, properties.getProperty(key));

        }

    }

 

    public String getProperty(String key) {

        return cache.get(key);

    }

}

 

 

Or another Java

import java.util.HashMap;

import java.util.Map;

import java.util.Map.Entry;

import java.util.Properties;

 

/**

 *

 * @author kmandal

 *

 */

public class PropertiesReader {

 

 private static Map<String,String> propertiesCache = new HashMap<String,String>();

 

 /**

  * Injects properties from *.properties(one or more files) from spring framework.

  * @param properties

  */

 public void setProperties(Properties...properties) {

 

  if(properties != null && properties.length > 0) {

   for (Properties property : properties) {

    for (Entry<Object, Object> entry : property.entrySet()) {

     propertiesCache.put((String)entry.getKey(), (String)entry.getValue());

    }

   

   }

  }

 }

 

 /**

  * Gets property value for a given key.

  * @param keyName

  * @return

  */

 public static String getPropertyByKey(final String keyName) {

  return propertiesCache.get(keyName);

 }

 

 /**

  * Replaces {} with value.

  * @param keyName

  * @param replaceBraces

  * @return

  */

 public static String getPropertyByKey(final String keyName, String...replaceBraces) {

 

  String sPropValue = getPropertyByKey(keyName);

   

  if(sPropValue != null && sPropValue.contains("{}")) {

   if (replaceBraces != null && replaceBraces.length > 0) {

    for (String replaceBrace : replaceBraces) {

     sPropValue = sPropValue.replace("{}", replaceBrace);

    }

   }

  }

  

  System.out.println("****Key : "+keyName+", value : "+sPropValue);

 

  return sPropValue;

 

 }

}

 

Example of Caching with Ehcache

java

import org.ehcache.Cache;

import org.ehcache.CacheManager;

import org.ehcache.config.builders.CacheConfigurationBuilder;

import org.ehcache.config.builders.CacheManagerBuilder;

import org.ehcache.config.builders.ResourcePoolsBuilder;

 

public class PropertiesEhcache {

 

    private final Cache<String, String> cache;

 

    public PropertiesEhcache() {

        CacheManager cacheManager = CacheManagerBuilder.newCacheManagerBuilder().build();

        cacheManager.init();

 

        cache = cacheManager.createCache("propertiesCache",

                CacheConfigurationBuilder.newCacheConfigurationBuilder(String.class, String.class,

                        ResourcePoolsBuilder.heap(100)));

    }

 

    public void loadToCache(Properties properties) {

        for (String key : properties.stringPropertyNames()) {

            cache.put(key, properties.getProperty(key));

        }

    }

 

    public String getProperty(String key) {

        return cache.get(key);

    }

}

 

5. Usage Example

Here’s how you can use the above classes:

java

public class Main {

 

    public static void main(String[] args) {

        PropertiesDatabase propertiesDatabase = new PropertiesDatabase();

 

        // Example: Store properties

        Properties propertiesToStore = new Properties();

        propertiesToStore.setProperty("app.name", "MyApp");

        propertiesToStore.setProperty("app.version", "1.0.0");

        propertiesDatabase.storeProperties(propertiesToStore);

 

        // Example: Load properties from the database

        Properties loadedProperties = propertiesDatabase.loadProperties();

 

        // Example: Load properties into cache

        PropertiesCache propertiesCache = new PropertiesCache();

        propertiesCache.loadToCache(loadedProperties);

 

        // Example: Access a property from cache

        String appName = propertiesCache.getProperty("app.name");

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

    }

}

 

Summary

  • Store properties: Use a Properties object and JDBC to store properties in a database.
  • Load properties: Load the properties from the database back into a Properties object.
  • Cache properties: Use a simple in-memory Map or a caching framework like Ehcache to cache the properties.
  • Access properties: Retrieve properties from the cache as needed.

This approach allows you to manage application configurations dynamically and ensures that the properties can be reloaded and cached efficiently.

 

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Properties object and JDBC to store properties in a database
Properties object and JDBC to store properties in a database





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