Spring JDBC connection pool best practices

Question

I have a basic Spring JDBC application with a pretty basic configuration:

Answer 1

Definately you can use C3P0, this is developed for enterprise solution. To Check advantages you can follow this answer.

Here is the example code of integration:

@Bean
    public JpaTransactionManager transactionManager() {
        JpaTransactionManager transactionManager =
                new JpaTransactionManager();
        transactionManager.setEntityManagerFactory(entityManagerFactory().getObject());
        return transactionManager;
    }

This Bean is for getting JpaTransactionManager.

@Primary
@Bean
public LocalContainerEntityManagerFactoryBean entityManagerFactory() {

    LocalContainerEntityManagerFactoryBean entityManagerFactoryBean = new LocalContainerEntityManagerFactoryBean();
    entityManagerFactoryBean.setDataSource(dataSource());
    entityManagerFactoryBean.setPersistenceProviderClass(HibernatePersistenceProvider.class);
    entityManagerFactoryBean.setPackagesToScan("YOUR.DATABSE.ENTITY.PACKAGE");
    entityManagerFactoryBean.setJpaProperties(hibProperties());

    return entityManagerFactoryBean;
}

This Bean is for getting LocalContainerEntityManagerFactoryBean. It Takes DataSource ,PersistenceProviderClass , Entity Package Name PackagesToScan and JpaProperties from hibProperties().

@Bean
    public PersistenceExceptionTranslationPostProcessor exceptionTranslation() {
        return new PersistenceExceptionTranslationPostProcessor();
    }

private Properties hibProperties() {
        Properties properties = new Properties();
        properties.put("hibernate.dialect", env.getProperty("hibernate.dialect"));
        properties.put("hibernate.show_sql", env.getProperty("hibernate.show_sql"));
        properties.put("hibernate.hbm2ddl.auto", env.getProperty("hibernate.hbm2ddl.auto"));
        return properties;
    }

Here, env value are comming from application.properties.

Check bellow properties:

hibernate.dialect: org.hibernate.dialect.Oracle12cDialect
hibernate.show_sql: false
hibernate.hbm2ddl.auto: none

The main part is DataSource Setup. That is given bellow:

@Bean
    public ComboPooledDataSource dataSource(){
        ComboPooledDataSource dataSource = new ComboPooledDataSource();

        try {
            dataSource.setDriverClass(env.getProperty("db.driver"));
            dataSource.setJdbcUrl(env.getProperty("db.url"));
            dataSource.setUser(env.getProperty("db.username"));
            dataSource.setPassword(env.getProperty("db.password"));
            dataSource.setMinPoolSize(Integer.parseInt(env.getProperty("minPoolSize")));
            dataSource.setMaxPoolSize(Integer.parseInt(env.getProperty("maxPoolSize")));
            dataSource.setMaxIdleTime(Integer.parseInt(env.getProperty("maxIdleTime")));
            dataSource.setMaxStatements(Integer.parseInt(env.getProperty("maxStatements")));
            dataSource.setMaxStatementsPerConnection(Integer.parseInt(env.getProperty("maxStatementsPerConnection")));
            dataSource.setMaxIdleTimeExcessConnections(10000);

        } catch (PropertyVetoException e) {
            e.printStackTrace();
        }
        return dataSource;
    }

It is using ComboPooledDataSource that is taking many more important parameter's like maxPoolSize,MinPoolSize, MaxIdleSize etc. It's environment parameter are given bellow:

db.driver: oracle.jdbc.driver.OracleDriver // for Oracle
db.username: YOUR_USER_NAME
db.password: YOUR_USER_PASSWORD
db.url: DATABASE_URL
minPoolSize:5 // number of minimum poolSize
maxPoolSize:100 // number of maximum poolSize
maxIdleTime:5 // In seconds. After that time it will realease the unused connection.
maxStatements:1000
maxStatementsPerConnection:100
maxIdleTimeExcessConnections:10000

Here is the full working sample code:

import com.mchange.v2.c3p0.ComboPooledDataSource;
import org.hibernate.jpa.HibernatePersistenceProvider;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.context.annotation.*;
import org.springframework.core.env.Environment;
import org.springframework.dao.annotation.PersistenceExceptionTranslationPostProcessor;
import org.springframework.data.jpa.repository.config.EnableJpaRepositories;
import org.springframework.orm.jpa.JpaTransactionManager;
import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean;
import org.springframework.transaction.annotation.EnableTransactionManagement;

import javax.sql.DataSource;
import java.beans.PropertyVetoException;
import java.util.Properties;

@Configuration
@EnableTransactionManagement
@EnableJpaRepositories
@PropertySource("classpath:application.properties")
@Scope("singleton")
public class TestDataSource {

    @Autowired
    private Environment env;

    @Qualifier("dataSource")
    @Autowired
    private DataSource dataSource;

    @Bean
    public JpaTransactionManager transactionManager() {
        JpaTransactionManager transactionManager =
                new JpaTransactionManager();
        transactionManager.setEntityManagerFactory(entityManagerFactory().getObject());
        return transactionManager;
    }

    @Primary
    @Bean
    public LocalContainerEntityManagerFactoryBean entityManagerFactory() {

        LocalContainerEntityManagerFactoryBean entityManagerFactoryBean = new LocalContainerEntityManagerFactoryBean();
        entityManagerFactoryBean.setDataSource(dataSource());
        entityManagerFactoryBean.setPersistenceProviderClass(HibernatePersistenceProvider.class);
        entityManagerFactoryBean.setPackagesToScan("YOUR.PACKAGE.NAME");
        entityManagerFactoryBean.setJpaProperties(hibProperties());

        return entityManagerFactoryBean;
    }

    @Bean
    public PersistenceExceptionTranslationPostProcessor exceptionTranslation() {
        return new PersistenceExceptionTranslationPostProcessor();
    }

    @Bean
    public ComboPooledDataSource dataSource(){
        ComboPooledDataSource dataSource = new ComboPooledDataSource();

        try {
            dataSource.setDriverClass(env.getProperty("db.driver"));
            dataSource.setJdbcUrl(env.getProperty("db.url"));
            dataSource.setUser(env.getProperty("db.username"));
            dataSource.setPassword(env.getProperty("db.password"));
            dataSource.setMinPoolSize(Integer.parseInt(env.getProperty("minPoolSize")));
            dataSource.setMaxPoolSize(Integer.parseInt(env.getProperty("maxPoolSize")));
            dataSource.setMaxIdleTime(Integer.parseInt(env.getProperty("maxIdleTime")));
            dataSource.setMaxStatements(Integer.parseInt(env.getProperty("maxStatements")));
            dataSource.setMaxStatementsPerConnection(Integer.parseInt(env.getProperty("maxStatementsPerConnection")));
            dataSource.setMaxIdleTimeExcessConnections(10000);

        } catch (PropertyVetoException e) {
            e.printStackTrace();
        }
        return dataSource;
    }

    private Properties hibProperties() {
        Properties properties = new Properties();
        properties.put("hibernate.dialect", env.getProperty("hibernate.dialect"));
        properties.put("hibernate.show_sql", env.getProperty("hibernate.show_sql"));
        properties.put("hibernate.hbm2ddl.auto", env.getProperty("hibernate.hbm2ddl.auto"));
        return properties;
    }
}

Another things. Here is the gradle link

compile group: 'org.hibernate', name: 'hibernate-c3p0', version: '5.2.10.Final'

Hope this will help you. Thanks :)