JpaConfig.java

package thymeleafexamples.layouts.config;

import com.zaxxer.hikari.HikariConfig;
import com.zaxxer.hikari.HikariDataSource;
import org.hibernate.cfg.Environment;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.jpa.convert.threeten.Jsr310JpaConverters;
import org.springframework.data.jpa.repository.config.EnableJpaRepositories;
import org.springframework.orm.jpa.JpaTransactionManager;
import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean;
import org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter;
import org.springframework.transaction.PlatformTransactionManager;
import org.springframework.transaction.annotation.EnableTransactionManagement;
import org.springframework.util.ClassUtils;
import thymeleafexamples.layouts.Application;

import javax.persistence.EntityManagerFactory;
import javax.sql.DataSource;
import java.util.Properties;

@Configuration
@EnableTransactionManagement
@EnableJpaRepositories(basePackageClasses = Application.class)
class JpaConfig {

    @Value("${dataSource.driverClassName}")
    private String driver;
    @Value("${dataSource.url}")
    private String url;
    @Value("${dataSource.username}")
    private String username;
    @Value("${dataSource.password}")
    private String password;
    @Value("${hibernate.dialect}")
    private String dialect;
    @Value("${hibernate.hbm2ddl.auto}")
    private String hbm2ddlAuto;
    @Value("${hibernate.show_sql}")
    private String showSql;
    @Value("${hibernate.format_sql}")
    private String formatSql;
    @Value("${hibernate.use_sql_comments}")
    private String useSqlComments;

    @Bean
    public DataSource dataSource() {
        HikariConfig config = new HikariConfig();
        config.setDriverClassName(driver);
        config.setJdbcUrl(url);
        config.setUsername(username);
        config.setPassword(password);
        config.addDataSourceProperty("cachePrepStmts", "true");
        config.addDataSourceProperty("prepStmtCacheSize", "250");
        config.addDataSourceProperty("prepStmtCacheSqlLimit", "2048");
        config.addDataSourceProperty("useServerPrepStmts", "true");

        return new HikariDataSource(config);
    }

    @Bean
    public LocalContainerEntityManagerFactoryBean entityManagerFactory(DataSource dataSource) {
        LocalContainerEntityManagerFactoryBean entityManagerFactoryBean = new LocalContainerEntityManagerFactoryBean();
        entityManagerFactoryBean.setDataSource(dataSource);

        String entities = ClassUtils.getPackageName(Application.class);
        String converters = ClassUtils.getPackageName(Jsr310JpaConverters.class);
        entityManagerFactoryBean.setPackagesToScan(entities, converters);

        entityManagerFactoryBean.setJpaVendorAdapter(new HibernateJpaVendorAdapter());

        Properties jpaProperties = new Properties();
        jpaProperties.put(Environment.DIALECT, dialect);
        jpaProperties.put(Environment.HBM2DDL_AUTO, hbm2ddlAuto);
        jpaProperties.put(Environment.SHOW_SQL, showSql);
        jpaProperties.put(Environment.FORMAT_SQL, formatSql);
        jpaProperties.put(Environment.USE_SQL_COMMENTS, useSqlComments);
        entityManagerFactoryBean.setJpaProperties(jpaProperties);

        return entityManagerFactoryBean;
    }

    @Bean
    public PlatformTransactionManager transactionManager(EntityManagerFactory entityManagerFactory) {
        return new JpaTransactionManager(entityManagerFactory);
    }
}