Initial Commit (#4427)

hibernate5/src/main/java/com/baeldung/hibernate/jpabootstrap/application/Application.java

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+package com.baeldung.hibernate.jpabootstrap.application;
+
+import com.baeldung.hibernate.jpabootstrap.config.JpaEntityManagerFactory;
+import com.baeldung.hibernate.jpabootstrap.entities.User;
+import javax.persistence.EntityManager;
+
+public class Application {
+    
+    public static void main(String[] args) {
+        EntityManager entityManager = getJpaEntityManager();
+        User user = entityManager.find(User.class, 1);
+        System.out.println(user);
+        entityManager.getTransaction().begin();
+        user.setName("John");
+        user.setEmail("john@domain.com");
+        entityManager.merge(user);
+        entityManager.getTransaction().commit();
+        entityManager.getTransaction().begin();
+        entityManager.persist(new User("Monica", "monica@domain.com"));
+        entityManager.getTransaction().commit();
+ 
+         // additional CRUD operations
+         
+    }
+
+    private static class EntityManagerHolder {
+        private static final EntityManager ENTITY_MANAGER = new JpaEntityManagerFactory(
+          new Class[]{User.class}).getEntityManager();
+    }
+    
+    public static EntityManager getJpaEntityManager() {
+        return EntityManagerHolder.ENTITY_MANAGER;
+    }
+}

hibernate5/src/main/java/com/baeldung/hibernate/jpabootstrap/config/HibernatePersistenceUnitInfo.java

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+package com.baeldung.hibernate.jpabootstrap.config;
+
+import java.net.URL;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.Properties;
+import javax.sql.DataSource;
+import javax.persistence.SharedCacheMode;
+import javax.persistence.ValidationMode;
+import javax.persistence.spi.ClassTransformer;
+import javax.persistence.spi.PersistenceUnitInfo;
+import javax.persistence.spi.PersistenceUnitTransactionType;
+import org.hibernate.jpa.HibernatePersistenceProvider;
+
+public class HibernatePersistenceUnitInfo implements PersistenceUnitInfo {
+    
+    public static final String JPA_VERSION = "2.1";
+    private final String persistenceUnitName;
+    private PersistenceUnitTransactionType transactionType = PersistenceUnitTransactionType.RESOURCE_LOCAL;
+    private final List<String> managedClassNames;
+    private final List<String> mappingFileNames = new ArrayList<>();
+    private final Properties properties;
+    private DataSource jtaDataSource;
+    private DataSource nonjtaDataSource;
+    private final List<ClassTransformer> transformers = new ArrayList<>();
+    
+    public HibernatePersistenceUnitInfo(String persistenceUnitName, List<String> managedClassNames, Properties properties) {
+        this.persistenceUnitName = persistenceUnitName;
+        this.managedClassNames = managedClassNames;
+        this.properties = properties;
+    }
+    
+    @Override
+    public String getPersistenceUnitName() {
+        return persistenceUnitName;
+    }
+ 
+    @Override
+    public String getPersistenceProviderClassName() {
+        return HibernatePersistenceProvider.class.getName();
+    }
+ 
+    @Override
+    public PersistenceUnitTransactionType getTransactionType() {
+        return transactionType;
+    }
+ 
+    public HibernatePersistenceUnitInfo  setJtaDataSource(DataSource jtaDataSource) {
+        this.jtaDataSource = jtaDataSource;
+        this.nonjtaDataSource = null;
+        transactionType = PersistenceUnitTransactionType.JTA;
+        return this;
+    }
+ 
+    @Override
+    public DataSource getJtaDataSource() {
+        return jtaDataSource;
+    }
+    
+    public HibernatePersistenceUnitInfo setNonJtaDataSource(DataSource nonJtaDataSource) {
+        this.nonjtaDataSource = nonJtaDataSource;
+        this.jtaDataSource = null;
+        transactionType = PersistenceUnitTransactionType.RESOURCE_LOCAL;
+        return this;
+    }
+     
+    @Override
+    public DataSource getNonJtaDataSource() {
+        return nonjtaDataSource;
+    }
+ 
+    @Override
+    public List<String> getMappingFileNames() {
+        return mappingFileNames;
+    }
+ 
+    @Override
+    public List<URL> getJarFileUrls() {
+        return Collections.emptyList();
+    }
+ 
+    @Override
+    public URL getPersistenceUnitRootUrl() {
+        return null;
+    }
+ 
+    @Override
+    public List<String> getManagedClassNames() {
+        return managedClassNames;
+    }
+ 
+    @Override
+    public boolean excludeUnlistedClasses() {
+        return false;
+    }
+ 
+    @Override
+    public SharedCacheMode getSharedCacheMode() {
+        return SharedCacheMode.UNSPECIFIED;
+    }
+ 
+    @Override
+    public ValidationMode getValidationMode() {
+        return ValidationMode.AUTO;
+    }
+ 
+    public Properties getProperties() {
+        return properties;
+    }
+ 
+    @Override
+    public String getPersistenceXMLSchemaVersion() {
+        return JPA_VERSION;
+    }
+ 
+    @Override
+    public ClassLoader getClassLoader() {
+        return Thread.currentThread().getContextClassLoader();
+    }
+ 
+    @Override
+    public void addTransformer(ClassTransformer transformer) {
+        transformers.add(transformer);
+    }
+    
+    @Override
+    public ClassLoader getNewTempClassLoader() {
+        return null;
+    }
+}

hibernate5/src/main/java/com/baeldung/hibernate/jpabootstrap/config/JpaEntityManagerFactory.java

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+package com.baeldung.hibernate.jpabootstrap.config;
+
+import com.mysql.cj.jdbc.MysqlDataSource;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Properties;
+import java.util.stream.Collectors;
+import javax.persistence.EntityManager;
+import javax.sql.DataSource;
+import javax.persistence.EntityManagerFactory;
+import javax.persistence.spi.PersistenceUnitInfo;
+import org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl;
+import org.hibernate.jpa.boot.internal.PersistenceUnitInfoDescriptor;
+
+public class JpaEntityManagerFactory {
+    
+    private final String DB_URL = "jdbc:mysql://databaseurl";
+    private final String DB_USER_NAME = "username";
+    private final String DB_PASSWORD = "password";
+    private final Class[] entityClasses;
+    
+    public JpaEntityManagerFactory(Class[] entityClasses) {
+        this.entityClasses = entityClasses;
+    }
+            
+    public EntityManager getEntityManager() {
+        return getEntityManagerFactory().createEntityManager();
+    }
+    
+    protected EntityManagerFactory getEntityManagerFactory() {
+        PersistenceUnitInfo persistenceUnitInfo = getPersistenceUnitInfo(getClass().getSimpleName());
+        Map<String, Object> configuration = new HashMap<>();
+        return new EntityManagerFactoryBuilderImpl(new PersistenceUnitInfoDescriptor(persistenceUnitInfo), configuration)
+          .build();
+    }
+    
+    protected HibernatePersistenceUnitInfo getPersistenceUnitInfo(String name) {
+        return new HibernatePersistenceUnitInfo(name, getEntityClassNames(), getProperties());
+    }
+    
+    protected List<String> getEntityClassNames() {
+        return Arrays.asList(getEntities())
+          .stream()
+          .map(Class::getName)
+          .collect(Collectors.toList());
+    }
+    
+    protected Properties getProperties() {
+        Properties properties = new Properties();
+        properties.put("hibernate.dialect", "org.hibernate.dialect.MySQLDialect");
+        properties.put("hibernate.id.new_generator_mappings", false);
+        properties.put("hibernate.connection.datasource", getMysqlDataSource());
+        return properties;
+    }
+    
+    protected Class[] getEntities() {
+        return entityClasses;
+    }
+    
+    protected DataSource getMysqlDataSource() {
+	MysqlDataSource mysqlDataSource = new MysqlDataSource();
+        mysqlDataSource.setURL(DB_URL);
+	mysqlDataSource.setUser(DB_USER_NAME);
+        mysqlDataSource.setPassword(DB_PASSWORD);
+	return mysqlDataSource;
+    }
+}

hibernate5/src/main/java/com/baeldung/hibernate/jpabootstrap/entities/User.java

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+package com.baeldung.hibernate.jpabootstrap.entities;
+
+import javax.persistence.Entity;
+import javax.persistence.GeneratedValue;
+import javax.persistence.GenerationType;
+import javax.persistence.Id;
+import javax.persistence.Table;
+
+@Entity
+@Table(name = "users")
+public class User {
+    
+    @Id
+    @GeneratedValue(strategy = GenerationType.AUTO)
+    private long id;
+    private String name;
+    private String email;
+    
+    public User(){}
+    
+    public User(String name, String email) {
+        this.name = name;
+        this.email = email;
+    }
+    
+    public void setName(String name) {
+        this.name = name;
+    }
+    
+    public void setEmail(String email) {
+        this.email = email;
+    }
+    
+    public long getId() {
+        return id;
+    }
+    
+    public String getName() {
+        return name;
+    }
+
+    public String getEmail() {
+        return email;
+    }
+}