Initial commit

src/main/java/jpa/EntityManagerHelper.java

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+package jpa;
+
+import jakarta.persistence.EntityManager;
+import jakarta.persistence.EntityManagerFactory;
+import jakarta.persistence.Persistence;
+
+public class EntityManagerHelper {
+
+    private static final EntityManagerFactory emf; 
+    private static final ThreadLocal<EntityManager> threadLocal;
+
+    static {
+        emf = Persistence.createEntityManagerFactory("dev");      
+        threadLocal = new ThreadLocal<EntityManager>();
+    }
+
+    public static EntityManager getEntityManager() {
+        EntityManager em = threadLocal.get();
+
+        if (em == null) {
+            em = emf.createEntityManager();
+            threadLocal.set(em);
+        }
+        return em;
+    }
+
+    public static void closeEntityManager() {
+        EntityManager em = threadLocal.get();
+        if (em != null) {
+            em.close();
+            threadLocal.set(null);
+        }
+    }
+
+    public static void closeEntityManagerFactory() {
+        emf.close();
+    }
+
+    public static void beginTransaction() {
+        getEntityManager().getTransaction().begin();
+    }
+
+    public static void rollback() {
+        getEntityManager().getTransaction().rollback();
+    }
+
+    public static void commit() {
+        getEntityManager().getTransaction().commit();
+    } 
+}

src/main/java/jpa/JpaTest.java

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+package jpa;
+
+
+import jakarta.persistence.EntityManager;
+import jakarta.persistence.EntityTransaction;
+
+public class JpaTest {
+
+
+	private EntityManager manager;
+
+	public JpaTest(EntityManager manager) {
+		this.manager = manager;
+	}
+	/**
+	 * @param args
+	 */
+	public static void main(String[] args) {
+			EntityManager manager = EntityManagerHelper.getEntityManager();
+
+		JpaTest test = new JpaTest(manager);
+
+		EntityTransaction tx = manager.getTransaction();
+		tx.begin();
+		try {
+
+			// TODO create and persist entity
+		} catch (Exception e) {
+			e.printStackTrace();
+		}
+		tx.commit();
+
+			
+   	 manager.close();
+		EntityManagerHelper.closeEntityManagerFactory();
+		System.out.println(".. done");
+	}
+
+
+
+
+}

src/main/resources/META-INF/persistence.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<persistence xmlns="https://jakarta.ee/xml/ns/persistence"
+	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="https://jakarta.ee/xml/ns/persistence https://jakarta.ee/xml/ns/persistence/persistence_3_0.xsd"
+	version="3.0">
+
+	<persistence-unit name="dev" transaction-type="RESOURCE_LOCAL">
+		<provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>
+		<properties>
+			<property name="jakarta.persistence.jdbc.driver"
+				value="org.hsqldb.jdbcDriver" />
+			<property name="jakarta.persistence.jdbc.url"
+				value="jdbc:hsqldb:hsql://localhost/" />
+			<property name="jakarta.persistence.jdbc.user" value="sa" />
+			<property name="jakarta.persistence.jdbc.password" value="" />
+			<property
+				name="jakarta.persistence.schema-generation.database.action"
+				value="create" />
+			<property name="jakarta.persistence.dialect"
+				value="org.hibernate.dialect.HSQLDialect" />
+			<property name="hibernate.show_sql" value="true" />
+		</properties>
+	</persistence-unit>
+	<persistence-unit name="prod" transaction-type="RESOURCE_LOCAL">
+		<provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>
+		<properties>
+			<property name="jakarta.persistence.jdbc.driver"
+				value="org.hsqldb.jdbcDriver" />
+			<property name="jakarta.persistence.jdbc.url"
+				value="jdbc:hsqldb:hsql://localhost/" />
+			<property name="jakarta.persistence.jdbc.user" value="sa" />
+			<property name="jakarta.persistence.jdbc.password" value="" />
+			<property
+				name="jakarta.persistence.schema-generation.database.action"
+				value="update" />
+			<property name="jakarta.persistence.dialect"
+				value="org.hibernate.dialect.HSQLDialect" />
+			<property name="hibernate.show_sql" value="true" />
+
+		</properties>
+	</persistence-unit>
+
+	<persistence-unit name="mysql">
+		<provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>
+ 
+		<properties>
+			<property name="jakarta.persistence.jdbc.driver"
+				value="com.mysql.cj.jdbc.Driver" />
+			<property name="jakarta.persistence.jdbc.url"
+				value="jdbc:mysql://localhost/mydatabase" />
+			<property name="jakarta.persistence.jdbc.user" value="tlc" />
+			<property name="jakarta.persistence.jdbc.password" value="tlc" />
+			<property
+				name="jakarta.persistence.schema-generation.database.action"
+				value="update" />
+			<property name="jakarta.persistence.dialect"
+				value="org.hibernate.dialect.MySQL8Dialect" />
+			<property name="hibernate.show_sql" value="true" />
+			<property name="hibernate.c3p0.min_size" value="5" />
+			<property name="hibernate.c3p0.max_size" value="20" />
+			<property name="hibernate.c3p0.timeout" value="300" />
+			<property name="hibernate.c3p0.max_statements" value="50" />
+			<property name="hibernate.c3p0.idle_test_period" value="3000" />
+		</properties>
+	</persistence-unit>
+
+</persistence>

src/main/resources/log4j.properties

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+----------------------------------------------log4j.properties
+
+### direct log messages to stdout
+###
+log4j.rootLogger=INFO, stdout
+log4j.appender.stdout=org.apache.log4j.ConsoleAppender
+log4j.appender.stdout.Target=System.out
+log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
+log4j.appender.stdout.layout.ConversionPattern=%d{ABSOLUTE} %5p %c{1}:%L - %m%n
+
+# Log everything. Good for troubleshooting
+log4j.logger.org.hibernate=ERROR
+
+# Log all JDBC parameters
+log4j.logger.org.hibernate.type=ERROR