Question

我正在使用swing和JPA创建项目，它工作正常，但现在我想更改此项目以使用JPA而不使用persistence.xml文件。我正在寻找一些例子，但仍未找到任何解决方案。我知道春天已经走了，但我不知道。

有某种方法可以做到这一点，怎么办？

Answer 1

我解决了这个问题。 JPA始终需要persistence.xml，但我可以创建一个简单的persistence.xml设置只有一个persistence-unit，之后我可以创建一个类来定义连接值和其他值。

这里是persistence.xml

<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.0" xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd">
  <persistence-unit name="default">    
    <exclude-unlisted-classes>false</exclude-unlisted-classes>    
  </persistence-unit>
</persistence>

，这里是我设置值的类

import java.util.HashMap;
import java.util.Map;
import javax.persistence.EntityManagerFactory;
import javax.persistence.spi.PersistenceUnitTransactionType;
import org.eclipse.persistence.jpa.PersistenceProvider;
import org.eclipse.persistence.config.PersistenceUnitProperties;

/**
 *
 * @author fernando
 */
public class JPAUtils {  
    private static EntityManagerFactory emf;
    private static final String PERSISTENCE_UNIT = "default"; 
    private static final String DB_NAME = "iguanaauto_db";
    public static String IP_SERVER = "127.000.000.001";

    /** return an entitymanagerfactory */
    public static EntityManagerFactory getEntityManagerFactory(){        
        if(emf == null){
            PersistenceProvider pp = new PersistenceProvider();
            Map<String, String> properties = new HashMap<String, String>();            
            properties.put(PersistenceUnitProperties.TRANSACTION_TYPE, PersistenceUnitTransactionType.RESOURCE_LOCAL.name());                      
            properties.put(PersistenceUnitProperties.JDBC_DRIVER, "com.mysql.jdbc.Driver");
            properties.put(PersistenceUnitProperties.JDBC_URL, "jdbc:mysql://" + IP_SERVER + ":3306/" + DB_NAME + "?createDatabaseIfNotExist=true");
            properties.put(PersistenceUnitProperties.JDBC_USER, "root");
            properties.put(PersistenceUnitProperties.JDBC_PASSWORD, "");
            properties.put(PersistenceUnitProperties.DDL_GENERATION, PersistenceUnitProperties.CREATE_OR_EXTEND);
            properties.put(PersistenceUnitProperties.DDL_GENERATION_MODE, PersistenceUnitProperties.DDL_DATABASE_GENERATION);
            properties.put(PersistenceUnitProperties.LOGGING_LEVEL, "FINE");            
            emf = pp.createEntityManagerFactory(PERSISTENCE_UNIT, properties);
        }
        return emf;
    }

}

没有persistence.xml的Swing项目JPA？

1 个答案: