我有一个场景,需要在 SAP HANA Cloud 平台(目标运行时是 JAVA Web)中部署我的 vaadin 应用程序(可以与多个数据库(2 个持久单元)正常工作,其中运行时为 tomcat 7)。
我之前的数据库连接是通过以下方式使用 eclipselink 与 MYSQL 进行的
private EntityManager getEntityManager(String dbName) {
EntityManagerFactory emf = null;
Map<String, String> properties = new HashMap<String, String>();
if (dbName.toLowerCase().contains("master"))
properties.put(
PersistenceUnitProperties.ECLIPSELINK_PERSISTENCE_XML,
"/META-INF/persistence.xml");
else
properties.put(
PersistenceUnitProperties.ECLIPSELINK_PERSISTENCE_XML,
"/META-INF/persistenceYear.xml");// +dbName.substring(dbName.length()-4)+".xml");
properties.put("javax.persistence.jdbc.driver", getDriver());
properties
.put("javax.persistence.jdbc.url",
getUrl()
+ dbName
+ "?zeroDateTimeBehavior=convertToNull&useUnicode=yes&characterEncoding=utf-8;charset=utf8;characterSetResults=utf8");// &characterSetResults=utf8");
// properties.put("javax.persistence.jdbc.url",
// getUrl()+dbName+"?useUnicode=yes&characterEncoding=UTF-8;characterSetResults=utf8");
properties.put("javax.persistence.jdbc.user", getUserName());
properties.put("javax.persistence.jdbc.password", getPassword());
properties.put(PersistenceUnitProperties.TABLE_CREATION_SUFFIX,
"engine=InnoDB DEFAULT CHARSET=utf8");
properties.put(PersistenceUnitProperties.DDL_GENERATION,
PersistenceUnitProperties.CREATE_OR_EXTEND);
properties.put(PersistenceUnitProperties.DDL_GENERATION_MODE,
PersistenceUnitProperties.DDL_DATABASE_GENERATION);
// properties.put(PersistenceUnitProperties.CREATE_JDBC_DDL_FILE,"create.sql");
// properties.put(PersistenceUnitProperties.APP_LOCATION,
// ServerFolderPathConstants.PROPERTYFILES);
// Configure Session Customizer which will pipe sql file to db before
// DDL Generation runs
// properties.put(PersistenceUnitProperties.SESSION_CUSTOMIZER,
// "in.calico.finbook.config.common.ImportSQL");
// properties.put("import.sql.file",ServerFolderPathConstants.PROPERTYFILES+"create.sql");
try {
/*
* emf = Persistence.createEntityManagerFactory("finbook",
* properties);
*/
emf = Persistence.createEntityManagerFactory(getUnit(), properties);
} catch (Exception e) {
// System.out.println(e.getMessage());
e.printStackTrace();
}
return emf.createEntityManager();
}
上述方法有助于连接到数据库(MYSQL)并返回实体管理器。
我的应用程序需要相同的方法,该应用程序将部署在 SAP HANA CLOUD 中。我想知道如何获取实体管理器(多个数据库)以及如何创建我需要连接的模式?
请帮助我。
最佳答案
在阅读了 sap hana 云平台的完整文档后,我弄清楚了,我在 sap hana 驾驶舱的 java 应用程序部分部署了我的 war 文件。通过 JPA 2.0,我连接到 SAP DB ( source to create DB and binding is ) 并获取下面代码的实体管理器对象有很大帮助
import javax.sql.DataSource;
import javax.annotation.Resource;
import javax.annotation.Resources;
import javax.naming.InitialContext;
import javax.naming.NamingException;
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;
import javax.servlet.annotation.WebServlet;
{
DataSource ds =null;
EntityManagerFactory emf;
InitialContext ctx = null;
try {
ctx = new InitialContext();
} catch (NamingException e) {
e.printStackTrace();
}
try {
//Note: jdbc/fbk is data source name which we'll give at binding database, by default it will be as "<default>" edit that to jdbc/fbk or else anything
ds = (DataSource) ctx.lookup("java:comp/env/jdbc/fbk");
} catch (NamingException e) {
e.printStackTrace();
}
@SuppressWarnings("rawtypes")
Map properties = new HashMap();
properties.put(PersistenceUnitProperties.JTA_DATASOURCE, ds);
properties.put(PersistenceUnitProperties.DDL_GENERATION,
PersistenceUnitProperties.CREATE_OR_EXTEND);
properties.put(PersistenceUnitProperties.DDL_GENERATION_MODE,
PersistenceUnitProperties.DDL_DATABASE_GENERATION);
emf = Persistence.createEntityManagerFactory("pu", properties);
EntityManager em = emf.createEntityManager();
return em;
}
persistence.xml代码是:
<?xml version="1.0" encoding="UTF-8"?>
<persistence 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"
version="2.0">
<persistence-unit name="pu" transaction-type="JTA">
<provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
<class>Vaadin_Sample.hell.FunctionKey</class>
<properties>
</properties>
</persistence-unit>
</persistence>
资源映射是在以下注释的帮助下完成的:
@WebServlet(urlPatterns = "/*", name = "MyUIServlet", asyncSupported = true)
@VaadinServletConfiguration(ui = MyUI.class, productionMode = false)
@Resource(name="jdbc/fbk",type=DataSource.class)
public static class MyUIServlet extends VaadinServlet {
}
注意:以上所有过程仅由COCKPIT试用帐户完成。
关于java - SAP HANA Cloud如何支持多个数据库?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/31935513/