Java JPA - EclipseLink - 如何更改默认架构
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JPA - EclipseLink - How to change default schema
提问by mrzmont
I'm programming a web application using weblogic and oracle. the datasource is configured through JNDI, with a restricted database user who can DML into tables, but can't DDL. As you may guess, that user isn't the owner of those tables, but he's granted access.
我正在使用 weblogic 和 oracle 编写一个 web 应用程序。数据源是通过 JNDI 配置的，具有可以 DML 到表中，但不能 DDL 的受限数据库用户。您可能会猜到，该用户不是这些表的所有者，但他被授予访问权限。
Let's say he is GUEST_USER
假设他是 GUEST_USER
The application is using JPA + EclipseLink, and have lots of entities already defined. I don't want to write in each an every entity class the attribute to change schema. I've tried a SessionCustomizer, with this code.
该应用程序使用 JPA + EclipseLink，并且已经定义了许多实体。我不想在每个实体类中写入更改架构的属性。我已经尝试过使用此代码的 SessionCustomizer。
public class MyCustomizer implements SessionCustomizer{
@Override
public void customize(Session session) throws Exception {
session.executeNonSelectingSQL("ALTER SESSION SET CURRENT_SCHEMA = OWNERS_SCHEMA");
}
}
It seems that there's something uninitiallized, I'm getting a null pointer exception, I'm not even sure if this is the way to change the schema for the connections before they are used. Any samples or ideas?
似乎有一些未初始化的东西，我收到了一个空指针异常，我什至不确定这是否是在使用连接之前更改连接架构的方法。任何样本或想法？
Thanks in advance for your help!
在此先感谢您的帮助！
采纳答案by Mike
If all of the entities use the same schema you can use an xml mapping file to define a default schema.
如果所有实体都使用相同的架构，您可以使用 xml 映射文件来定义默认架构。
Something like this should work (example is for JPA 2.0, change the schemaLocation for 1.0)
这样的事情应该可以工作（示例适用于 JPA 2.0，将 schemaLocation 更改为 1.0）
orm.xml:
orm.xml:
<entity-mappings xmlns="http://java.sun.com/xml/ns/persistence/orm"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/persistence/orm orm_2_0.xsd"
version="2.0">
<persistence-unit-metadata>
<persistence-unit-defaults>
<schema>OWNERS_SCHEMA</schema>
</persistence-unit-defaults>
</persistence-unit-metadata>
. . .
</entity-mappings>
persistence.xml:
持久性.xml：
<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="foo">
. . .
<mapping-file>orm.xml</mapping-file>
. . .
</persistence-unit>
</persistence>
回答by Ati
You can do it programatically. You can configure the default schema value for each session.
您可以以编程方式进行。您可以为每个会话配置默认架构值。
public class MySessionCustomizer implements SessionCustomizer {
private static String schemaName;
public static void setSchemaName(String schemaName) {
MySessionCustomizer.schemaName = schemaName;
}
@Override
public void customize(Session session) throws Exception {
if (StringUtils.hasText(this.schemaName)) {
session.getLogin().setTableQualifier(this.schemaName);
}
}
}
Then set the session customizer to entity manager factory properties:
然后将会话定制器设置为实体管理器工厂属性：
PersistenceUnitProperties.SESSION_CUSTOMIZER
e.g.
例如
propertiesMap.put(PersistenceUnitProperties.SESSION_CUSTOMIZER, MySessionCustomizer.class.getName());
回答by Chris
I use EJBright before querying the database, so by using InterceptorsI'm able to set the schema in the EJB context by looking the current authenticated user.
我在查询数据库之前就使用EJB，因此通过使用拦截器，我可以通过查看当前经过身份验证的用户在 EJB 上下文中设置模式。
Then when I build the entity manager I can set the right schema. In this way, by not specifying the schema before the table name, PostgreSQL will look at the search_pathfor determining which schema to query.
然后当我构建实体管理器时，我可以设置正确的模式。这样，通过不在表名之前指定模式，PostgreSQL 将查看以search_path确定要查询的模式。
<!-- language: lang-java -->
public class Interceptor {
Logger logger = Logger.getLogger(Interceptor.class);
/**
*
* @param ctx is always null before being passed to EJB implementation. We always query database
* for populating context data, making user's session accessible to all EJB implementations
* @return
* @throws Exception
*/
@SuppressWarnings({ "unchecked", "unused" })
@AroundInvoke
public Object intercept(InvocationContext ctx) throws Exception {
Authentication auth = SecurityContextHolder.getContext().getAuthentication();
String ejbName = ctx.getMethod().getDeclaringClass().getSimpleName();
String methodName = ctx.getMethod().getName();
Boolean override_schema = false;
String overridden_schema = "";
logger.info("Intercepting " + ejbName + "." + methodName);
if(auth != null) {
UserDetails userDetails = (UserDetails)auth.getPrincipal();
String username = userDetails.getUsername();
Collection<SimpleGrantedAuthority> permList = (Collection<SimpleGrantedAuthority>) auth.getAuthorities();
List<String> permissions = new ArrayList<String>();
for (SimpleGrantedAuthority authority : permList) {
permissions.add(authority.getAuthority());
}
Query query = getMasterEntityManager()
.createNativeQuery(
"SQL for retrieving the schema by the current logged in user");
query.setParameter("username", username);
List<Object[]> result = null; //query.getResultList();
if(result != null) {
logger.info("Interceptor: context set for " + username);
Object[] userObj = result.get(0);
getContext().getContextData().put("username", username);
getContext().getContextData().put("schema_name",(String)userObj[1]);
}
}
return ctx.proceed();
}
}
Then when you build the entity manager, you can set the schema you want.
然后当你构建实体管理器时，你可以设置你想要的模式。
