在persistence.xml文件中读取环境变量 [英] Read Environment Variables in persistence.xml file
问题描述
我想读取persistence.xml文件中的环境变量。
想法是我不希望我的数据库详细信息是从属性文件中读取,因为获取属性文件覆盖更改。我想从环境变量中读取详细信息。
Idea is that i don't want my database details to be read from properties file as there is a change of getting properties file override.Instead i want to read details from environment variables.
有没有办法达到此标准。
Is there any way to achieve this criteria.
Iam使用Spring 3我的独立应用程序将部署在unix机器中。
Iam using Spring 3 my standalone application will be deployed in unix machine.
推荐答案
您可以通过提供Map来更新持久性单元中的属性(请参阅这个)。
You can update properties in a persistence unit by supplying a Map (see this).
方便的是,环境变量可以作为Map检索(参见这个)。
Conveniently, environment variables can be retrieved as a Map (see this).
把两个在一起,您可以动态更新属性带有环境变量的持久性单元。
Put the two together and you can dynamically update properties in your persistence unit with environment variables.
编辑:简单示例...
persistence.xml ...
persistence.xml...
<persistence-unit name="default" transaction-type="RESOURCE_LOCAL">
<provider>
oracle.toplink.essentials.PersistenceProvider
</provider>
<exclude-unlisted-classes>false</exclude-unlisted-classes>
<properties>
<property name="toplink.logging.level" value="INFO"/>
<property name="toplink.jdbc.driver" value="oracle.jdbc.OracleDriver"/>
<property name="toplink.jdbc.url" value="jdbc:oracle:thin:@myhost:l521:MYSID"/>
<property name="toplink.jdbc.password" value="tiger"/>
<property name="toplink.jdbc.user" value="scott"/>
</properties>
</persistence-unit>
使用环境变量更新persistence.xmldefault单元的代码...
code that updates persistence.xml "default" unit with environment variables...
Map<String, String> env = System.getenv();
Map<String, Object> configOverrides = new HashMap<String, Object>();
for (String envName : env.keySet()) {
if (envName.contains("DB_USER")) {
configOverrides.put("toplink.jdbc.user", env.get(envName)));
}
// You can put more code in here to populate configOverrides...
}
EntityManagerFactory emf =
Persistence.createEntityManagerFactory("default", configOverrides);
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