在Spring 3.1之前，注册一个配置文件的唯一方法就是

bash
<context:property-placeholder location="some.properties"/>

Spring 3.1引入了PropertySource和Environment接口，可以通过@PropertySource注解来注册

bash
@Configuration
@PropertySource("classpath:some.properties")
public class ApplicationConfiguration

并且从Spring 3.1之后，<context:property-placeholder>实际底层注册的是PropertySourcesPlaceholderConfigurer对象。 这个对象具有更好的扩展性并且和Environment，PropertySource接口交互。

使用PropertySourceH2

推荐的使用方式是

bash
@Configuration
@PropertySource("classpath:some.properties")
public class ApplicationConfiguration

然后注入environment

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@Inject
private Environment environment;

通过Environment实例来读取配置

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environment.getProperty("foo.bar")

在Spring 3.2中使用@Value注解H3

使用@PropertySource注解并没有注册PropertySourcesPlaceholderConfigurer(或者PropertyPlaceholderConfigurer)对象。@Value和Environment的机制是独立的，并且environment是推荐的方式。

如果仍想使用@Value注解，可以注册PropertySourcesPlaceholderConfigurer对象来让其调用Environment接口达到目的。

Mocking PropertySourceH2

Mock一个PropertySource，添加如下代码到测试代码中

bash
public static class PropertyMockingApplicationContextInitializer implements ApplicationContextInitializer<ConfigurableApplicationContext> {

    @Override
    public void initialize(ConfigurableApplicationContext applicationContext) {
        MutablePropertySources propertySources = applicationContext.getEnvironment().getPropertySources();
        MockPropertySource mockEnvVars = new MockPropertySource().withProperty("bundling.enabled", false);
        propertySources.replace(StandardEnvironment.SYSTEM_ENVIRONMENT_PROPERTY_SOURCE_NAME, mockEnvVars);
    }
}

bash
@ContextConfiguration(classes = ApplicationConfiguration.class, initializers = MyIntegrationTest.TestApplicationContextInitializer.class)

或者直接添加Environment的mock对象

bash
public static class PropertyMockingApplicationContextInitializer implements ApplicationContextInitializer<ConfigurableApplicationContext> {

    @Override
    public void initialize(ConfigurableApplicationContext applicationContext) {
        MockEnvironment mockEnvironment = new MockEnvironment();
        applicationContext.setEnvironment(mockEnvironment);
    }
}