Question

我正在创建一个新项目并尝试使用Java配置，我之前使用的是XML配置。我的应用需要<property-placeholder>之类的配置。我有一个如下配置：

@Configuration
@PropertySources({
    @PropertySource(ignoreResourceNotFound = true,
                    value = "classpath:app.config.properties"),
    @PropertySource(ignoreResourceNotFound = true,
                    value = "classpath:app.user.config.properties"),
    @PropertySource(ignoreResourceNotFound = true,
                    value = "file:///${app.config}")
})
public class TestConfig {

    @Autowired
    Environment env;

    @Value("${prop1}")
    String prop1;

    @Bean
    public BasicData bd1() {
        System.out.println(env.getProperty("prop1"));
        System.out.println(prop1);
        return new BasicData("Test");
    }

env.getProperty(String)按预期工作，但我虽然@Value注释也可能有效。

配置通过MVC初始化程序实例化，如下所示：

public class AppInitializer
        extends AbstractAnnotationConfigDispatcherServletInitializer {

    @Override
    protected Class<?>[] getRootConfigClasses() {
        return new Class[]{
            RootConfig.class,
            TestConfig.class,
            SecurityConfig.class
        };
    }

以前我会使用以下方法使用XML配置实现此目的：

<context:property-placeholder
    location="classpath:app.config.properties,classpath:app.user.config.properties,file:///${app.config}"
    ignore-resource-not-found="true"/>

Answer 1

@PropertySource的文档说明属性来源已添加到Environment。

 * Annotation providing a convenient and declarative mechanism for adding a
 * {@link org.springframework.core.env.PropertySource PropertySource} to Spring's
 * {@link org.springframework.core.env.Environment Environment}. To be used in
 * conjunction with @{@link Configuration} classes.

占位符的替换由BeanFactoryPostProcessor完成。这曾经是PropertyPlaceholderConfigurer，但自从Spring 3.1开始PropertySourcesPlaceholderConfigurer。我认为这是将这种类型的bean添加到上下文中的问题。其文档表明它针对Environment：

解决了占位符问题

 * Specialization of {@link org.springframework.beans.factory.config.PlaceholderConfigurerSupport
 * PlaceholderConfigurerSupport} that resolves ${...} placeholders within bean definition
 * property values and {@code @Value} annotations against the current Spring {@link
 * Environment} and its set of {@link PropertySources}.

Answer 2

管理解决方案。我将PropertySoure（s）移到RootConfig，展示了PropertySourcesPlaceholderConfigurer bean。

@PropertySources({
    @PropertySource(ignoreResourceNotFound = true,
                    value = "classpath:app.config.properties"),
    @PropertySource(ignoreResourceNotFound = true,
                    value = "classpath:app.user.config.properties"),
    @PropertySource(ignoreResourceNotFound = true,
                    value = "file:///${app.config}")
})
public class RootConfig {

    @Bean
    public static PropertySourcesPlaceholderConfigurer propertySourcesPlaceholderConfigurer() {
        return new PropertySourcesPlaceholderConfigurer();
    }

}

@PropertySource是否可以用于@Value的属性？

2 个答案: