java - 如何仅使用注释读取 Controller 中的属性文件？ Spring MVC

Question

如何仅使用注释读取 Controller 中的属性文件？

属性文件包含(env.properties):

 document.portal.path=http://flana.gost.com/service

Spring Controller :

@Controller
@RequestMapping("/kap/*")
@SessionAttributes({"user", "KapForm", "activity"})
public class KapController {
@Value("${document.portal.path}")
private String URL; 
}

没有做任何其他事情。在 XML 中，我们经常使用占位符，但我不知道如何在其中引入。所以我遇到了异常(exception)。

Injection of autowired dependencies failed; 

Answer 1

您可以通过两种方式实现它

选项 1

在配置类中放置@PropertySource并为PropertySourcesPlaceholderConfigurer定义一个bean，如下 -

@Configuration
@PropertySource("classpath:someFile.properties")
public class SampleConfig { 

    // other configs...

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

选项 2

在配置类中直接为PropertyPlaceholderConfigurer指定bean，并将属性文件的名称提供为ClassPathResource

@Configuration
public class SampleConfig {

    // other configs...

    @Bean
    public static PropertyPlaceholderConfigurer placeHolderConfigurer(){
      PropertyPlaceholderConfigurer placeHolderConfigurer = new PropertyPlaceholderConfigurer();
      ClassPathResource[] cpResources = new ClassPathResource[]
              { new ClassPathResource( "someFile.properties" ) };
      placeHolderConfigurer.setLocations(cpResources);
      placeHolderConfigurer.setIgnoreUnresolvablePlaceholders(true);
      return placeHolderConfigurer;
    }
}

请注意，占位符的 bean 定义必须是静态，如 java docs 所示。 (摘录如下)

Special consideration must be taken for @Bean methods that return Spring BeanFactoryPostProcessor (BFPP) types. Because BFPP objects must be instantiated very early in the container lifecycle, they can interfere with processing of annotations such as @Autowired, @Value, and @PostConstruct within @Configuration classes. To avoid these lifecycle issues, mark BFPP-returning @Bean methods as static.