在Spring Boot Application初始化之前讀取屬性

Question

我有這樣一種情況，從Spring程序運行之前從classpath:app.properties或classpath:presentation-api.properties讀取一個屬性，以設置幾個舊的配置文件，這將很有用。

所以會是這樣的：

@SpringBootApplication
@PropertySource({"classpath:app.properties", "classpath:various_other.properties"})
public class MainApp extends SpringBootServletInitializer {

   @Override
    protected SpringApplicationBuilder configure(SpringApplicationBuilder builder) {

        boolean legacyPropertyA = // might be set in classpath:app.properties or classpath:various_other.properties or not at all       
        boolean legacyPropertyB = // might be set in classpath:app.properties or classpath:various_other.properties or not at all

        if (legacyPropertyA) {
            builder.profiles("legacyProfileA");
        }
        if (legacyPropertyB) {
            builder.profiles("legacyProfileB");
        }

        return super.configure(builder);
    }
}

檢索legacyPropertyA和legacyPropertyB的最干凈方法是什么？

Answer 1

我認為您可以將@Value和@PostConstruct批注結合起來，以獲得更清潔的解決方案。 請看下面的例子：

@SpringBootApplication
@PropertySource({"classpath:application-one.properties", "classpath:application-two.properties"})
public class MyApplication extends SpringBootServletInitializer {

    @Value("${property.one}")
    private String propertyOne;

    @Value("${property.two}")
    private String propertyTwo;

    @Override
    protected SpringApplicationBuilder configure(SpringApplicationBuilder application) {
        return application.sources(MyApplication.class);
    }

    @PostConstruct
    public void initProperties() {
        System.out.println(propertyOne);
        System.out.println(propertyTwo);
    }
}

希望對您有所幫助。 請讓我知道您有任何問題。