java - Spring Boot 不会从 application.yml 中选取值

Question

我正在使用 spring-boot-starter-web 最新版本 2.2.6.RELEASE。但我的应用程序总是为带有 @value 注释的变量返回 null。

我的build.gradle，

plugins {
  id 'com.google.cloud.tools.jib' version '2.1.0'
  id 'org.springframework.boot' version '2.2.6.RELEASE'
  id 'io.spring.dependency-management' version '1.0.8.RELEASE'
  id 'java'
  id 'eclipse'
  id 'idea'
  id 'maven-publish'
}

jar {
    archiveBaseName = 'my-project'
    project.version =  '1.0.0'
}

repositories {
    jcenter()
    mavenCentral()
    mavenLocal()
}

sourceCompatibility = JavaVersion.VERSION_1_8
targetCompatibility = JavaVersion.VERSION_1_8

dependencies {
    implementation group: 'org.apache.commons', name: 'commons-lang3', version: '+'
    implementation('org.springframework.boot:spring-boot-starter-web:+') {
        exclude module: 'spring-boot-starter-tomcat'
    }

    implementation("org.springframework.boot:spring-boot-starter-jetty:+")
    implementation group: 'io.springfox', name: 'springfox-swagger2', version: '2.8.0'
    implementation group: 'io.springfox', name: 'springfox-swagger-ui', version: '2.8.0'
    implementation group: 'io.kubernetes', name: 'client-java', version: '+'
    implementation group: 'com.google.cloud', name: 'google-cloud-dataproc', version: '+'

    implementation(project(':my-project-1')) {
        exclude group: 'org.yaml'
    }

    implementation project(':my-project2')
}

tasks.withType(JavaCompile) {
    options.compilerArgs << '-Xlint:unchecked'
    options.deprecation = true
}

我的Java代码，

@Component
public class MyClass {

    @Value("${dataproc.host}")
    private static String dataprocEndpoint;

我的应用程序.yml

dataproc:
  host: dataproc.googleapis.com:443

我的应用程序.java，

@SpringBootApplication
@EnableSwagger2
@Configuration
public class Application {

    private static final Logger LOGGER = LoggerFactory.getLogger(Application.class);
    private transient String PATTERNS_TO_HIDE = "^/(?!error|autoconfig|beans|profile|info|health|pause|env|refresh|resume|restart|actuator|dump|mappings|trace|metrics|heapdump|archaius|configprops|features|liquibase|loggers|auditevents).*$";

    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }

    @Bean
    public Docket api() {
        ApiInfo apiInfo = new ApiInfoBuilder().license("Proprietary").title("My Application")
                .description("My Application").build();

        return new Docket(DocumentationType.SWAGGER_2).select().apis(RequestHandlerSelectors.any())
                .paths(PathSelectors.regex(PATTERNS_TO_HIDE)).build().pathMapping("/").apiInfo(apiInfo)
                .useDefaultResponseMessages(false)
                .globalResponseMessage(RequestMethod.GET, newArrayList(new ResponseMessageBuilder().code(500)
                        .message("500 message").responseModel(new ModelRef("Error")).build()));
    }
}

当我启动服务器时总是返回null，dataprocEndpoint:空

我在这里缺少什么配置？

请在此提供您的意见。

Answer 1

1. 将您的属性用引号引起来:

   数据处理: 主机:'dataproc.googleapis.com:443'

Yml 处理器将您的配置属性名称解释为 dataproc.host.dataproc.googleapis.com.443

从字段声明中删除静态。

@Value("${dataproc.host}")私有(private)字符串dataprocEndpoint;

静态字段通过类加载进行初始化。 Spring bean 后处理器无法在这么早的阶段注入(inject)值。如果您想向静态字段注入(inject)值，您可以使用 setter 注入(inject)。

引用号https://mkyong.com/spring/spring-inject-a-value-into-static-variables/