Java Spring Boot application.properties 值未填充
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Spring Boot application.properties value not populating
提问by grahamrb
I have a very simple Spring Boot app that I'm trying to get working with some externalised configuration. I've tried to follow the information on the spring boot documentationhowever I'm hitting a road block.
我有一个非常简单的 Spring Boot 应用程序，我正在尝试使用一些外部化配置。我试图遵循spring 引导文档中的信息，但是我遇到了障碍。
When I run the app below the external configuration in the application.properties file does not get populated into the variable within the bean. I'm sure I'm doing something stupid, thanks for any suggestions.
当我在 application.properties 文件中的外部配置下运行应用程序时，不会填充到 bean 中的变量中。我确定我在做一些愚蠢的事情，感谢您的任何建议。
MyBean.java(located in /src/main/java/foo/bar/)
MyBean.java（位于 /src/main/java/foo/bar/）
package foo.bar;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.stereotype.Component;
@Component
public class MyBean {
@Value("${some.prop}")
private String prop;
public MyBean() {
System.out.println("================== " + prop + "================== ");
}
}
Application.java(located in /src/main/java/foo/)
Application.java（位于/src/main/java/foo/）
package foo;
import foo.bar.MyBean;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.boot.SpringApplication;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
@Configuration
@ComponentScan
@EnableAutoConfiguration
public class Application {
@Autowired
private MyBean myBean;
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
}
application.properties (located in /src/main/resources/)
application.properties（位于/src/main/resources/）
some.prop=aabbcc
Log outputwhen executing the Spring Boot app:
执行 Spring Boot 应用程序时的日志输出：
grb-macbook-pro:properties-test-app grahamrb$ java -jar ./build/libs/properties-test-app-0.1.0.jar
. ____ _ __ _ _
/\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
\/ ___)| |_)| | | | | || (_| | ) ) ) )
' |____| .__|_| |_|_| |_\__, | / / / /
=========|_|==============|___/=/_/_/_/
:: Spring Boot :: (v1.1.5.RELEASE)
2014-09-10 21:28:42.149 INFO 16554 --- [ main] foo.Application : Starting Application on grb-macbook-pro.local with PID 16554 (/Users/grahamrb/Dropbox/dev-projects/spring-apps/properties-test-app/build/libs/properties-test-app-0.1.0.jar started by grahamrb in /Users/grahamrb/Dropbox/dev-projects/spring-apps/properties-test-app)
2014-09-10 21:28:42.196 INFO 16554 --- [ main] ationConfigEmbeddedWebApplicationContext : Refreshing org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@67e38ec8: startup date [Wed Sep 10 21:28:42 EST 2014]; root of context hierarchy
2014-09-10 21:28:42.828 INFO 16554 --- [ main] o.s.b.f.s.DefaultListableBeanFactory : Overriding bean definition for bean 'beanNameViewResolver': replacing [Root bean: class [null]; scope=; abstract=false; lazyInit=false; autowireMode=3; dependencyCheck=0; autowireCandidate=true; primary=false; factoryBeanName=org.springframework.boot.autoconfigure.web.ErrorMvcAutoConfiguration$WhitelabelErrorViewConfiguration; factoryMethodName=beanNameViewResolver; initMethodName=null; destroyMethodName=(inferred); defined in class path resource [org/springframework/boot/autoconfigure/web/ErrorMvcAutoConfiguration$WhitelabelErrorViewConfiguration.class]] with [Root bean: class [null]; scope=; abstract=false; lazyInit=false; autowireMode=3; dependencyCheck=0; autowireCandidate=true; primary=false; factoryBeanName=org.springframework.boot.autoconfigure.web.WebMvcAutoConfiguration$WebMvcAutoConfigurationAdapter; factoryMethodName=beanNameViewResolver; initMethodName=null; destroyMethodName=(inferred); defined in class path resource [org/springframework/boot/autoconfigure/web/WebMvcAutoConfiguration$WebMvcAutoConfigurationAdapter.class]]
2014-09-10 21:28:43.592 INFO 16554 --- [ main] .t.TomcatEmbeddedServletContainerFactory : Server initialized with port: 8080
2014-09-10 21:28:43.784 INFO 16554 --- [ main] o.apache.catalina.core.StandardService : Starting service Tomcat
2014-09-10 21:28:43.785 INFO 16554 --- [ main] org.apache.catalina.core.StandardEngine : Starting Servlet Engine: Apache Tomcat/7.0.54
2014-09-10 21:28:43.889 INFO 16554 --- [ost-startStop-1] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring embedded WebApplicationContext
2014-09-10 21:28:43.889 INFO 16554 --- [ost-startStop-1] o.s.web.context.ContextLoader : Root WebApplicationContext: initialization completed in 1695 ms
2014-09-10 21:28:44.391 INFO 16554 --- [ost-startStop-1] o.s.b.c.e.ServletRegistrationBean : Mapping servlet: 'dispatcherServlet' to [/]
2014-09-10 21:28:44.393 INFO 16554 --- [ost-startStop-1] o.s.b.c.embedded.FilterRegistrationBean : Mapping filter: 'hiddenHttpMethodFilter' to: [/*]
================== null==================
2014-09-10 21:28:44.606 INFO 16554 --- [ main] o.s.w.s.handler.SimpleUrlHandlerMapping : Mapped URL path [/**/favicon.ico] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2014-09-10 21:28:44.679 INFO 16554 --- [ main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/error],methods=[],params=[],headers=[],consumes=[],produces=[],custom=[]}" onto public org.springframework.http.ResponseEntity<java.util.Map<java.lang.String, java.lang.Object>> org.springframework.boot.autoconfigure.web.BasicErrorController.error(javax.servlet.http.HttpServletRequest)
2014-09-10 21:28:44.679 INFO 16554 --- [ main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/error],methods=[],params=[],headers=[],consumes=[],produces=[text/html],custom=[]}" onto public org.springframework.web.servlet.ModelAndView org.springframework.boot.autoconfigure.web.BasicErrorController.errorHtml(javax.servlet.http.HttpServletRequest)
2014-09-10 21:28:44.716 INFO 16554 --- [ main] o.s.w.s.handler.SimpleUrlHandlerMapping : Mapped URL path [/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2014-09-10 21:28:44.716 INFO 16554 --- [ main] o.s.w.s.handler.SimpleUrlHandlerMapping : Mapped URL path [/webjars/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2014-09-10 21:28:44.902 INFO 16554 --- [ main] o.s.j.e.a.AnnotationMBeanExporter : Registering beans for JMX exposure on startup
2014-09-10 21:28:44.963 INFO 16554 --- [ main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat started on port(s): 8080/http
2014-09-10 21:28:44.965 INFO 16554 --- [ main] foo.Application : Started Application in 3.316 seconds (JVM running for 3.822)
^C2014-09-10 21:28:54.223 INFO 16554 --- [ Thread-2] ationConfigEmbeddedWebApplicationContext : Closing org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@67e38ec8: startup date [Wed Sep 10 21:28:42 EST 2014]; root of context hierarchy
2014-09-10 21:28:54.225 INFO 16554 --- [ Thread-2] o.s.j.e.a.AnnotationMBeanExporter : Unregistering JMX-exposed beans on shutdown
采纳答案by geoand
The way you are performing the injection of the property will not work, because the injection is done after the constructor is called.
您执行属性注入的方式将不起作用，因为注入是在调用构造函数之后完成的。
You need to do one of the following:
您需要执行以下操作之一：
Better solution
更好的解决方案
@Component
public class MyBean {
private final String prop;
@Autowired
public MyBean(@Value("${some.prop}") String prop) {
this.prop = prop;
System.out.println("================== " + prop + "================== ");
}
}
Solution that will work but is less testable and slightly less readable
可行的解决方案，但可测试性和可读性稍差
@Component
public class MyBean {
@Value("${some.prop}")
private String prop;
public MyBean() {
}
@PostConstruct
public void init() {
System.out.println("================== " + prop + "================== ");
}
}
Also note that is not Spring Boot specific but applies to any Spring application
另请注意，这不是 Spring Boot 特定的，而是适用于任何 Spring 应用程序
回答by Amit Kr
The user "geoand" is right in pointing out the reasons here and giving a solution. But a better approach is to encapsulate your configuration into a separate class, say SystemContiguration java class and then inject this class into what ever services you want to use those fields.
用户“geoand”在这里指出原因并给出解决方案是正确的。但是更好的方法是将您的配置封装到一个单独的类中，比如 SystemContiguration java 类，然后将该类注入到您想要使用这些字段的任何服务中。
Your current way(@grahamrb) of reading config values directly into services is error prone and would cause refactoring headaches if config setting name is changed.
您当前将配置值直接读取到服务中的方式 (@grahamrb) 容易出错，如果更改配置设置名称，则会导致重构问题。
回答by Raj Mohamad
Actually, For me below works fine.
实际上，下面对我来说效果很好。
@Component
public class MyBean {
public static String prop;
@Value("${some.prop}")
public void setProp(String prop) {
this.prop= prop;
}
public MyBean() {
}
@PostConstruct
public void init() {
System.out.println("================== " + prop + "================== ");
}
}
}
Now whereever i want, just invoke
现在无论我想要什么，只要调用
MyBean.prop
MyBean.prop
it will return value.
它将返回值。
回答by leeyuiwah
This answer may or may not be applicable to your case ... Once I had a similar symptom and I double checked my code many times and all looked good but the @Valuesetting was still not taking effect. And then after doing File > Invalidate Cache / Restartwith my IntelliJ(my IDE), the problem went away ...
这个答案可能适用于您的情况，也可能不适用于您的情况......一旦我有类似的症状，我多次检查了我的代码，一切看起来都很好，但@Value设置仍然没有生效。然后在File > Invalidate Cache / Restart使用我的IntelliJ（我的 IDE）之后，问题就消失了......
This is very easy to try so may be worth a shot
这很容易尝试，所以值得一试
回答by ramakotireddy nagireddy
Using Environment class we can get application. Properties values
使用 Environment 类我们可以获得应用程序。属性值
@Autowired,
@自动连线，
private Environment env;
and access using
并使用访问
String password =env.getProperty(your property key);
回答by Fazle Subhan
follow these steps. 1:- create your configuration class like below you can see
按着这些次序。1:- 创建您的配置类，如下所示，您可以看到
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.beans.factory.annotation.Value;
@Configuration
public class YourConfiguration{
// passing the key which you set in application.properties
@Value("${some.pro}")
private String somePro;
// getting the value from that key which you set in application.properties
@Bean
public String getsomePro() {
return somePro;
}
}
2:- when you have a configuration class then inject in the variable from a configuration where you need.
2:- 当你有一个配置类时，然后从你需要的配置中注入变量。
@Component
public class YourService {
@Autowired
private String getsomePro;
// now you have a value in getsomePro variable automatically.
}
回答by Janac Meena
If you're working in a large multi-module project, with several different application.propertiesfiles, then try adding your value to the parentproject's property file.
如果您正在处理包含多个不同application.properties文件的大型多模块项目，请尝试将您的值添加到父项目的属性文件中。
If you are unsure which is your parent project, check your project's pom.xmlfile, for a <parent>tag.
如果您不确定哪个是您的父项目，请检查您的项目pom.xml文件以获取<parent>标签。
This solved the issue for me.
这为我解决了这个问题。
