spring 使用 @PropertySource 注释时未解析 @Value。如何配置 PropertySourcesPlaceholderConfigurer？
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@Value not resolved when using @PropertySource annotation. How to configure PropertySourcesPlaceholderConfigurer?
提问by matus
I have following configuration class:
我有以下配置类：
@Configuration
@PropertySource(name = "props", value = "classpath:/app-config.properties")
@ComponentScan("service")
public class AppConfig {
and I have service with property:
我有物业服务：
@Component
public class SomeService {
@Value("#{props['some.property']}") private String someProperty;
I receive error when I want to test the AppConfig configuration class with
当我想测试 AppConfig 配置类时收到错误
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'someService': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: private java.lang.String service.SomeService.someProperty; nested exception is org.springframework.beans.factory.BeanExpressionException: Expression parsing failed; nested exception is org.springframework.expression.spel.SpelEvaluationException: EL1008E:(pos 0): Field or property 'props' cannot be found on object of type 'org.springframework.beans.factory.config.BeanExpressionContext'
The issue is documented in SPR-8539
该问题记录在 SPR-8539 中
but anyway I cannot figure out how to configure PropertySourcesPlaceholderConfigurerto get it work.
但无论如何我无法弄清楚如何配置PropertySourcesPlaceholderConfigurer以使其工作。
Edit 1
编辑 1
This approach works well with xml configuration
这种方法适用于 xml 配置
<util:properties id="props" location="classpath:/app-config.properties" />
but I want to use java for configuration.
但我想使用 java 进行配置。
采纳答案by laffuste
If you use @PropertySource, properties have to be retrieved with:
如果您使用@PropertySource，则必须通过以下方式检索属性：
@Autowired
Environment env;
// ...
String subject = env.getProperty("mail.subject");
If you want to retrieve with @Value("${mail.subject}"), you have to register the prop placeholder by xml.
如果要使用@Value("${mail.subject}") 进行检索，则必须通过xml 注册prop 占位符。
回答by baybora.oren
as @cwash said;
正如@cwash 所说；
@Configuration
@PropertySource("classpath:/test-config.properties")
public class TestConfig {
@Value("${name}")
public String name;
//You need this
@Bean
public static PropertySourcesPlaceholderConfigurer propertySourcesPlaceholderConfigurer() {
return new PropertySourcesPlaceholderConfigurer();
}
}
回答by Sachchidanand Singh
I found the reason @valuewas not working for me is, @valuerequires PropertySourcesPlaceholderConfigurerinstead of a PropertyPlaceholderConfigurer. I did the same changes and it worked for me, I am using spring 4.0.3 release. I configured this using below code in my configuration file.
我发现@value对我不起作用的原因是，@value需要PropertySourcesPlaceholderConfigurer而不是PropertyPlaceholderConfigurer. 我做了相同的更改，它对我有用，我使用的是 spring 4.0.3 版本。我在配置文件中使用以下代码进行了配置。
@Bean
public static PropertySourcesPlaceholderConfigurer propertySourcesPlaceholderConfigurer() {
return new PropertySourcesPlaceholderConfigurer();
}
回答by cwash
Don't you need a method on your @Configuration class that returns PropertySourcesPlaceholderConfigurer, annotated @Bean and is static, to register any @PropertySource with Spring?
您是否不需要@Configuration 类上的方法来返回 PropertySourcesPlaceholderConfigurer、带注释的 @Bean 并且是静态的，以便向 Spring 注册任何 @PropertySource？
http://www.baeldung.com/2012/02/06/properties-with-spring/#java
http://www.baeldung.com/2012/02/06/properties-with-spring/#java
回答by dimitrisli
I had the very same problem. @PropertySourceis not playing well with @Value. A quick workaround is to have an XML configuration which you'll refer to it from your Spring Java Configuration using @ImportResourceas usual and that XML configuration file will include a single entry: <context:property-placeholder />(of course with the needed namespace ceremony). Without any other change @Valuewill inject properties in your @Configurationpojo.
我有同样的问题。@PropertySource玩得不好@Value。一个快速的解决方法是拥有一个 XML 配置，您将@ImportResource像往常一样使用它从 Spring Java 配置中引用它，并且该 XML 配置文件将包含一个条目：（<context:property-placeholder />当然还有所需的命名空间仪式）。没有任何其他更改@Value将在您的@Configurationpojo 中注入属性。
回答by Gowtham
This can also be configured in java this way
这也可以在java中这样配置
@Bean
public static PropertySourcesPlaceholderConfigurer properties() {
PropertySourcesPlaceholderConfigurer configurer = new PropertySourcesPlaceholderConfigurer();
configurer.setIgnoreUnresolvablePlaceholders(true);
configurer.setIgnoreResourceNotFound(true);
return configurer;
}
回答by NimChimpsky
That looks mighty complicated, can't you just do
这看起来很复杂，你就不能做
<context:property-placeholder location="classpath:some.properties" ignore-unresolvable="true"/>
then in code reference:
然后在代码参考中：
@Value("${myProperty}")
private String myString;
@Value("${myProperty.two}")
private String myStringTwo;
where some.properties looks something like this
some.properties 看起来像这样
myProperty = whatever
myProperty.two = something else\
that consists of multiline string
For java based config you can do this
对于基于 Java 的配置，您可以执行此操作
@Configuration
@PropertySource(value="classpath:some.properties")
public class SomeService {
And then just inject using @valueas before
然后@value像以前一样注入使用
回答by Artem Shitov
The thing is: as far as I get it, <util:propertes id="id" location="loc"/>, is just a shorthand for
问题是：据我所知，<util:propertes id="id" location="loc"/>，只是一个简写
<bean id="id" class="org.springframework.beans.factory.config.PropertiesFactoryBean">
<property name="location" value="loc"/>
</bean>
(see documentation of util:properties). Thus, when you use util:properties, a standalone bean is created.
（请参阅util:properties 的文档）。因此，当您使用 util:properties 时，会创建一个独立的 bean。
@PropertySource, on the other hand, as documentation says is an
另一方面，@PropertySource，正如文档所说的那样
annotation providing a convenient and declarative mechanism for adding a PropertySource to Spring's Environment'.
注释为将 PropertySource 添加到 Spring 的环境提供了一种方便的声明机制。
(see @PropertySource doc). So it doesn't create any bean.
（请参阅@PropertySource 文档）。所以它不会创建任何bean。
Then "#{a['something']}" is a SpEL expression (see SpEL), that means "get something from bean'a'". When util:properties is used, the bean exists and the expression is meaningful, but when @PropertySource is used, there is no actual bean and the expression is meaningless.
然后 "#{a['something']}" 是一个 SpEL 表达式（参见SpEL），这意味着“从bean'a' 中获取一些东西”。当使用 util:properties 时，bean 存在并且表达式是有意义的，但是当使用 @PropertySource 时，没有实际的 bean 并且表达式没有意义。
You can workaround this either by using XML (which is the best way, I think) or by issuing a PropertiesFactoryBean by yourself, declaring it as a normal @Bean.
您可以通过使用 XML（我认为这是最好的方法）或自己发布 PropertiesFactoryBean 来解决此问题，将其声明为普通的 @Bean。
回答by Jan Bodnar
Since Spring 4.3 RC2 using PropertySourcesPlaceholderConfigureror <context:property-placeholder>is not needed anymore. We can use directly @PropertySourcewith @Value. See this Spring framework ticket
由于 Spring 4.3 RC2 使用PropertySourcesPlaceholderConfigurer或<context:property-placeholder>不再需要。我们可以直接@PropertySource与@Value. 请参阅此Spring 框架票证
I have created a test application with Spring 5.1.3.RELEASE.
The application.propertiescontains two pairs:
我用 Spring 5.1.3.RELEASE 创建了一个测试应用程序。在application.properties包括两对：
app.name=My application
app.version=1.1
The AppConfigloads the properties via @PropertySource.
通过AppConfig加载属性@PropertySource。
package com.zetcode.config;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.PropertySource;
@Configuration
@PropertySource(value = "application.properties", ignoreResourceNotFound = true)
public class AppConfig {
}
The Applicationinjects the properties via @Valueand uses them.
通过Application注入属性@Value并使用它们。
package com.zetcode;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.context.annotation.ComponentScan;
@ComponentScan(basePackages = "com.zetcode")
public class Application {
private static final Logger logger = LoggerFactory.getLogger(Application.class);
@Value("${app.name}")
private String appName;
@Value("${app.version}")
private String appVersion;
public static void main(String[] args) {
var ctx = new AnnotationConfigApplicationContext(Application.class);
var app = ctx.getBean(Application.class);
app.run();
ctx.close();
}
public void run() {
logger.info("Application name: {}", appName);
logger.info("Application version: {}", appVersion);
}
}
The output is:
输出是：
$ mvn -q exec:java
22:20:10.894 [com.zetcode.Application.main()] INFO com.zetcode.Application - Application name: My application
22:20:10.894 [com.zetcode.Application.main()] INFO com.zetcode.Application - Application version: 1.1
回答by Smart Coder
In my case, depends-on="bean1" was within property-placeholder was causing the issue. I removed that dependency and used @PostConstruct to achieve the same original functionality and was able to read the new values too.
在我的情况下，depends-on="bean1" 在属性占位符内导致了问题。我删除了该依赖项并使用 @PostConstruct 来实现相同的原始功能，并且也能够读取新值。
