Java 运行基于Spring的应用程序时如何解析占位符？

同事们，我有基于java的Spring配置：

@Configuration
@EnableTransactionManagement
@ComponentScan (basePackages = {"com.abc.dirint"})
@PropertySource("classpath:/settings/${env}/dir.properties")
@EnableScheduling
public class DirConfig {

    private static final Logger log = LoggerFactory.getLogger(DirConfig.class);

    @Autowired
    private Environment environment;

     @Bean
        public static PropertySourcesPlaceholderConfigurer propertyConfigInDev() throws IOException {
            PropertySourcesPlaceholderConfigurer propertySourcesPlaceholderConfigurer = new PropertySourcesPlaceholderConfigurer();
    propertySourcesPlaceholderConfigurer.setIgnoreUnresolvablePlaceholders(true);
            return propertySourcesPlaceholderConfigurer;
        }


        /*Beans follow...*/ 

        }

当我执行

mvncleanpackage-Denv=dev

时，它运行测试并构建项目，没有任何错误

现在我想运行编译过的jar。 我执行

java-jar dir-integration-1.2-SNAPSHOT.jar-Denv=dev

，程序失败（这是预期的），下一个堆栈跟踪：

Exception in thread "main" org.springframework.beans.factory.BeanDefinitionStoreException: Failed to parse configuration class [com.abc.dirint.DirConfig]; nested exception is java.lang.IllegalArgumentException: Could not resolve placeholder 'env' in string value "classpath:/settings/${env}/dir.properties"
        at org.springframework.context.annotation.ConfigurationClassParser.parse(ConfigurationClassParser.java:180)

Wnen我运行

$java-jar dir-integration-1.2-SNAPSHOT.jar--env=dev

结果如下：

Exception in thread "main" org.springframework.beans.factory.BeanDefinitionStoreException: Failed to parse configuration class [com.abc.dirint.DirConfig]; nested exception is java.lang.IllegalArgumentException: Could not resolve placeholder 'env' in string value "classpath:/settings/${env}/dir.properties"
        at org.springframework.context.annotation.ConfigurationClassParser.parse(ConfigurationClassParser.java:180)
        at org.springframework.context.annotation.ConfigurationClassPostProcessor.processConfigBeanDefinitions(ConfigurationClassPostProcessor.java:308)
        at org.springframework.context.annotation.ConfigurationClassPostProcessor.postProcessBeanDefinitionRegistry(ConfigurationClassPostProcessor.java:228)
        at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanDefinitionRegistryPostProcessors(PostProcessorRegistrationDelegate.java:270)
        at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(PostProcessorRegistrationDelegate.java:93)
        at org.springframework.context.support.AbstractApplicationContext.invokeBeanFactoryPostProcessors(AbstractApplicationContext.java:686)
        at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:524)
        at org.springframework.context.annotation.AnnotationConfigApplicationContext.<init>(AnnotationConfigApplicationContext.java:84)
        at com.abc.dirint.AdApp.main(AdApp.java:19) Caused by: java.lang.IllegalArgumentException: Could not resolve placeholder 'env' in string value "classpath:/settings/${env}/dir.properties"
        at org.springframework.util.PropertyPlaceholderHelper.parseStringValue(PropertyPlaceholderHelper.java:174)
        at org.springframework.util.PropertyPlaceholderHelper.replacePlaceholders(PropertyPlaceholderHelper.java:126)
        at org.springframework.core.env.AbstractPropertyResolver.doResolvePlaceholders(AbstractPropertyResolver.java:236)
        at org.springframework.core.env.AbstractPropertyResolver.resolveRequiredPlaceholders(AbstractPropertyResolver.java:210)
        at org.springframework.core.env.AbstractEnvironment.resolveRequiredPlaceholders(AbstractEnvironment.java:571)
        at org.springframework.context.annotation.ConfigurationClassParser.processPropertySource(ConfigurationClassParser.java:379)
        at org.springframework.context.annotation.ConfigurationClassParser.doProcessConfigurationClass(ConfigurationClassParser.java:

线程“main”org.springframework.beans.factory.BeanDefinitionStoreException中的异常：未能解析配置类[com.abc.dirint.DirConfig]；嵌套异常为java.lang.IllegalArgumentException:无法解析字符串值“classpath:/settings/${env}/dir.properties”中的占位符“env” 位于org.springframework.context.annotation.ConfigurationClassParser.parse（ConfigurationClassParser.java:180） 位于org.springframework.context.annotation.ConfigurationClassPostProcessor.processConfigBeanDefinitions（ConfigurationClassPostProcessor.java:308） 位于org.springframework.context.annotation.ConfigurationClassPostProcessor.postProcessBeanDefinitionRegistry（ConfigurationClassPostProcessor.java:228） 位于org.springframework.context.support.postprocessorregistrationlegate.invokeBeanDefinitionRegistryPostProcessors（postprocessorregistrationlegate.java:270） 位于org.springframework.context.support.postprocessorregistrationlegate.invokeBeanFactoryPostProcessors（postprocessorregistrationlegate.java:93） 位于org.springframework.context.support.AbstractApplicationContext.invokeBeanFactoryPostProcessors（AbstractApplicationContext.java:686） 位于org.springframework.context.support.AbstractApplicationContext.refresh（AbstractApplicationContext.java:524） 位于org.springframework.context.annotation.AnnotationConfigApplicationContext。（AnnotationConfigApplicationContext.java:84） 在com.abc.dirint.AdApp.main（AdApp.java:19）上，由于以下原因导致：java.lang.IllegalArgumentException:无法解析字符串值“classpath:/settings/${env}/dir.properties”中的占位符“env” 位于org.springframework.util.PropertyPlaceholderHelper.parseStringValue（PropertyPlaceholderHelper.java:174） 位于org.springframework.util.PropertyPlaceholderHelper.ReplacePlaceHolderHelper（PropertyPlaceholderHelper.java:126） 位于org.springframework.core.env.AbstractPropertyResolver.doResolvePlaceholders（AbstractPropertyResolver.java:236） 位于org.springframework.core.env.AbstractPropertyResolver.resolveRequiredPlaceholders（AbstractPropertyResolver.java:210） 位于org.springframework.core.env.AbstractEnvironment.resolveRequiredPlaceholders（AbstractEnvironment.java:571） 位于org.springframework.context.annotation.ConfigurationClassParser.processPropertySource（ConfigurationClassParser.java:379） 位于org.springframework.context.annotation.ConfigurationClassParser.doProcessConfigurationClass（ConfigurationClassParser.java:

---

在应用程序运行期间，如何从指定的属性文件接收属性？

从

java-h

Usage: java [-options] class [args...]
           (to execute a class)
   or  java [-options] -jar jarfile [args...]
           (to execute a jar file)
where options include:
...
    -D<name>=<value>
                  set a system property

用法：java[-options]类[args…] （执行一个类） 或java[-options]-jar jarfile[args…] （执行jar文件） 其中包括： ... -D= 设置系统属性 因此，使用提供的系统属性运行jar的正确命令应该是

java-Denv=dev-jar dir-integration-1.2-SNAPSHOT.jar

---

而且，您应该知道，使用

mvn…-Denv=dev

vs

java-Denv=dev…

是两件完全不同的事情

使用

mvn

，占位符替换在编译时发生，这意味着最终的jar将包含

@PropertySource（“classpath:/settings/dev/dir.properties”）

---

但是，您的第二种方法是将占位符保留在已编译类中，并依靠Spring在运行时执行替换。这可能会帮助您：尝试运行为：java-Denv=dev-jar dir-integration-1.2-SNAPSHOT.jar