java - Spring Boot @ConfigurationProperties 不从环境中检索属性

Question

我正在使用 Spring Boot 1.2.1 并尝试创建一个带有验证的 @ConfigurationProperties bean，如下所示:

package com.sampleapp;

import java.net.URL;

import javax.validation.constraints.NotNull;

import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.stereotype.Component;

@Component
@ConfigurationProperties
public class SampleAppProperties {
    @NotNull
    private URL url;

    public URL getUrl() {
        return url;
    }
}

引导应用程序的类是:

package com.sampleapp;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.context.EnvironmentAware;
import org.springframework.core.env.Environment;

@SpringBootApplication
@EnableConfigurationProperties
public class SampleApplication implements EnvironmentAware {
    private static Logger LOGGER = LoggerFactory.getLogger(SampleApplication.class);

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

    @Override
    public void setEnvironment(Environment environment) {
        LOGGER.info("URL = {}", environment.getRequiredProperty("url"));
    }
}

当我尝试启动此应用程序时，我收到以下异常堆栈:

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'sampleAppProperties': Could not bind properties to [unknown] (target=, ignoreInvalidFields=false, ignoreUnknownFields=true, ignoreNestedProperties=false); nested exception is org.springframework.validation.BindException: org.springframework.validation.BeanPropertyBindingResult: 1 errors
Field error in object 'target' on field 'url': rejected value [null]; codes [NotNull.target.url,NotNull.url,NotNull.java.net.URL,NotNull]; arguments [org.springframework.context.support.DefaultMessageSourceResolvable: codes [target.url,url]; arguments []; default message [url]]; default message [may not be null]
    at org.springframework.boot.context.properties.ConfigurationPropertiesBindingPostProcessor.postProcessBeforeInitialization(ConfigurationPropertiesBindingPostProcessor.java:303)
    at org.springframework.boot.context.properties.ConfigurationPropertiesBindingPostProcessor.postProcessBeforeInitialization(ConfigurationPropertiesBindingPostProcessor.java:250)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyBeanPostProcessorsBeforeInitialization(AbstractAutowireCapableBeanFactory.java:408)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1558)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:539)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:476)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:303)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:299)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:194)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:762)
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:757)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:480)
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:691)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:321)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:961)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:950)
    at com.sampleapp.SampleApplication.main(SampleApplication.java:17)
Caused by: org.springframework.validation.BindException: org.springframework.validation.BeanPropertyBindingResult: 1 errors
Field error in object 'target' on field 'url': rejected value [null]; codes [NotNull.target.url,NotNull.url,NotNull.java.net.URL,NotNull]; arguments [org.springframework.context.support.DefaultMessageSourceResolvable: codes [target.url,url]; arguments []; default message [url]]; default message [may not be null]
    at org.springframework.boot.bind.PropertiesConfigurationFactory.validate(PropertiesConfigurationFactory.java:294)
    at org.springframework.boot.bind.PropertiesConfigurationFactory.doBindPropertiesToTarget(PropertiesConfigurationFactory.java:253)
    at org.springframework.boot.bind.PropertiesConfigurationFactory.bindPropertiesToTarget(PropertiesConfigurationFactory.java:225)
    at org.springframework.boot.context.properties.ConfigurationPropertiesBindingPostProcessor.postProcessBeforeInitialization(ConfigurationPropertiesBindingPostProcessor.java:296)
    ... 17 common frames omitted

正如您在上面的 setEnvironment 方法中看到的那样，我正在记录 url 属性以验证它是 Environment 的一部分并且它在异常之前显示:

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::        (v1.2.1.RELEASE)

2015-02-12 12:32:01.384  INFO 5608 --- [           main] c.s.SampleApplication                    : Starting SampleApplication on VDDK03E-14FB6E5 with PID 5608 (D:\projects\onboarding-parser\target\classes started by .....
2015-02-12 12:32:01.509  INFO 5608 --- [           main] s.c.a.AnnotationConfigApplicationContext : Refreshing org.springframework.context.annotation.AnnotationConfigApplicationContext@3252ac20: startup date [Thu Feb 12 12:32:01 EST 2015]; root of context hierarchy
2015-02-12 12:32:03.040  INFO 5608 --- [           main] c.s.SampleApplication                    : URL = http://www.joe.com
2015-02-12 12:32:03.378 ERROR 5608 --- [           main] o.s.b.b.PropertiesConfigurationFactory   : Properties configuration failed validation
2015-02-12 12:32:03.378 ERROR 5608 --- [           main] o.s.b.b.PropertiesConfigurationFactory   : Field error in object 'target' on field 'url': rejected value [null]; codes [NotNull.target.url,NotNull.url,NotNull.java.net.URL,NotNull]; arguments [org.springframework.context.support.DefaultMessageSourceResolvable: codes [target.url,url]; arguments []; default message [url]]; default message [may not be null]
2015-02-12 12:32:03.394  WARN 5608 --- [           main] s.c.a.AnnotationConfigApplicationContext : Exception encountered during context initialization - cancelling refresh attempt

url 属性是从 src/main/resources 中的 application.properties 文件中提取的。文件内容为:

url=http://www.joe.com

Answer 1

您的 bean 中没有 setter 。添加二传手。