如何在实现Condition/ConfigurationCondition接口的类中使用@Value或Environment [英] How get working @Value or Environment in a class implementing the Condition/ConfigurationCondition interfaces
问题描述
我仅使用JavaConfig.
I am working with only JavaConfig.
我有以下声明:
@Bean
public static PropertySourcesPlaceholderConfigurer propertyPlaceholderConfigurer() {
return new PropertySourcesPlaceholderConfigurer();
}
根据以下文章，它对于JavaConfig是必需的: Spring 3.2 @value纯Java配置的注解不起作用，但是Environment.getProperty起作用
it is mandatory for JavaConfig according with the following post: Spring 3.2 @value annotation with pure java configuration does not work, but Environment.getProperty works
以下代码可以完美运行(出于测试目的，许多@Values都可以实现):
The following code works perfect (many @Values by testing purposes):
@Configuration
public class ActiveMQServerConfiguration {
@Value("${localhost.address}")
private String localHost;
@Value("${remotehost.address}")
private String remoteHost;
@Value("${localhost.port}")
private Integer localPort;
@Value("${remotehost.port}")
private Integer remotePort;
@Bean(name="connectionFactory")
@Conditional(LocalHostStatusCondition.class)
public ActiveMQConnectionFactory localConnectionFactory(
@Value("${localhost.protocol}") String protocol,
@Value("${localhost.address}") String host,
@Value("${localhost.port}") String port ){
System.out.println("protocol: "+protocol);
System.out.println("host: "+host);
System.out.println("port: "+port);
System.out.println("localHost: "+localHost);
System.out.println("localPort: "+localPort);
System.out.println("remoteHost: "+remoteHost);
System.out.println("remotePort: "+remotePort);
我可以在控制台/终端中看到
I can see in the console/terminal
Alpha
protocol: tcp
host: 127.0.0.1
port: 61616
localHost: 127.0.0.1
localPort: 61616
remoteHost: 192.168.1.34
remotePort: 61616
但是以下内容无法按预期进行:
But the following does not works how expected:
public class LocalHostStatusCondition implements Condition {
private static final Logger logger = LoggerFactory.getLogger(LocalHostStatusCondition.class);
@Value("${localhost.address}")
private String localHost;
@Value("${remotehost.address}")
private String remoteHost;
@Value("${localhost.port}")
private Integer localPort;
@Value("${remotehost.port}")
private Integer remotePort;
@Autowired
private Environment environment;
@Override
public boolean matches(ConditionContext context, AnnotatedTypeMetadata metadata) {
logger.info("LocalHostStatusCondition...");
System.out.println("localHost: "+localHost);
System.out.println("localPort: "+localPort);
System.out.println("remoteHost: "+remoteHost);
System.out.println("remotePort: "+remotePort);
System.out.println("Env..." + environment.getProperty("localhost.address", String.class) );
实际上是相同的，甚至可以在环境
Practically the same and even working with Environment
输出为:
测试版
localHost: null
localPort: null
remoteHost: null
remotePort: null
[WARNING]
java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:483)
at org.codehaus.mojo.exec.ExecJavaMojo$1.run(ExecJavaMojo.java:293)
at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.NullPointerException
at com.manuel.jordan.infrastructure.support.LocalHostStatusCondition.matches(LocalHostStatusCondition.java:42)
根据
条件必须遵循与BeanFactoryPostProcessor相同的限制，并注意切勿与Bean实例进行交互.要更精细地控制与@Configuration Bean交互的条件，请考虑 ConfigurationCondition 接口.
关于 ConfigurationCondition 我已经阅读了何时还要使用Spring @ConfigurationCondition和@Condition吗? 我已编辑以下内容: 如果我使用: 但是控制台/终端没有显示有关正在运行的句子的任何信息，我的意思是System.out没有打印出来(我不了解这种奇怪的行为). but the console/terminal does not show nothing about the sentences working, I mean, System.out are not printing (I don't understand about this weird behaviour). 我该如何解决? 我需要工作@Value或Environment，目的是让应用程序知道是否应该连接到本地或远程ActiveMQ服务器. I need have working @Value or Environment, it with the purpose to let know the application if should connect to a local or remote ActiveMQ server. 是的，我已阅读以下内容:
如何延迟对Spring @Conditional的评估配置注释?
似乎没有解决办法…… And yes, I have read the following:
How do I delay evaluation of a Spring @Conditional configuration annotation?
seems there is no solution… 谢谢 您拥有 Spring采用您指定的 Spring takes the 如果需要，可以从 You can retrieve the 这篇关于如何在实现Condition/ConfigurationCondition接口的类中使用@Value或Environment的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！public class LocalHostStatusCondition implements ConfigurationCondition {
…
@Override
public ConfigurationPhase getConfigurationPhase() {
return ConfigurationPhase.PARSE_CONFIGURATION;
}
推荐答案
@Conditional(LocalHostStatusCondition.class)
Class类型，并将其实例化以使用其matches方法.它不会将实例视为bean，不会对其执行自动装配，也不会进行任何@Value处理.后者对于BeanFactoryPostProcessor也是适用的.Class type you've specified and instantiates it to use its matches method. It doesn't consider the instance as a bean, it doesn't perform autowiring on it, nor any @Value processing. The latter are true for BeanFactoryPostProcessor as well.ConditionContext中检索Environment.另一种方法是自己加载属性.Environment from the ConditionContext if you want to. The alternative is to load the properties yourself.
