java - @Value注解不起作用

Question

我正在使用 spring 应用程序，我尝试使用 @Value 注释从属性文件加载属性，但变量始终为 null。

这是我使用带注释变量的代码:

@Service
public class RulesEngineServiceImpl implements IRulesEngineService {
 @Value("${display.property}") static String displayProperty;
 @Value("${return.enabled}") static boolean returnEnabled;
 @Value("${return.type}") static String returnType;
 @Value("${immediaterpi}") static boolean immediaterpi;

 private static Rule getDefaultRule() {
    LOG.info("applying default rule displayProperty ="+displayProperty+"|  returnEnabled="+returnEnabled+"| returnType="+returnType+" | immediaterpi="+immediaterpi);
    Rule rule = new Rule();
    rule.setName("DEFAULT_RULE");
    rule.setDisplayProperty(DisplayProperty.valueOf(displayProperty));
    ActionProperty actionProperty = new ActionProperty();
    ReturnActionVO returnAction = new ReturnActionVO(returnEnabled, returnType, immediaterpi);
    actionProperty.setActions(JSONUtils.writeJson(returnAction));
    rule.setActionProperty(actionProperty);
    return rule;
 }
}

这是名为 application.prop 的属性文件，其中定义了这些属性:

display.property=xzc
return.enabled=false
return.type=""
immediaterpi=false

我在此处提供了对此文件的引用:

@PropertySources({
    @PropertySource("classpath:application.prop")})
public class PieApplication extends SpringBootServletInitializer 
{

 @Bean
 public PieServletContextListener pieServletContextListener() {
    return new PieServletContextListener();
 } 

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

}

但是当我从其他代码中调用该方法getDefaultRule()时，它不会加载像displayProperty这样的变量并打印日志如下:

applying default rule displayProperty =null|  returnEnabled=false| returnType=null | immediaterpi=false

请多多指教。

编辑:下面是代码更改，以防我将它们设为非静态

@Value("${display.property}")  String displayProperty;
@Value("${return.enabled}") boolean returnEnabled;
@Value("${return.type}")  String returnType;
@Value("${immediaterpi}")  boolean immediaterpi;

private static Rule getDefaultRule() {
    RulesEngineServiceImpl rulesEngineService = new RulesEngineServiceImpl();

    LOG.info("applying default rule displayProperty ="+rulesEngineService.displayProperty+"|  returnEnabled="+rulesEngineService.returnEnabled+"| returnType="+rulesEngineService.returnType+" | immediaterpi="+rulesEngineService.immediaterpi);
    Rule rule = new Rule();
    rule.setName("DEFAULT_RULE");
    rule.setDisplayProperty(DisplayProperty.valueOf(rulesEngineService.displayProperty));
    ActionProperty actionProperty = new ActionProperty();
    ReturnActionVO returnAction = new ReturnActionVO(rulesEngineService.returnEnabled, rulesEngineService.returnType, rulesEngineService.immediaterpi);
    actionProperty.setActions(JSONUtils.writeJson(returnAction));
    rule.setActionProperty(actionProperty);
    return rule;
}

但是结果还是一样。我的问题是该字段何时被初始化？应该如何从静态方法访问它，因为访问它的方法不能成为非静态的？

Answer 1

您不能在静态字段上使用@Value。使字段非静态。