java - 如何在spring类的方法中访问属性文件值

Question

我正在使用 spring 4.0.3.RELEASE

这是我的applicationContext.xml，我在其中配置PropertyPlaceHolder

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:p="http://www.springframework.org/schema/p"
       xmlns:util="http://www.springframework.org/schema/util"
       xmlns:tx="http://www.springframework.org/schema/tx"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
          http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd
          http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-4.0.xsd
          http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.0.xsd
          http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.0.xsd

       http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.0.xsd">
    <mvc:annotation-driven/>
    <context:component-scan base-package="org.graphsearch.tutor.service.impls, org.graphsearch.tutor.dao.impls, org.graphsearch.tutor.configs, org.graphsearch.tutor.utils"/>
    <bean id="propertyConfigurer" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
        <property name="locations">
            <list>
                <value>/WEB-INF/properties/database/jdbc.properties</value>
                <value>/WEB-INF/properties/alert/message.properties</value>
                <value>/WEB-INF/properties/email/mail.properties</value>
                <value>/WEB-INF/properties/logger/logging.properties</value>
            </list>
        </property>
    </bean>
</beans>

在电子邮件客户端类中，我正在注入(inject)这样的属性值

@Component
public class EmailClient {

    @Value("${tutor.mail.common.note}")
    private static String NOTE;

    @Value("${tutor.mail.common.regards}")
    private static String REGARDS;

    @Value("${tutor.mail.from}")
    private static String FROM;

    @Autowired
    private MailSender mailSender;

    @Autowired
    private Environment env;

    public void sendRegisterMail(User user){
        SimpleMailMessage message = new SimpleMailMessage();
        message.setTo(user.getEmailID());
        String subject = env.getProperty("tutor.register.success.mail.subject"); //retuns null
        String contentTemplate = env.getProperty("tutor.register.success.mail.content"); //returns null
        MessageFormat format = new MessageFormat(contentTemplate);
        Object[] args = {user.getFullName()};
        StringBuffer content = new StringBuffer();
        content.append(format.format(args));
        content.append(NOTE);
        content.append(REGARDS);
        message.setSubject(subject);
        message.setText(content.toString());
        mailSender.send(message);
    }
}

现在的问题是 @Value("${property.key}") 在我注入(inject)类的私有(private)字段(如 NOTE、REGARDS、FROM)时确实像魅力一样工作。

但是如果我在方法 sendRegisterMail() 中需要这个值@Value("$key") 给出了编译器错误。我在 web 上搜索了几个示例，这些示例是通过环境获取属性值的，所以我像在 EmailClient 类中所做的那样使用，但它总是给我 null。我检查了日志，它说找不到属性 key 。

有人能告诉我如何在方法中注入(inject)属性值吗？提前致谢

Answer 1

尝试

@Value("#{propertyConfigurer['tutor.mail.common.note']}")
private static String NOTE;

有关更多信息，请查看 How can I inject a property value into a Spring Bean which was configured using annotations?