靜態代碼執行的時候，spring是沒有註入的，這個時候：

//錯誤的使用方法
@Value("${name}")
private static String name;

public static void test() {
    String s = name;
    System.out.println(s);
}

解決辦法：

@Component
public class Properties {

    @Value("${name}")
    private String name;
　　　　
    public getName(){
 
　　　　return name;
　　}

}

@Component
public class SpringContextUtil implements ApplicationContextAware {
    private static ApplicationContext applicationContext = null;

    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        if(SpringContextUtil.applicationContext == null){
            SpringContextUtil.applicationContext  = applicationContext;
        }
    }

    public static ApplicationContext getApplicationContext() {
        return applicationContext;
    }

    public static Object getBean(String name){
        return getApplicationContext().getBean(name);
    }

    public static <T> T getBean(Class<T> clazz){
        return getApplicationContext().getBean(clazz);
    }

    public static <T> T getBean(String name,Class<T> clazz){
        return getApplicationContext().getBean(name, clazz);
    }

public static void test() {
    Properties properties = SpringContextUtil.getBean(Properties.class);
    String s = properties.getName();
    System.out.println(s);//成功打印name值
}

使用springboot的同學，需要動態獲取生產、測試、開發環境的，可以在pom文件裏定義

<profile>
            <id>test</id>
            <properties>
                <profileActive>test</profileActive>
            </properties>
            <activation>
                <activeByDefault>true</activeByDefault><!--默認配置-->
            </activation>
        </profile>

<profile>
    <id>prod</id>
    <properties>
        <profileActive>prod</profileActive>
    </properties>
</profile>

在application.yml裏配置，系統根據pom定義的profileActive（test）會找相應的application-test.yml文件

spring:
  profiles:
    active: @[email protected]

Java靜態代碼獲取不到@value註入的值