Guice log4j 自定义注入不支持在构造函数内进行日志记录

发布于 2024-11-18 17:03:43 字数 702 浏览 1 评论 0原文

我正在尝试使用 Guice 将 Log4J Logger 实例注入类中，如 Guice 文档中所述：

http://code.google.com/p/google-guice/wiki/CustomInjections

但是，正如该 wiki 页面上的一些评论所述，此方案不支持构造函数注入。所以我不能这样做：

public class Foo {
    @InjectLogger Logger logger;

    @Inject
    public Foo(<injected parameters>) {
        logger.info("this won't work because logger hasn't been injected yet");
        ...
    }

    public bar() {
        logger.info("this will work because by the time bar() is called,")
        logger.info("the logger has been injected");
    }
}

是否有另一种方法来处理此注入，以便及时注入记录器供构造函数使用？

原文

I'm trying to use Guice to inject Log4J Logger instances into classes as described in the Guice documentation:

http://code.google.com/p/google-guice/wiki/CustomInjections

However, as noted in some of the comments on that wiki page, this scheme does not support a constructor injection. So I can't do this:

public class Foo {
    @InjectLogger Logger logger;

    @Inject
    public Foo(<injected parameters>) {
        logger.info("this won't work because logger hasn't been injected yet");
        ...
    }

    public bar() {
        logger.info("this will work because by the time bar() is called,")
        logger.info("the logger has been injected");
    }
}

Is there another way to handle this injection so that the logger is injected in time for the constructor to use?

分享到QQ

分享到微博

如果你对这篇内容有疑问，欢迎到本站社区发帖提问参与讨论，获取更多帮助，或者扫码二维码加入 Web 技术交流群。

发布评论

需要登录才能够评论，你可以免费注册一个本站的账号。

微凉徒眸意 2024-11-25 17:03:43

感谢 jfpoilpret 的帮助，我能够得到我想要的行为。当 Logger 变量修改为静态时，我在hear() 中使用了条件来利用反射，否则它使用正常的 Guice 字段注入。

public <T> void hear(TypeLiteral<T> typeLiteral, TypeEncounter<T> typeEncounter) {  
    for (Field field : typeLiteral.getRawType().getDeclaredFields()) {
        if (field.getType() == Logger.class && field.isAnnotationPresent(InjectLogger.class)) {
            if (Modifier.isStatic(field.getModifiers())) {
                // use reflection
                try {
                    field.setAccessible(true);
                    Logger logger = Logger.getLogger(field.getDeclaringClass());
                    field.set(null, logger);
                } catch (IllegalAccessException iae) { }
            } else {
                // register a member injector 
                Log4JMembersInjector<T> memberInjector = new Log4JMembersInjector<T>(field);
                typeEncounter.register(memberInjector);
            }
        }
    }
}

Thanks to the help from jfpoilpret, I was able to get the behavior I wanted. I used a conditional in hear() to leverage reflection when the Logger variable is modified as static, otherwise it uses normal Guice field injection.

public <T> void hear(TypeLiteral<T> typeLiteral, TypeEncounter<T> typeEncounter) {  
    for (Field field : typeLiteral.getRawType().getDeclaredFields()) {
        if (field.getType() == Logger.class && field.isAnnotationPresent(InjectLogger.class)) {
            if (Modifier.isStatic(field.getModifiers())) {
                // use reflection
                try {
                    field.setAccessible(true);
                    Logger logger = Logger.getLogger(field.getDeclaringClass());
                    field.set(null, logger);
                } catch (IllegalAccessException iae) { }
            } else {
                // register a member injector 
                Log4JMembersInjector<T> memberInjector = new Log4JMembersInjector<T>(field);
                typeEncounter.register(memberInjector);
            }
        }
    }
}

回复收藏 0 原文

~没有更多了~