jersey jax-rs Web服务中的init方法 [英] init method in jersey jax-rs web service

问题描述

我是jax-rs的新手，并且已经用球衣和glassfish构建了Web服务.

I'm new with jax-rs and have build a web service with jersey and glassfish.

我需要的是一种方法，服务启动后即被调用.在这种方法中，我想加载自定义配置文件，设置一些属性，编写日志等等...

What I need is a method, which is called once the service is started. In this method I want to load a custom config file, set some properties, write a log, and so on ...

我尝试使用servlet的构造函数，但是每次调用GET或POST方法时都会调用该构造函数.

I tried to use the constructor of the servlet but the constructor is called every time a GET or POST method is called.

我必须意识到哪些选择?

what options I have to realize that?

请告诉我们，如果需要一些依赖项，请给我一个想法，如何将其添加到pom.xml中(否则)

Please tell, if some dependencies are needed, give me an idea how to add it to the pom.xml (or else)

推荐答案

有多种方法可以实现它，具体取决于应用程序中可用的内容:

There are multiple ways to achieve it, depending on what you have available in your application:

一旦JAX-RS建立在Servlet API的顶部，下面的代码就可以解决问题:

Once JAX-RS is built on the top of the Servlet API, the following piece of code will do the trick:

@WebListener
public class StartupListener implements ServletContextListener {

    @Override
    public void contextInitialized(ServletContextEvent event) {
        // Perform action during application's startup
    }

    @Override
    public void contextDestroyed(ServletContextEvent event) {
        // Perform action during application's shutdown
    }
}

使用 @ApplicationScoped 和<来自CDI的a href ="http://docs.oracle.com/javaee/7/api/javax/enterprise/event/Observes.html" rel ="noreferrer"> @Observes

将JAX-RS与CDI结合使用时，您可以拥有以下内容:

Using @ApplicationScoped and @Observes from CDI

When using JAX-RS with CDI, you can have the following:

@ApplicationScoped
public class StartupListener {

    public void init(@Observes 
                     @Initialized(ApplicationScoped.class) ServletContext context) {
        // Perform action during application's startup
    }

    public void destroy(@Observes 
                        @Destroyed(ApplicationScoped.class) ServletContext context) {
        // Perform action during application's shutdown
    }
}

在这种方法中，您必须使用 @ApplicationScoped 从javax.enterprise.context包中获得，而不是 包中的rel ="noreferrer"> @ApplicationScoped .

In this approach, you must use @ApplicationScoped from the javax.enterprise.context package and not @ApplicationScoped from the javax.faces.bean package.

将JAX-RS与EJB一起使用时，您可以尝试:

When using JAX-RS with EJB, you can try:

@Startup
@Singleton
public class StartupListener {

    @PostConstruct
    public void init() {
        // Perform action during application's startup
    }

    @PreDestroy
    public void destroy() {
        // Perform action during application's shutdown
    }
}

---

如果您有兴趣阅读属性文件，请检查此问题.如果您使用的是CDI，并且愿意向您的项目添加 Apache DeltaSpike 依赖项，请考虑查看此 answer .

---

If you are interested in reading a properties file, check this question. If you are using CDI and you are open to add Apache DeltaSpike dependencies to your project, considering having a look at this answer.

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