dependency-injection - 如何用 Dagger 初始化网络应用程序？

Question

我需要向 contextInitialized 方法添加什么才能正确初始化对象图？

给定这个 Dagger 模块:

@Module
public class MapperModule {

    @Provides
    @Singleton
    ObjectMapper provideObjectMapper() {
        return new ObjectMapper();
    }

}

ServletContextListener 的这个子类:

public class DaggerDi implements ServletContextListener {

    @Override
    public void contextInitialized(ServletContextEvent sce) {
        ObjectGraph objectGraph = ObjectGraph.create(new MapperModule());                
     }

    @Override
    public void contextDestroyed(ServletContextEvent sce) {

    }

}

和 web.xml

<web-app>
  <display-name>Archetype Created Web Application</display-name>
   <listener>
    <listener-class>
             com.me.config.DaggerDi
        </listener-class>
   </listener>
</web-app>

Answer 1

可以查看this dagger-servlet project ，我还没有尝试过，但看起来很简单，你将不得不:

1. 配置 servlet(web.xml 文件):

<web-app>
    <listener>
        <listener-class>com.example.MyServletContextListener</listener-class>
    </listener>
    <filter>
        <filter-name>Dagger Filter</filter-name>
        <filter-class>com.leacox.dagger.servlet.DaggerFilter</filter-class>
    </filter>
    <filter-mapping>
        <filter-name>Dagger Filter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>
</web-app>

1. 实现上下文监听器和模块:

   @Module(注入(inject) = {...}，包括 = ServletModule.class) 公共(public)类 MyModule {}

   @Module(注入(inject) = {...}，包括 = ServletRequestModule.class) 公共(public)类 MyRequestModule {}

   公共(public)类 MyServletContextListener 扩展 DaggerServletContextListener { @覆盖 protected 类 [] getBaseModules() { 返回新类[]{MyModule.class}；

   @Override
   protected Class<?>[] getRequestScopedModules() {
       return new Class<?>[]{MyRequestModule.class};
   }
   

问候!