Spring Boot：將Bean注入到HttpServlet中

Question

我有一個Spring Boot，我已經自動配置了一個Router Bean。 這一切都可以完美運行，但是當我想對這個bean注入到一個特定的Servlet它成爲一個問題：

public class MembraneServlet extends HttpServlet { 
    @Autowired 
    private Router router; 

    @Override 
    public void init() throws ServletException { 
     SpringBeanAutowiringSupport.processInjectionBasedOnCurrentContext(this); 
    } 

    @Override 
    protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { 
     new HttpServletHandler(req, resp, router.getTransport()).run(); 
    } 
} 

這應該是要走的路，但

SpringBeanAutowiringSupport.processInjectionBasedOnCurrentContext(this); 

不會自動裝配的因爲WebapplicationContext始終爲空。該應用程序在MVC環境中運行。

Answer 1

假設你的Spring應用上下文被連接到servlet上下文，你可能想將ServletContext傳遞給SpringBeanAutowiringSupport.processInjectionBasedOnCurrentContext

public class MembraneServlet extends HttpServlet { 

    @Autowired 
    private Router router; 

    @Override 
    public void init() throws ServletException { 
     SpringBeanAutowiringSupport.processInjectionBasedOnCurrentContext(this, getServletContext()); 
    } 

    @Override 
    protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { 
     new HttpServletHandler(req, resp, router.getTransport()).run(); 
    } 
} 

Answer 2

注入'Router'作爲構造參數怎麼樣？

所以你要有這樣的：

public class MembraneServlet extends HttpServlet { 

    private Router router; 

    public MembraneServlet(Router router){ 
     this.router = router; 
    } 

    @Override 
    public void init() throws ServletException { 
     SpringBeanAutowiringSupport.processInjectionBasedOnCurrentContext(this); 
    } 

    @Override 
    protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { 
     new HttpServletHandler(req, resp, router.getTransport()).run(); 
    } 
} 

則可以編程方式創建的servlet註冊是這樣的：

@Bean 
public ServletRegistrationBean membraneServletRegistrationBean(){ 
    return new ServletRegistrationBean(new MembraneServlet(),"/*"); 
}