Question

我有一个Spring Boot，我已经自动配置了一个Router bean。这一切都很完美，但当我想将bean注入自定义servlet时，它就成了一个问题：

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();
    }
}

这应该是要走的路，但是

SpringBeanAutowiringSupport.processInjectionBasedOnCurrentContext(this);

不会自动装配路由器，因为WebapplicationContext始终为空。该应用程序在MVC环境中运行。

Answer 1

假设您将Spring Application Context连接到Servlet Context，您可能希望将ServletContext传递给https://www.typescriptlang.org/

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

如何将'Router'作为构造函数参数注入。

所以你会有这个：

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();
    }
}

然后您可以以编程方式创建这样的servlet注册：

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

Answer 3

嵌入式服务器

您可以使用@WebServlet servlet类进行注释：

@WebServlet(urlPatterns = "/example")
public class ExampleServlet extends HttpServlet

在基类上启用@ServletComponentScan：

@ServletComponentScan
@EntityScan(basePackageClasses = { ExampleApp.class, Jsr310JpaConverters.class })
@SpringBootApplication
public class ExampleApp

但注入@ServletComponentScan仅适用于嵌入式服务器：

启用对Servlet组件的扫描（过滤器，servlet和听众）。仅在使用嵌入式Web时执行扫描服务器

更多信息：The @ServletComponentScan Annotation in Spring Boot

外部服务器

使用外部服务器时，将HttpServlet类标记为@Component：

@Component
public class ExampleServlet extends HttpServlet

创建配置类：

@Configuration
@ComponentScan(value = "com.example.servlet.package")
public class ServletConfig {

    @Autowired
    private ExampleServlet exampleServlet;

    @Bean
    public ServletRegistrationBean resetServletRegistrationBean(){
        return new ServletRegistrationBean(exampleServlet, "/example");
    }
}

Spring Boot：将Bean注入HttpServlet

3 个答案: