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Spring Boot基础教程10-web应用开发-Servlets, Filters, listeners
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Web开发使用 Controller 基本上可以完成大部分需求,但是我们还可能会用到 Servlet、 Filter、Listener等等
 
二.在spring boot中的三种实现方式
  方法一:通过注册ServletRegistrationBean、 FilterRegistrationBean 和 ServletListenerRegistrationBean 获得控制
 
/**
 * 自定义servlet
 *
 * @author wujing
 */
public class CustomServlet extends HttpServlet {
 
  /**
   *
   */
  private static final long serialVersionUID = 1L;
 
  @Override
  protected void doGet(HttpServletRequest request, HttpServletResponse response)
         throws ServletException, IOException {
    System.out.println("servlet get method");
    doPost(request, response);
  }
 
  @Override
  protected void doPost(HttpServletRequest request, HttpServletResponse response)
         throws ServletException, IOException {
    System.out.println("servlet post method");
    response.getWriter().write("hello world");
  }
 
}
 
/**
 * 自定义filter
 *
 * @author wujing
 */
public class CustomFilter implements Filter {
 
  @Override
  public void init(FilterConfig filterConfig) throws ServletException {
    System.out.println("init filter");
  }
 
  @Override
  public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
         throws IOException, ServletException {
    System.out.println("do filter");
    chain.doFilter(request, response);
  }
 
  @Override
  public void destroy() {
    System.out.println("destroy filter");
  }
 
}
 
/**
 * 自定义listener
 *
 * @author wujing
 */
public class CustomListener implements ServletContextListener {
 
  @Override
  public void contextInitialized(ServletContextEvent sce) {
    System.out.println("contextInitialized");
  }
 
  @Override
  public void contextDestroyed(ServletContextEvent sce) {
    System.out.println("contextDestroyed");
  }
 
}
 
注册bean
 
@Bean
  public ServletRegistrationBean servletRegistrationBean() {
    return new ServletRegistrationBean(new CustomServlet(), "/roncoo");
  }
 
  @Bean
  public FilterRegistrationBean filterRegistrationBean() {
    return new FilterRegistrationBean(new CustomFilter(), servletRegistrationBean());
  }
 
  @Bean
  public ServletListenerRegistrationBean<CustomListener> servletListenerRegistrationBean() {
    return new ServletListenerRegistrationBean<CustomListener>(new CustomListener());
  }
 
  方法二:通过实现 ServletContextInitializer 接口直接注册
 
implements ServletContextInitializer {
 
   @Override
   public void onStartup(ServletContext servletContext) throws ServletException {
      servletContext.addServlet("customServlet", new CustomServlet()).addMapping("/roncoo");
      servletContext.addFilter("customFilter", new CustomFilter())
            .addMappingForServletNames(EnumSet.of(DispatcherType.REQUEST), true, "customServlet");
      servletContext.addListener(new CustomListener());
  }
 
  方法三:在 SpringBootApplication 上使用@ServletComponentScan 注解后,直接通过@WebServlet、@WebFilter、@WebListener 注解自动注册
 

更多参考内容:http://www.roncoo.com/article/index

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芝麻绿豆
发帖于9个月前 0回/126阅
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