springboot注册servlet
有时候在springboot中依然需要注册servlet，filter，listener，就以servlet为例来进行说明，另外两个也都类似
使用@WebServlet注解
在servlet3.0之后，servlet注册支持注解注册，而不需要在web.xml中进行配置，类似的，对于Filter使用@WebFilter注解，对于Listener使用@WebListener注解
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| @WebServlet(name = "helloWorldServlet",urlPatterns = "/helloWorldServlet",
initParams = {
@WebInitParam(name = "name",value = "张三")
})
public class HelloWorldServlet extends HttpServlet {
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
String name = getServletConfig().getInitParameter("name");
System.out.println("helloWorldServlet ---- doPost");
resp.getOutputStream().println(name);
}
}
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使用ServletRegistrationBean
springboot为注册servlet专门提供了一个bean，可以使用该bean进行注册，类似的对于Filter提供了FilterRegistrationBean，对于Listener提供了ServletListenerRegistrationBean
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| @Configuration
public class ServletRegistConfig {
@Bean
public ServletRegistrationBean registServlet(){
ServletRegistrationBean servletRegistrationBean = new ServletRegistrationBean();
servletRegistrationBean.setServlet(new RegistServlet());
List<String> urlMappings = new ArrayList<>();
urlMappings.add("/registServlet");
servletRegistrationBean.setUrlMappings(urlMappings);
servletRegistrationBean.setName("registServlet");
Map<String,String> initMap = new HashMap<>();
initMap.put("name","李四");
servletRegistrationBean.setInitParameters(initMap);
return servletRegistrationBean;
}
}
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动态注册
springboot中还提供了动态注册的方式，需要实现ServletContextInitializer接口
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| @Component
public class ServletRegistConfiguration implements ServletContextInitializer {
@Override
public void onStartup(ServletContext servletContext) throws ServletException {
ServletRegistration.Dynamic dynamic = servletContext.addServlet("registServlet", RegistServlet.class);
dynamic.addMapping("/regist");
dynamic.setInitParameter("name","王五");
}
}
|