Spring Boot filter WebFilter annotation example 2019-06-16 11:51
There is an embedded tomcat in Spring Boot. We can not edit web.xml to add a filter. In this page I will show you how to add filter in Spring Boot without web.xml. I use WebFilter annotation to add filter. After adding this annotation you have to add ServletComponentScan annotation to make Spring Boot find this filter.
Here is the complete code.
@SpringBootApplication
@EnableAutoConfiguration
@EnableWebMvc
@ServletComponentScan(basePackages = "com.henryxi.filter")
public class Application {
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
}
@WebFilter(filterName = "myFilter",urlPatterns = "/filter")
public class MyFilter implements Filter {
public void init(FilterConfig filterConfig) throws ServletException {
}
public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
PrintWriter writer = servletResponse.getWriter();
writer.print("this is filter");
servletResponse.setContentType("text/html;charset=UTF-8");
}
public void destroy() {
}
}
@Controller
public class MyController {
@ResponseBody
@RequestMapping("/**")
public String anyRequest(){
return "this is available page.";
}
}
Request localhost:8080/filter you will get the message "this is filter".
Request any other path you will get the message "this is available page.".
Note that the WebFilter annotation is not a spring annotation. It is in javax.servlet.annotation package. If you don't use embed tomcat you can also use this annotation to add filter. Servlet container handles this annotation. Adding this annotation has the same effect as declaring a filter in the web.xml file.
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