filter hierarchy

spring-security-rest-basic-auth/src/main/java/org/baeldung/security/filter/CustomHttpFilter.java

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+package org.baeldung.security.filter;
+
+import org.springframework.core.Ordered;
+import org.springframework.core.annotation.Order;
+import org.springframework.stereotype.Component;
+
+import javax.servlet.FilterChain;
+import javax.servlet.FilterConfig;
+import javax.servlet.ServletException;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import java.io.IOException;
+
+@Component
+@Order(Ordered.LOWEST_PRECEDENCE)
+public class CustomHttpFilter extends GenericCustomHttpFilter {
+
+    @Override
+    public void init(FilterConfig config) throws ServletException {
+        System.out.println(config.getInitParameter("first-init-param") +
+                config.getInitParameter("second-init-param"));
+    }
+
+    @Override
+    public void doFilter(HttpServletRequest request, HttpServletResponse response, FilterChain
+            chain) throws IOException, ServletException {
+        System.out.println("CustomHttpFilter is in action [the request is going to the server].");
+        chain.doFilter(request, response);
+        System.out.println("CustomHttpFilter is in action [the request has come from the server].");
+    }
+
+}

spring-security-rest-basic-auth/src/main/java/org/baeldung/security/filter/FilterConfiguration.java

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+package org.baeldung.security.filter;
+
+import org.springframework.boot.context.embedded.FilterRegistrationBean;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+import java.util.HashMap;
+
+import static java.util.Collections.singletonList;
+
+@Configuration
+public class FilterConfiguration {
+
+    @Bean
+    public FilterRegistrationBean getCustomFilterRegistrationBean() {
+        FilterRegistrationBean registration = new FilterRegistrationBean();
+        registration.setFilter(new CustomHttpFilter());
+
+        registration.setInitParameters(new HashMap<String, String>() {{
+            put("first-init-param", "Hello from ");
+            put("second-init-param", "Filter!");
+        }});
+        registration.setUrlPatterns(singletonList("/user/registration"));
+
+        return registration;
+    }
+
+}

spring-security-rest-basic-auth/src/main/java/org/baeldung/security/filter/GenericCustomFilter.java

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+package org.baeldung.security.filter;
+
+
+import javax.servlet.Filter;
+import javax.servlet.FilterConfig;
+import javax.servlet.ServletException;
+
+public abstract class GenericCustomFilter implements Filter {
+
+    @Override
+    public void init(FilterConfig filterConfig) throws ServletException {}
+
+    @Override
+    public void destroy() {}
+
+}

spring-security-rest-basic-auth/src/main/java/org/baeldung/security/filter/GenericCustomHttpFilter.java

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+package org.baeldung.security.filter;
+
+import javax.servlet.FilterChain;
+import javax.servlet.ServletException;
+import javax.servlet.ServletRequest;
+import javax.servlet.ServletResponse;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import java.io.IOException;
+
+public abstract class GenericCustomHttpFilter extends GenericCustomFilter {
+
+    @Override
+    public void doFilter(ServletRequest request, ServletResponse response,
+                         FilterChain chain) throws IOException, ServletException {
+        doFilter((HttpServletRequest) request, (HttpServletResponse) response, chain);
+    }
+
+    public abstract void doFilter(HttpServletRequest request, HttpServletResponse response,
+                                  FilterChain chain) throws IOException, ServletException;
+
+}