JAVA-86: spring-boot-add-filter

spring-boot-modules/spring-boot-basic-customization/README.md

@@ -9,3 +9,4 @@ This module contains articles about Spring Boot customization
  - [Create a Custom FailureAnalyzer with Spring Boot](https://www.baeldung.com/spring-boot-failure-analyzer)
  - [Spring Boot: Customize Whitelabel Error Page](https://www.baeldung.com/spring-boot-custom-error-page)
  - [Spring Boot: Configuring a Main Class](https://www.baeldung.com/spring-boot-main-class)
+ - [How to Define a Spring Boot Filter?](https://www.baeldung.com/spring-boot-add-filter)

spring-boot-modules/spring-boot-basic-customization/src/main/java/com/baeldung/bootcustomfilters/FilterConfig.java

@@ -0,0 +1,23 @@
+package com.baeldung.bootcustomfilters;
+
+import com.baeldung.bootcustomfilters.filters.RequestResponseLoggingFilter;
+import org.springframework.boot.web.servlet.FilterRegistrationBean;
+import org.springframework.context.annotation.Configuration;
+
+@Configuration
+public class FilterConfig {
+
+    // uncomment this and comment the @Component in the filter class definition to register only for a url pattern
+    // @Bean
+    public FilterRegistrationBean<RequestResponseLoggingFilter> loggingFilter() {
+        FilterRegistrationBean<RequestResponseLoggingFilter> registrationBean = new FilterRegistrationBean<>();
+
+        registrationBean.setFilter(new RequestResponseLoggingFilter());
+
+        registrationBean.addUrlPatterns("/users/*");
+
+        return registrationBean;
+
+    }
+
+}

spring-boot-modules/spring-boot-basic-customization/src/main/java/com/baeldung/bootcustomfilters/SpringBootFiltersApplication.java

@@ -0,0 +1,17 @@
+package com.baeldung.bootcustomfilters;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+/**
+ * Boot application
+ * @author hemant
+ *
+ */
+@SpringBootApplication
+public class SpringBootFiltersApplication {
+
+	public static void main(String[] args) {
+		SpringApplication.run(SpringBootFiltersApplication.class, args);
+	}
+}

spring-boot-modules/spring-boot-basic-customization/src/main/java/com/baeldung/bootcustomfilters/controller/UserController.java

@@ -0,0 +1,34 @@
+package com.baeldung.bootcustomfilters.controller;
+
+import com.baeldung.bootcustomfilters.model.User;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.UUID;
+
+/**
+ * Rest controller for User
+ * @author hemant
+ *
+ */
+@RestController
+@RequestMapping("/users")
+public class UserController {
+
+	private static final Logger LOG = LoggerFactory.getLogger(UserController.class);
+
+	@GetMapping("")
+	public List<User> getAllUsers() {
+		LOG.info("Fetching all the users");
+		return Arrays.asList(
+				new User(UUID.randomUUID().toString(), "User1", "user1@test.com"),
+				new User(UUID.randomUUID().toString(), "User1", "user1@test.com"),
+				new User(UUID.randomUUID().toString(), "User1", "user1@test.com"));
+	}
+
+}

spring-boot-modules/spring-boot-basic-customization/src/main/java/com/baeldung/bootcustomfilters/filters/RequestResponseLoggingFilter.java

@@ -0,0 +1,44 @@
+package com.baeldung.bootcustomfilters.filters;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.core.annotation.Order;
+import org.springframework.stereotype.Component;
+
+import javax.servlet.*;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import java.io.IOException;
+
+/**
+ * A servlet filter to log request and response
+ * The logging implementation is pretty native and for demonstration only
+ * @author hemant
+ *
+ */
+@Component
+@Order(2)
+public class RequestResponseLoggingFilter implements Filter {
+
+	private final static Logger LOG = LoggerFactory.getLogger(RequestResponseLoggingFilter.class);
+
+	@Override
+	public void init(final FilterConfig filterConfig) throws ServletException {
+		LOG.info("Initializing filter :{}", this);
+	}
+
+	@Override
+	public void doFilter(final ServletRequest request, final ServletResponse response, final FilterChain chain)
+			throws IOException, ServletException {
+		HttpServletRequest req = (HttpServletRequest) request;
+		HttpServletResponse res = (HttpServletResponse) response;
+		LOG.info("Logging Request  {} : {}", req.getMethod(), req.getRequestURI());
+		chain.doFilter(request, response);
+		LOG.info("Logging Response :{}", res.getContentType());
+	}
+
+	@Override
+	public void destroy() {
+		LOG.warn("Destructing filter :{}", this);
+	}
+}

spring-boot-modules/spring-boot-basic-customization/src/main/java/com/baeldung/bootcustomfilters/filters/TransactionFilter.java

@@ -0,0 +1,41 @@
+package com.baeldung.bootcustomfilters.filters;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.core.annotation.Order;
+import org.springframework.stereotype.Component;
+
+import javax.servlet.*;
+import javax.servlet.http.HttpServletRequest;
+import java.io.IOException;
+
+/**
+ * A filter to create transaction before and commit it once request completes
+ * The current implemenatation is just for demo
+ * @author hemant
+ *
+ */
+@Component
+@Order(1)
+public class TransactionFilter implements Filter {
+
+	private final static Logger LOG = LoggerFactory.getLogger(TransactionFilter.class);
+
+	@Override
+	public void init(final FilterConfig filterConfig) throws ServletException {
+		LOG.info("Initializing filter :{}", this);
+	}
+
+	@Override
+	public void doFilter(final ServletRequest request, final ServletResponse response, final FilterChain chain) throws IOException, ServletException {
+		HttpServletRequest req = (HttpServletRequest) request;
+		LOG.info("Starting Transaction for req :{}", req.getRequestURI());
+		chain.doFilter(request, response);
+		LOG.info("Committing Transaction for req :{}", req.getRequestURI());
+	}
+
+	@Override
+	public void destroy() {
+		LOG.warn("Destructing filter :{}", this);
+	}
+}

spring-boot-modules/spring-boot-basic-customization/src/main/java/com/baeldung/bootcustomfilters/model/User.java

@@ -0,0 +1,45 @@
+package com.baeldung.bootcustomfilters.model;
+
+/**
+ * User model
+ * @author hemant
+ *
+ */
+public class User {
+
+	private String id;
+	private String name;
+	private String email;
+
+	public User(String id, String name, String email) {
+		super();
+		this.id = id;
+		this.name = name;
+		this.email = email;
+	}
+
+	public String getId() {
+		return id;
+	}
+
+	public void setId(String id) {
+		this.id = id;
+	}
+
+	public String getName() {
+		return name;
+	}
+
+	public void setName(String name) {
+		this.name = name;
+	}
+
+	public String getEmail() {
+		return email;
+	}
+
+	public void setEmail(String email) {
+		this.email = email;
+	}
+
+}