BAEL-5649 (#12677)

* add hexagonal architecture example project

* rename class

* add unit test and integration test

* add new line

* reorder pom

* remove maven wrapper

* [BAEL-5649] add article code

* remove files added by mistake

* get parameter type using reflection and serioalize JSON into POJOs

* clean code

* clean code

* reformat

* implement PR feedback

* reformat with contiunation space eq to 2

* replace UserDto with firstName and lastName

spring-web-modules/spring-mvc-basics-5/pom.xml

@@ -38,6 +38,17 @@
             <artifactId>spring-boot-starter-test</artifactId>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-io</artifactId>
+            <version>1.3.2</version>
+        </dependency>
+        <dependency>
+            <groupId>com.jayway.jsonpath</groupId>
+            <artifactId>json-path</artifactId>
+            <version>2.7.0</version>
+        </dependency>
+
     </dependencies>
 
     <build>

spring-web-modules/spring-mvc-basics-5/src/main/java/com/baeldung/jsonargs/AddressDto.java

@@ -0,0 +1,55 @@
+package com.baeldung.jsonargs;
+
+public class AddressDto {
+
+    private String streetName;
+    private String streetNumber;
+    private String postalCode;
+    private String city;
+    private String country;
+
+    public String getStreetName() {
+        return streetName;
+    }
+
+    public void setStreetName(String streetName) {
+        this.streetName = streetName;
+    }
+
+    public String getStreetNumber() {
+        return streetNumber;
+    }
+
+    public void setStreetNumber(String streetNumber) {
+        this.streetNumber = streetNumber;
+    }
+
+    public String getPostalCode() {
+        return postalCode;
+    }
+
+    public void setPostalCode(String postalCode) {
+        this.postalCode = postalCode;
+    }
+
+    public String getCity() {
+        return city;
+    }
+
+    public void setCity(String city) {
+        this.city = city;
+    }
+
+    public String getCountry() {
+        return country;
+    }
+
+    public void setCountry(String country) {
+        this.country = country;
+    }
+
+    @Override
+    public String toString() {
+        return "Address{" + "streetName='" + streetName + '\'' + ", streetNumber='" + streetNumber + '\'' + ", postalCode='" + postalCode + '\'' + ", city='" + city + '\'' + ", country='" + country + '\'' + '}';
+    }
+}

spring-web-modules/spring-mvc-basics-5/src/main/java/com/baeldung/jsonargs/JsonArg.java

@@ -0,0 +1,12 @@
+package com.baeldung.jsonargs;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+@Target(ElementType.PARAMETER)
+@Retention(RetentionPolicy.RUNTIME)
+public @interface JsonArg {
+    String value() default "";
+}

spring-web-modules/spring-mvc-basics-5/src/main/java/com/baeldung/jsonargs/JsonArgumentResolver.java

@@ -0,0 +1,50 @@
+package com.baeldung.jsonargs;
+
+import java.io.IOException;
+import java.util.Objects;
+
+import javax.servlet.http.HttpServletRequest;
+
+import org.apache.commons.io.IOUtils;
+import org.springframework.core.MethodParameter;
+import org.springframework.web.bind.support.WebDataBinderFactory;
+import org.springframework.web.context.request.NativeWebRequest;
+import org.springframework.web.method.support.HandlerMethodArgumentResolver;
+import org.springframework.web.method.support.ModelAndViewContainer;
+
+import com.jayway.jsonpath.JsonPath;
+
+public class JsonArgumentResolver implements HandlerMethodArgumentResolver {
+
+    private static final String JSON_BODY_ATTRIBUTE = "JSON_REQUEST_BODY";
+
+    @Override
+    public boolean supportsParameter(MethodParameter parameter) {
+        return parameter.hasParameterAnnotation(JsonArg.class);
+    }
+
+    @Override
+    public Object resolveArgument(MethodParameter parameter, ModelAndViewContainer mavContainer, NativeWebRequest webRequest, WebDataBinderFactory binderFactory) throws Exception {
+        String body = getRequestBody(webRequest);
+        String jsonPath = Objects.requireNonNull(Objects.requireNonNull(parameter.getParameterAnnotation(JsonArg.class))
+          .value());
+        Class<?> parameterType = parameter.getParameterType();
+        return JsonPath.parse(body)
+          .read(jsonPath, parameterType);
+    }
+
+    private String getRequestBody(NativeWebRequest webRequest) {
+        HttpServletRequest servletRequest = Objects.requireNonNull(webRequest.getNativeRequest(HttpServletRequest.class));
+        String jsonBody = (String) servletRequest.getAttribute(JSON_BODY_ATTRIBUTE);
+        if (jsonBody == null) {
+            try {
+                jsonBody = IOUtils.toString(servletRequest.getInputStream());
+                servletRequest.setAttribute(JSON_BODY_ATTRIBUTE, jsonBody);
+            } catch (IOException e) {
+                throw new RuntimeException(e);
+            }
+        }
+        return jsonBody;
+    }
+}
+

spring-web-modules/spring-mvc-basics-5/src/main/java/com/baeldung/jsonargs/UserController.java

@@ -0,0 +1,33 @@
+package com.baeldung.jsonargs;
+
+import org.springframework.http.ResponseEntity;
+import org.springframework.stereotype.Controller;
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.RequestBody;
+import org.springframework.web.bind.annotation.RequestMapping;
+
+@Controller
+@RequestMapping("/user")
+public class UserController {
+
+    @PostMapping("/process/custom")
+    public ResponseEntity process(@JsonArg("firstName") String firstName, @JsonArg("address.city") String city) {
+        /* business processing */
+        return ResponseEntity.ok()
+          .body(String.format("{\"firstName\": %s, \"city\" : %s}", firstName, city));
+    }
+
+    @PostMapping("/process")
+    public ResponseEntity process(@RequestBody UserDto user) {
+        /* business processing */
+        return ResponseEntity.ok()
+          .body(user.toString());
+    }
+
+    @PostMapping("/process/custompojo")
+    public ResponseEntity process(@JsonArg("firstName") String firstName, @JsonArg("lastName") String lastName, @JsonArg("address") AddressDto address) {
+        /* business processing */
+        return ResponseEntity.ok()
+          .body(String.format("{\"firstName\": %s, \"lastName\": %s, \"address\" : %s}", firstName, lastName, address));
+    }
+}

spring-web-modules/spring-mvc-basics-5/src/main/java/com/baeldung/jsonargs/UserDto.java

@@ -0,0 +1,46 @@
+package com.baeldung.jsonargs;
+
+public class UserDto {
+
+    private String firstName;
+    private String lastName;
+    private String age;
+    private AddressDto address;
+
+    public String getFirstName() {
+        return firstName;
+    }
+
+    public void setFirstName(String firstName) {
+        this.firstName = firstName;
+    }
+
+    public String getLastName() {
+        return lastName;
+    }
+
+    public void setLastName(String lastName) {
+        this.lastName = lastName;
+    }
+
+    public String getAge() {
+        return age;
+    }
+
+    public void setAge(String age) {
+        this.age = age;
+    }
+
+    public AddressDto getAddress() {
+        return address;
+    }
+
+    public void setAddress(AddressDto address) {
+        this.address = address;
+    }
+
+    @Override
+    public String toString() {
+        return "User{" + "firstName='" + firstName + '\'' + ", lastName='" + lastName + '\'' + ", age='" + age + '\'' + ", address=" + address + '}';
+    }
+}

spring-web-modules/spring-mvc-basics-5/src/main/java/com/baeldung/spring/web/config/WebConfig.java

@@ -1,7 +1,10 @@
 package com.baeldung.spring.web.config;
 
+import java.util.List;
+
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
+import org.springframework.web.method.support.HandlerMethodArgumentResolver;
 import org.springframework.web.servlet.ViewResolver;
 import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry;
 import org.springframework.web.servlet.config.annotation.ViewControllerRegistry;
@@ -11,18 +14,26 @@ import org.springframework.web.servlet.view.BeanNameViewResolver;
 import org.springframework.web.servlet.view.InternalResourceViewResolver;
 import org.springframework.web.servlet.view.JstlView;
 
+import com.baeldung.jsonargs.JsonArgumentResolver;
+
 @Configuration
 public class WebConfig implements WebMvcConfigurer {
 
     @Override
-    public void addViewControllers(final ViewControllerRegistry registry) {
+    public void addViewControllers(ViewControllerRegistry registry) {
         registry.addViewController("/")
           .setViewName("index");
     }
 
+    @Override
+    public void addArgumentResolvers(List<HandlerMethodArgumentResolver> argumentResolvers) {
+        JsonArgumentResolver jsonArgumentResolver = new JsonArgumentResolver();
+        argumentResolvers.add(jsonArgumentResolver);
+    }
+
     @Bean
     public ViewResolver viewResolver() {
-        final InternalResourceViewResolver bean = new InternalResourceViewResolver();
+        InternalResourceViewResolver bean = new InternalResourceViewResolver();
         bean.setViewClass(JstlView.class);
         bean.setPrefix("/WEB-INF/view/");
         bean.setSuffix(".jsp");
@@ -41,9 +52,10 @@ public class WebConfig implements WebMvcConfigurer {
     }
 
     @Bean
-    public BeanNameViewResolver beanNameViewResolver(){
+    public BeanNameViewResolver beanNameViewResolver() {
         BeanNameViewResolver beanNameViewResolver = new BeanNameViewResolver();
         beanNameViewResolver.setOrder(1);
         return beanNameViewResolver;
     }
+
 }

spring-web-modules/spring-mvc-basics-5/src/test/java/com/baeldung/jsonargs/UserControllerIntegrationTest.java

@@ -0,0 +1,52 @@
+package com.baeldung.jsonargs;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.post;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;
+
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.autoconfigure.web.servlet.WebMvcTest;
+import org.springframework.http.MediaType;
+import org.springframework.test.web.servlet.MockMvc;
+import org.springframework.test.web.servlet.result.MockMvcResultMatchers;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+
+@WebMvcTest(controllers = UserController.class)
+class UserControllerIntegrationTest {
+
+    @Autowired
+    private MockMvc mockMvc;
+
+    @Test
+    void whenSendingAPostJSON_thenReturnFirstNameAndCity() throws Exception {
+        String jsonString = "{\"firstName\":\"John\",\"lastName\":\"Smith\",\"age\":10,\"address\":{\"streetName\":\"Example Street\",\"streetNumber\":\"10A\",\"postalCode\":\"1QW34\",\"city\":\"Timisoara\",\"country\":\"Romania\"}}";
+        mockMvc.perform(post("/user/process/custom").content(jsonString)
+            .contentType(MediaType.APPLICATION_JSON)
+            .accept(MediaType.APPLICATION_JSON))
+          .andExpect(status().isOk())
+          .andExpect(MockMvcResultMatchers.jsonPath("$.firstName")
+            .value("John"))
+          .andExpect(MockMvcResultMatchers.jsonPath("$.city")
+            .value("Timisoara"));
+    }
+
+    @Test
+    void whenSendingAPostJSON_thenReturnUserAndAddress() throws Exception {
+        String jsonString = "{\"firstName\":\"John\",\"lastName\":\"Smith\",\"address\":{\"streetName\":\"Example Street\",\"streetNumber\":\"10A\",\"postalCode\":\"1QW34\",\"city\":\"Timisoara\",\"country\":\"Romania\"}}";
+        ObjectMapper mapper = new ObjectMapper();
+        UserDto user = mapper.readValue(jsonString, UserDto.class);
+        AddressDto address = user.getAddress();
+
+        String mvcResult = mockMvc.perform(post("/user/process/custompojo").content(jsonString)
+            .contentType(MediaType.APPLICATION_JSON)
+            .accept(MediaType.APPLICATION_JSON))
+          .andExpect(status().isOk())
+          .andReturn()
+          .getResponse()
+          .getContentAsString();
+
+        assertEquals(String.format("{\"firstName\": %s, \"lastName\": %s, \"address\" : %s}", user.getFirstName(), user.getLastName(), address), mvcResult);
+    }
+}