BAEL-3324 | Using JSON Patch in Spring REST APIs

spring-rest-http/pom.xml

@@ -41,12 +41,18 @@
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-test</artifactId>
         </dependency>
+        <dependency>
+            <groupId>com.github.java-json-tools</groupId>
+            <artifactId>json-patch</artifactId>
+            <version>${jsonpatch.version}</version>
+        </dependency>
 
     </dependencies>
 
 
     <properties>
         <xstream.version>1.4.9</xstream.version>
+        <jsonpatch.version>1.12</jsonpatch.version>
     </properties>
 
 </project>

spring-rest-http/src/main/java/com/baeldung/CustomerSpringBootRestApplication.java

@@ -0,0 +1,12 @@
+package com.baeldung;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class CustomerSpringBootRestApplication {
+
+    public static void main(String[] args) {
+        SpringApplication.run(CustomerSpringBootRestApplication.class, args);
+    }
+}

spring-rest-http/src/main/java/com/baeldung/model/Customer.java

@@ -0,0 +1,79 @@
+package com.baeldung.model;
+
+import java.util.List;
+import java.util.Map;
+import java.util.Objects;
+
+public class Customer {
+    private String id;
+    private String telephone;
+    private List<String> favorites;
+    private Map<String, Boolean> communicationPreferences;
+
+    public Customer() {
+    }
+
+    public Customer(String id, String telephone, List<String> favorites, Map<String, Boolean> communicationPreferences) {
+        this(telephone, favorites, communicationPreferences);
+        this.id = id;
+    }
+
+    public Customer(String telephone, List<String> favorites, Map<String, Boolean> communicationPreferences) {
+        this.telephone = telephone;
+        this.favorites = favorites;
+        this.communicationPreferences = communicationPreferences;
+    }
+
+    public static Customer fromCustomer(Customer customer) {
+        return new Customer(customer.getId(), customer.getTelephone(), customer.getFavorites(), customer.getCommunicationPreferences());
+    }
+
+    public String getId() {
+        return id;
+    }
+
+    public void setId(String id) {
+        this.id = id;
+    }
+
+    public String getTelephone() {
+        return telephone;
+    }
+
+    public void setTelephone(String telephone) {
+        this.telephone = telephone;
+    }
+
+    public Map<String, Boolean> getCommunicationPreferences() {
+        return communicationPreferences;
+    }
+
+    public void setCommunicationPreferences(Map<String, Boolean> communicationPreferences) {
+        this.communicationPreferences = communicationPreferences;
+    }
+
+    public List<String> getFavorites() {
+        return favorites;
+    }
+
+    public void setFavorites(List<String> favorites) {
+        this.favorites = favorites;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) {
+            return true;
+        }
+        if (!(o instanceof Customer)) {
+            return false;
+        }
+        Customer customer = (Customer) o;
+        return Objects.equals(id, customer.id);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(id);
+    }
+}

spring-rest-http/src/main/java/com/baeldung/service/CustomerIdGenerator.java

@@ -0,0 +1,6 @@
+package com.baeldung.service;
+
+public interface CustomerIdGenerator {
+    int generateNextId();
+}
+

spring-rest-http/src/main/java/com/baeldung/service/CustomerService.java

@@ -0,0 +1,14 @@
+package com.baeldung.service;
+
+import com.baeldung.model.Customer;
+
+import java.util.Optional;
+
+public interface CustomerService {
+
+    Customer createCustomer(Customer customer);
+
+    Optional<Customer> findCustomer(String id);
+
+    void updateCustomer(Customer customer);
+}

spring-rest-http/src/main/java/com/baeldung/service/impl/CustomerIdGeneratorImpl.java

@@ -0,0 +1,17 @@
+package com.baeldung.service.impl;
+
+import com.baeldung.service.CustomerIdGenerator;
+
+import org.springframework.stereotype.Component;
+
+import java.util.concurrent.atomic.AtomicInteger;
+
+@Component
+public class CustomerIdGeneratorImpl implements CustomerIdGenerator {
+    private static final AtomicInteger SEQUENCE = new AtomicInteger();
+
+    @Override
+    public int generateNextId() {
+        return SEQUENCE.incrementAndGet();
+    }
+}

spring-rest-http/src/main/java/com/baeldung/service/impl/CustomerServiceImpl.java

@@ -0,0 +1,42 @@
+package com.baeldung.service.impl;
+
+import com.baeldung.model.Customer;
+import com.baeldung.service.CustomerIdGenerator;
+import com.baeldung.service.CustomerService;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Service;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Optional;
+
+@Service
+public class CustomerServiceImpl implements CustomerService {
+    private CustomerIdGenerator customerIdGenerator;
+    private List<Customer> customers = new ArrayList<>();
+
+    @Autowired
+    public CustomerServiceImpl(CustomerIdGenerator customerIdGenerator) {
+        this.customerIdGenerator = customerIdGenerator;
+    }
+
+    @Override
+    public Customer createCustomer(Customer customer) {
+        customer.setId(Integer.toString(customerIdGenerator.generateNextId()));
+        customers.add(customer);
+        return customer;
+    }
+
+    @Override
+    public Optional<Customer> findCustomer(String id) {
+        return customers.stream()
+                        .filter(customer -> customer.getId().equals(id))
+                        .findFirst();
+    }
+
+    @Override
+    public void updateCustomer(Customer customer) {
+        customers.set(customers.indexOf(customer), customer);
+    }
+}

spring-rest-http/src/main/java/com/baeldung/web/controller/CustomerRestController.java

@@ -0,0 +1,69 @@
+package com.baeldung.web.controller;
+
+import com.baeldung.model.Customer;
+import com.baeldung.service.CustomerService;
+import com.baeldung.web.exception.CustomerNotFoundException;
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.github.fge.jsonpatch.JsonPatch;
+import com.github.fge.jsonpatch.JsonPatchException;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.MediaType;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.PatchMapping;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.RequestBody;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
+import org.springframework.web.servlet.support.ServletUriComponentsBuilder;
+
+import java.net.URI;
+
+import javax.validation.Valid;
+
+@RestController
+@RequestMapping(value = "/customers")
+public class CustomerRestController {
+    private CustomerService customerService;
+    private ObjectMapper objectMapper = new ObjectMapper();
+
+    @Autowired
+    public CustomerRestController(CustomerService customerService) {
+        this.customerService = customerService;
+    }
+
+    @PostMapping(consumes = MediaType.APPLICATION_JSON_VALUE)
+    public ResponseEntity<Customer> createCustomer(@RequestBody Customer customer) {
+        Customer customerCreated = customerService.createCustomer(customer);
+        URI location = ServletUriComponentsBuilder.fromCurrentRequest()
+                                                  .path("/{id}")
+                                                  .buildAndExpand(customerCreated.getId())
+                                                  .toUri();
+        return ResponseEntity.created(location).build();
+    }
+
+    @PatchMapping(path = "/{id}", consumes = "application/json-patch+json")
+    public ResponseEntity<Customer> updateCustomer(@PathVariable String id,
+                                                   @RequestBody JsonPatch patch) {
+        try {
+            Customer customer = customerService.findCustomer(id).orElseThrow(CustomerNotFoundException::new);
+            Customer customerPatched = applyPatchToCustomer(patch, customer);
+            customerService.updateCustomer(customerPatched);
+
+            return ResponseEntity.ok(customerPatched);
+        } catch (CustomerNotFoundException e) {
+            return ResponseEntity.status(HttpStatus.NOT_FOUND).build();
+        } catch (JsonPatchException | JsonProcessingException e) {
+            return ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR).build();
+        }
+    }
+
+    private Customer applyPatchToCustomer(JsonPatch patch, Customer targetCustomer) throws JsonPatchException, JsonProcessingException {
+        JsonNode patched = patch.apply(objectMapper.convertValue(targetCustomer, JsonNode.class));
+        return objectMapper.treeToValue(patched, Customer.class);
+    }
+}

spring-rest-http/src/main/java/com/baeldung/web/exception/CustomerNotFoundException.java

@@ -0,0 +1,5 @@
+package com.baeldung.web.exception;
+
+public class CustomerNotFoundException extends RuntimeException {
+
+}

spring-rest-http/src/test/java/com/baeldung/service/impl/CustomerIdGeneratorImplUnitTest.java

@@ -0,0 +1,17 @@
+package com.baeldung.service.impl;
+
+import com.baeldung.service.CustomerIdGenerator;
+
+import org.junit.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class CustomerIdGeneratorImplUnitTest {
+
+    @Test
+    public void givenIdGeneratedPreviously_whenGenerated_thenIdIsIncremented(){
+        CustomerIdGenerator customerIdGenerator = new CustomerIdGeneratorImpl();
+        int firstId = customerIdGenerator.generateNextId();
+        assertThat(customerIdGenerator.generateNextId()).isEqualTo(++firstId);
+    }
+}

spring-rest-http/src/test/java/com/baeldung/service/impl/CustomerServiceImplUnitTest.java

@@ -0,0 +1,94 @@
+package com.baeldung.service.impl;
+
+
+import com.baeldung.model.Customer;
+import com.baeldung.service.CustomerIdGenerator;
+import com.baeldung.service.CustomerService;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.junit.MockitoJUnitRunner;
+
+import java.util.HashMap;
+import java.util.Map;
+
+
+import static com.baeldung.model.Customer.fromCustomer;
+import static java.util.Arrays.asList;
+import static java.util.Optional.empty;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.BDDMockito.given;
+
+@RunWith(MockitoJUnitRunner.class)
+public class CustomerServiceImplUnitTest {
+
+    @Mock
+    private CustomerIdGenerator mockCustomerIdGenerator;
+
+    private CustomerService customerService;
+
+    @Before
+    public void setup() {
+        customerService = new CustomerServiceImpl(mockCustomerIdGenerator);
+    }
+
+    @Test
+    public void whenCustomerIsCreated_thenNewCustomerDetailsAreCorrect() {
+        Map<String, Boolean> communicationPreferences = new HashMap<>();
+        communicationPreferences.put("post", true);
+        communicationPreferences.put("email", true);
+        Customer customer = new Customer("001-555-1234", asList("Milk", "Eggs"), communicationPreferences);
+        given(mockCustomerIdGenerator.generateNextId()).willReturn(1);
+
+        Customer newCustomer = customerService.createCustomer(customer);
+
+        assertThat(newCustomer.getId()).isEqualTo("1");
+        assertThat(newCustomer.getTelephone()).isEqualTo("001-555-1234");
+        assertThat(newCustomer.getFavorites()).containsExactly("Milk", "Eggs");
+        assertThat(newCustomer.getCommunicationPreferences()).isEqualTo(communicationPreferences);
+    }
+
+    @Test
+    public void givenNonExistentCustomer_whenCustomerIsLookedUp_thenCustomerCanNotBeFound() {
+        assertThat(customerService.findCustomer("CUST12345")).isEqualTo(empty());
+    }
+
+    @Test
+    public void whenCustomerIsCreated_thenCustomerCanBeFound() {
+        Map<String, Boolean> communicationPreferences = new HashMap<>();
+        communicationPreferences.put("post", true);
+        communicationPreferences.put("email", true);
+        Customer customer = new Customer("001-555-1234", asList("Milk", "Eggs"), communicationPreferences);
+        given(mockCustomerIdGenerator.generateNextId()).willReturn(7890);
+
+        customerService.createCustomer(customer);
+        Customer lookedUpCustomer = customerService.findCustomer("7890").get();
+
+        assertThat(lookedUpCustomer.getId()).isEqualTo("7890");
+        assertThat(lookedUpCustomer.getTelephone()).isEqualTo("001-555-1234");
+        assertThat(lookedUpCustomer.getFavorites()).containsExactly("Milk", "Eggs");
+        assertThat(lookedUpCustomer.getCommunicationPreferences()).isEqualTo(communicationPreferences);
+    }
+
+    @Test
+    public void whenCustomerUpdated_thenDetailsUpdatedCorrectly() {
+        given(mockCustomerIdGenerator.generateNextId()).willReturn(7890);
+        Map<String, Boolean> communicationPreferences = new HashMap<>();
+        communicationPreferences.put("post", true);
+        communicationPreferences.put("email", true);
+        Customer customer = new Customer("001-555-1234", asList("Milk", "Eggs"), communicationPreferences);
+        Customer newCustomer = customerService.createCustomer(customer);
+
+        Customer customerWithUpdates = fromCustomer(newCustomer);
+        customerWithUpdates.setTelephone("001-555-6789");
+        customerService.updateCustomer(customerWithUpdates);
+        Customer lookedUpCustomer = customerService.findCustomer("7890").get();
+
+        assertThat(lookedUpCustomer.getId()).isEqualTo("7890");
+        assertThat(lookedUpCustomer.getTelephone()).isEqualTo("001-555-6789");
+        assertThat(lookedUpCustomer.getFavorites()).containsExactly("Milk", "Eggs");
+        assertThat(lookedUpCustomer.getCommunicationPreferences()).isEqualTo(communicationPreferences);
+    }
+}

spring-rest-http/src/test/java/com/baeldung/web/controller/CustomerRestControllerIntegrationTest.java

@@ -0,0 +1,72 @@
+package com.baeldung.web.controller;
+
+import com.baeldung.model.Customer;
+import com.baeldung.service.CustomerService;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.boot.test.web.client.TestRestTemplate;
+import org.springframework.http.HttpEntity;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpMethod;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.MediaType;
+import org.springframework.http.ResponseEntity;
+import org.springframework.http.client.HttpComponentsClientHttpRequestFactory;
+import org.springframework.test.context.junit4.SpringRunner;
+
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.Map;
+
+import static java.util.Collections.emptyList;
+import static org.assertj.core.api.Assertions.assertThat;
+
+@RunWith(SpringRunner.class)
+@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
+public class CustomerRestControllerIntegrationTest {
+
+    @Autowired
+    private CustomerService customerService;
+
+    @Autowired
+    private TestRestTemplate testRestTemplate;
+
+    @Before
+    public void setup() {
+        testRestTemplate.getRestTemplate().setRequestFactory(new HttpComponentsClientHttpRequestFactory());
+    }
+
+    @Test
+    public void givenExistingCustomer_whenPatched_thenOnlyPatchedFieldsUpdated() {
+        Map<String, Boolean> communicationPreferences = new HashMap<>();
+        communicationPreferences.put("post", true);
+        communicationPreferences.put("email", true);
+        Customer newCustomer = new Customer("001-555-1234", Arrays.asList("Milk", "Eggs"),
+                                          communicationPreferences);
+        Customer customer = customerService.createCustomer(newCustomer);
+
+
+        String patchBody = "[ { \"op\": \"replace\", \"path\": \"/telephone\", \"value\": \"001-555-5678\" },\n"
+                           + "{\"op\": \"add\", \"path\": \"/favorites/0\", \"value\": \"Bread\" }]";
+        HttpHeaders headers = new HttpHeaders();
+        headers.setContentType(MediaType.valueOf("application/json-patch+json"));
+        ResponseEntity<Customer> patchResponse
+                = testRestTemplate.exchange("/customers/{id}",
+                                            HttpMethod.PATCH,
+                                            new HttpEntity<>(patchBody, headers),
+                                            Customer.class,
+                                            customer.getId());
+
+        Customer customerPatched = patchResponse.getBody();
+        assertThat(patchResponse.getStatusCode()).isEqualTo(HttpStatus.OK);
+        assertThat(customerPatched.getId()).isEqualTo(customer.getId());
+        assertThat(customerPatched.getTelephone()).isEqualTo("001-555-5678");
+        assertThat(customerPatched.getCommunicationPreferences().get("post")).isTrue();
+        assertThat(customerPatched.getCommunicationPreferences().get("email")).isTrue();
+        assertThat(customerPatched.getFavorites()).containsExactly("Bread", "Milk", "Eggs");
+    }
+}

spring-rest-http/src/test/java/com/baeldung/web/controller/CustomerRestControllerUnitTest.java

@@ -0,0 +1,101 @@
+package com.baeldung.web.controller;
+
+import com.baeldung.model.Customer;
+import com.baeldung.service.CustomerService;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.autoconfigure.web.servlet.AutoConfigureMockMvc;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.boot.test.mock.mockito.MockBean;
+import org.springframework.context.ApplicationContext;
+import org.springframework.test.context.junit4.SpringRunner;
+import org.springframework.test.web.servlet.MockMvc;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import static java.util.Arrays.asList;
+import static java.util.Optional.empty;
+import static java.util.Optional.of;
+import static org.hamcrest.CoreMatchers.is;
+import static org.mockito.BDDMockito.given;
+import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.patch;
+import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.post;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.jsonPath;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.redirectedUrlPattern;
+import static org.springframework.http.MediaType.APPLICATION_JSON;
+
+@RunWith(SpringRunner.class)
+@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
+@AutoConfigureMockMvc
+public class CustomerRestControllerUnitTest {
+
+    private static final String APPLICATION_JSON_PATCH_JSON = "application/json-patch+json";
+
+    @Autowired
+    private MockMvc mvc;
+
+    @MockBean
+    private CustomerService mockCustomerService;
+
+    @Autowired
+    ApplicationContext context;
+
+    @Test
+    public void whenCustomerCreated_then201ReturnedWithNewCustomerLocation() throws Exception {
+        Map<String, Boolean> communicationPreferences = new HashMap<>();
+        communicationPreferences.put("post", true);
+        communicationPreferences.put("email", true);
+        Customer customer = new Customer("001-555-1234", asList("Milk", "Eggs"), communicationPreferences);
+
+        Customer persistedCustomer = Customer.fromCustomer(customer);
+        persistedCustomer.setId("1");
+
+        given(mockCustomerService.createCustomer(customer)).willReturn(persistedCustomer);
+
+        String createCustomerRequestBody = "{"
+                                           + "\"telephone\": \"001-555-1234\",\n"
+                                           + "\"favorites\": [\"Milk\", \"Eggs\"],\n"
+                                           + "\"communicationPreferences\": {\"post\":true, \"email\":true}\n"
+                                           + "}";
+        mvc.perform(post("/customers")
+                            .contentType(APPLICATION_JSON)
+                            .content(createCustomerRequestBody))
+           .andExpect(status().isCreated())
+           .andExpect(redirectedUrlPattern("http://*/customers/1"));
+    }
+
+    @Test
+    public void givenNonExistentCustomer_whenPatched_then404Returned() throws Exception {
+        given(mockCustomerService.findCustomer("1")).willReturn(empty());
+
+        String patchInstructions = "[{\"op\":\"replace\",\"path\": \"/telephone\",\"value\":\"001-555-5678\"}]";
+        mvc.perform(patch("/customers/1")
+                            .contentType(APPLICATION_JSON_PATCH_JSON)
+                            .content(patchInstructions))
+           .andExpect(status().isNotFound());
+    }
+
+    @Test
+    public void givenExistingCustomer_whenPatched_thenReturnPatchedCustomer() throws Exception {
+        Map<String, Boolean> communicationPreferences = new HashMap<>();
+        communicationPreferences.put("post", true);
+        communicationPreferences.put("email", true);
+        Customer customer = new Customer("1", "001-555-1234", asList("Milk", "Eggs"), communicationPreferences);
+
+        given(mockCustomerService.findCustomer("1")).willReturn(of(customer));
+
+        String patchInstructions = "[{\"op\":\"replace\",\"path\": \"/telephone\",\"value\":\"001-555-5678\"}]";
+        mvc.perform(patch("/customers/1")
+                            .contentType(APPLICATION_JSON_PATCH_JSON)
+                            .content(patchInstructions))
+           .andExpect(status().isOk())
+           .andExpect(jsonPath("$.id", is("1")))
+           .andExpect(jsonPath("$.telephone", is("001-555-5678")))
+           .andExpect(jsonPath("$.favorites", is(asList("Milk", "Eggs"))))
+           .andExpect(jsonPath("$.communicationPreferences", is(communicationPreferences)));
+    }
+}