BAEL-5952-Java HttpClient - Map Json Response to Java Class (#13234)

* Java HttpClient - Map Json Response to Java Class

* BAEL-5952-Java HttpClient - Map Json Response to Java Class

* BAEL-5952-Java HttpClient - Map Json Response to Java Class

* Java HttpClient - Map Json Response to Java Class

* Java HttpClient - Map Json Response to Java Class

* Java HttpClient - Map Json Response to Java Class

* Java HttpClient - Map Json Response to Java Class

* Java HttpClient - Map Json Response to Java Class

* Java HttpClient - Map Json Response to Java Class

* Java HttpClient - Map Json Response to Java Class

* Java HttpClient - Map Json Response to Java Class

* Java HttpClient - Map Json Response to Java Class

* Java HttpClient - Map Json Response to Java Class

* Java HttpClient - Map Json Response to Java Class

* Java HttpClient - Map Json Response to Java Class

* Java HttpClient - Map Json Response to Java Class

* Java HttpClient - Map Json Response to Java Class

* Java HttpClient - Map Json Response to Java Class

core-java-modules/core-java-11-3/pom.xml

@@ -14,6 +14,20 @@
         <version>1.0.0-SNAPSHOT</version>
         <relativePath>../../pom.xml</relativePath>
     </parent>
+    
+    <dependencies>
+        <dependency>
+            <groupId>com.google.code.gson</groupId>
+            <artifactId>gson</artifactId>
+            <version>${gson.version}</version>
+        </dependency>
+        <!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-databind -->
+        <dependency>
+            <groupId>com.fasterxml.jackson.core</groupId>
+            <artifactId>jackson-databind</artifactId>
+            <version>${jackson.version}</version>
+        </dependency>
+    </dependencies>
 
     <build>
         <plugins>
@@ -32,6 +46,8 @@
     <properties>
         <maven.compiler.source.version>11</maven.compiler.source.version>
         <maven.compiler.target.version>11</maven.compiler.target.version>
+        <jackson.version>2.14.1</jackson.version>
+        <gson.version>2.10</gson.version>
     </properties>
 
 </project>

core-java-modules/core-java-11-3/src/main/java/com/baeldung/httppojo/Todo.java

@@ -0,0 +1,73 @@
+package com.baeldung.httppojo;
+
+import java.util.Objects;
+
+public class Todo {
+
+    int userId;
+    int id;
+    String title;
+    boolean completed;
+
+    public Todo() {
+    }
+
+    public Todo(int userId, int id, String title, boolean completed) {
+        this.userId = userId;
+        this.id = id;
+        this.title = title;
+        this.completed = completed;
+    }
+
+    public int getUserId() {
+        return userId;
+    }
+
+    public void setUserId(int userId) {
+        this.userId = userId;
+    }
+
+    public int getId() {
+        return id;
+    }
+
+    public void setId(int id) {
+        this.id = id;
+    }
+
+    public String getTitle() {
+        return title;
+    }
+
+    public void setTitle(String title) {
+        this.title = title;
+    }
+
+    public boolean isCompleted() {
+        return completed;
+    }
+
+    public void setCompleted(boolean completed) {
+        this.completed = completed;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o)
+            return true;
+        if (o == null || getClass() != o.getClass())
+            return false;
+        Todo todo = (Todo) o;
+        return userId == todo.userId && id == todo.id && completed == todo.completed && Objects.equals(title, todo.title);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(userId, id, title, completed);
+    }
+
+    @Override
+    public String toString() {
+        return "{" + "userId=" + userId + ", id=" + id + ", title='" + title + '\'' + ", completed=" + completed + '}';
+    }
+}

core-java-modules/core-java-11-3/src/main/java/com/baeldung/httppojo/TodoAppClient.java

@@ -0,0 +1,107 @@
+package com.baeldung.httppojo;
+
+import java.io.IOException;
+import java.net.URI;
+import java.net.http.HttpClient;
+import java.net.http.HttpRequest;
+import java.net.http.HttpResponse;
+import java.net.http.HttpResponse.BodyHandlers;
+import java.util.List;
+import java.util.concurrent.CompletionException;
+
+import com.fasterxml.jackson.core.type.TypeReference;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.google.gson.Gson;
+import com.google.gson.GsonBuilder;
+import com.google.gson.reflect.TypeToken;
+
+public class TodoAppClient {
+
+    ObjectMapper objectMapper = new ObjectMapper();
+
+    Gson gson = new GsonBuilder().create();
+
+    public String sampleApiRequest() throws Exception {
+        HttpClient client = HttpClient.newHttpClient();
+        HttpRequest request = HttpRequest.newBuilder()
+            .uri(URI.create("https://jsonplaceholder.typicode.com/todos"))
+            .build();
+
+        HttpResponse<String> response = client.send(request, BodyHandlers.ofString());
+
+        return response.body();
+
+    }
+
+    public Todo syncGson() throws Exception {
+        String response = sampleApiRequest();
+
+        List<Todo> todo = gson.fromJson(response, new TypeToken<List<Todo>>() {
+        }.getType());
+
+        return todo.get(1);
+
+    }
+
+    public Todo syncJackson() throws Exception {
+        String response = sampleApiRequest();
+
+        Todo[] todo = objectMapper.readValue(response, Todo[].class);
+
+        return todo[1];
+
+    }
+
+    public Todo asyncJackson() throws Exception {
+
+        HttpRequest request = HttpRequest.newBuilder()
+            .uri(URI.create("https://jsonplaceholder.typicode.com/todos"))
+            .build();
+
+        TodoAppClient todoAppClient = new TodoAppClient();
+
+        List<Todo> todo = HttpClient.newHttpClient()
+            .sendAsync(request, BodyHandlers.ofString())
+            .thenApply(HttpResponse::body)
+            .thenApply(todoAppClient::readValueJackson)
+            .get();
+
+        return todo.get(1);
+
+    }
+
+    public Todo asyncGson() throws Exception {
+
+        HttpRequest request = HttpRequest.newBuilder()
+            .uri(URI.create("https://jsonplaceholder.typicode.com/todos"))
+            .build();
+        TodoAppClient todoAppClient = new TodoAppClient();
+
+        List<Todo> todo = HttpClient.newHttpClient()
+            .sendAsync(request, BodyHandlers.ofString())
+            .thenApply(HttpResponse::body)
+            .thenApply(todoAppClient::readValueGson)
+            .get();
+
+        return todo.get(1);
+
+    }
+
+    List<Todo> readValueJackson(String content) {
+
+        try {
+            return objectMapper.readValue(content, new TypeReference<List<Todo>>() {
+            });
+        } catch (IOException ioe) {
+            throw new CompletionException(ioe);
+        }
+    }
+    
+    List<Todo> readValueGson(String content) {
+
+        return gson.fromJson(content, new TypeToken<List<Todo>>() {
+        }.getType());
+
+    }
+
+}

core-java-modules/core-java-11-3/src/test/java/com/baeldung/httppojo/HttpClientPojoClassUnitTest.java

@@ -0,0 +1,45 @@
+package com.baeldung.httppojo;
+
+import static org.junit.Assert.*;
+
+import org.junit.Test;
+
+public class HttpClientPojoClassUnitTest {
+
+    Todo expectedTodo = new Todo(1, 2, "quis ut nam facilis et officia qui", false);
+
+    @Test
+    public void givenSampleApiCall_whenResponseIsMappedByGson_thenCompareResponseMappedByGson() throws Exception {
+        TodoAppClient sampleGson = new TodoAppClient();
+
+        assertEquals(expectedTodo, sampleGson.syncGson());
+
+    }
+
+    @Test
+    public void givenSampleApiCall_whenResponseIsMappedByJackson_thenCompareResponseMappedByJackson() throws Exception {
+        TodoAppClient sampleJackson = new TodoAppClient();
+
+        assertEquals(expectedTodo, sampleJackson.syncJackson());
+    }
+
+    @Test
+    public void givenSampleRestApi_whenApiIsConsumedByHttpClient_thenCompareJsonString() throws Exception {
+        TodoAppClient sampleTest = new TodoAppClient();
+        assertNotNull(sampleTest.sampleApiRequest());
+
+    }
+
+    @Test
+    public void givenSampleApiAsyncCall_whenResponseIsMappedByJackson_thenCompareResponseMappedByJackson() throws Exception {
+        TodoAppClient sampleAsynJackson = new TodoAppClient();
+        assertEquals(expectedTodo, sampleAsynJackson.asyncJackson());
+    }
+
+    @Test
+    public void givenSampleApiAsyncCall_whenResponseIsMappedByGson_thenCompareResponseMappedByGson() throws Exception {
+        TodoAppClient sampleAsynGson = new TodoAppClient();
+        assertEquals(expectedTodo, sampleAsynGson.asyncGson());
+    }
+
+}