Code for Jackson post (#197)

* add the initial maven project

* add a few code examples

* add a few code examples

* add a few code examples

* add a few code examples

* add a few code examples

* add JsonAnyGetter example

core-java/jackson/jackson/.gitignore

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+HELP.md
+target/*
+!.mvn/wrapper/maven-wrapper.jar
+!**/src/main/**/target/
+!**/src/test/**/target/
+
+.classpath
+.factorypath
+.project
+.settings
+.springBeans
+
+### IntelliJ IDEA ###
+.idea
+*.iws
+*.iml
+*.ipr
+
+### NetBeans ###
+/nbproject/private/
+/nbbuild/
+/dist/
+/nbdist/
+build/
+!**/src/main/**/build/
+!**/src/test/**/build/
+
+### VS Code ###
+.vscode/

core-java/jackson/jackson/pom.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <groupId>com.reflectoring</groupId>
+    <artifactId>jackson</artifactId>
+    <version>1.0-SNAPSHOT</version>
+
+    <properties>
+        <maven.compiler.source>11</maven.compiler.source>
+        <maven.compiler.target>11</maven.compiler.target>
+    </properties>
+
+    <dependencies>
+        <dependency>
+            <groupId>com.fasterxml.jackson.core</groupId>
+            <artifactId>jackson-databind</artifactId>
+            <version>2.13.3</version>
+        </dependency>
+
+        <dependency>
+            <groupId>com.fasterxml.jackson.datatype</groupId>
+            <artifactId>jackson-datatype-jsr310</artifactId>
+            <version>2.13.3</version>
+        </dependency>
+
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter-api</artifactId>
+            <version>5.9.0-M1</version>
+            <scope>test</scope>
+        </dependency>
+
+        <dependency>
+            <groupId>org.projectlombok</groupId>
+            <artifactId>lombok</artifactId>
+            <version>1.18.24</version>
+            <scope>provided</scope>
+        </dependency>
+
+        <dependency>
+            <groupId>org.assertj</groupId>
+            <artifactId>assertj-core</artifactId>
+            <version>3.23.1</version>
+            <scope>test</scope>
+        </dependency>
+
+
+    </dependencies>
+</project>

core-java/jackson/jackson/src/main/java/com/reflectoring/pojo/Car.java

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+package com.reflectoring.pojo;
+
+import com.fasterxml.jackson.annotation.JsonAnySetter;
+import com.fasterxml.jackson.annotation.JsonSetter;
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+
+import java.util.HashMap;
+import java.util.Map;
+
+@NoArgsConstructor
+@AllArgsConstructor
+@Getter
+public class Car {
+    @JsonSetter("carBrand")
+    private String brand;
+    private Map<String, String> unrecognizedFields = new HashMap<>();
+
+    @JsonAnySetter
+    public void allSetter(String fieldName, String fieldValue) {
+        unrecognizedFields.put(fieldName, fieldValue);
+    }
+}

core-java/jackson/jackson/src/main/java/com/reflectoring/pojo/Cat.java

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+package com.reflectoring.pojo;
+
+import com.fasterxml.jackson.annotation.JsonAnyGetter;
+import com.fasterxml.jackson.annotation.JsonGetter;
+import lombok.AllArgsConstructor;
+import lombok.NoArgsConstructor;
+
+import java.util.Map;
+
+@NoArgsConstructor
+@AllArgsConstructor
+public class Cat {
+    private String name;
+
+    @JsonAnyGetter
+    Map<String, String> map = Map.of(
+            "name", "Jack",
+            "surname", "wolfskin"
+    );
+
+    @JsonGetter("catName")
+    public String getName() {
+        return name;
+    }
+
+    public Cat(String name) {
+        this.name = name;
+    }
+}

core-java/jackson/jackson/src/main/java/com/reflectoring/pojo/Dog.java

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+package com.reflectoring.pojo;
+
+import com.fasterxml.jackson.annotation.JsonIgnore;
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+
+@AllArgsConstructor
+@NoArgsConstructor
+@Getter
+public class Dog {
+    private String name;
+    @JsonIgnore
+    private Integer age;
+}

core-java/jackson/jackson/src/main/java/com/reflectoring/pojo/Employee.java

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+package com.reflectoring.pojo;
+
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+
+import java.util.Date;
+
+@Getter
+@AllArgsConstructor
+@NoArgsConstructor
+public class Employee {
+    private String firstName;
+    private String lastName;
+    private int age;
+}

core-java/jackson/jackson/src/main/java/com/reflectoring/pojo/Order.java

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+package com.reflectoring.pojo;
+
+import com.fasterxml.jackson.annotation.JsonFormat;
+import com.fasterxml.jackson.annotation.JsonSetter;
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+
+import java.time.LocalDate;
+
+@NoArgsConstructor
+@AllArgsConstructor
+@Getter
+public class Order {
+    private int id;
+    @JsonFormat(pattern = "dd/MM/yyyy")
+    private LocalDate date;
+}

core-java/jackson/jackson/src/test/java/com/reflectoring/JacksonTest.java

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+package com.reflectoring;
+
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.core.type.TypeReference;
+import com.fasterxml.jackson.databind.DeserializationFeature;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.reflectoring.pojo.*;
+import org.junit.jupiter.api.Test;
+
+import java.io.File;
+import java.io.IOException;
+import java.time.LocalDate;
+import java.util.List;
+import java.util.Map;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class JacksonTest {
+    ObjectMapper objectMapper = new ObjectMapper().findAndRegisterModules();
+
+    @Test
+    void jsonStringToPojo() throws JsonProcessingException {
+        String employeeJson = "{\n" +
+                " \"firstName\" : \"Jalil\",\n" +
+                "  \"lastName\" : \"Jarjanazy\",\n" +
+                "  \"age\" : 30\n" +
+                "}";
+
+        Employee employee = objectMapper.readValue(employeeJson, Employee.class);
+
+        assertThat(employee.getFirstName()).isEqualTo("Jalil");
+    }
+
+    @Test
+    void pojoToJsonString() throws JsonProcessingException {
+        Employee employee = new Employee("Mark", "James", 20);
+
+        String json = objectMapper.writeValueAsString(employee);
+
+        assertThat(json).isEqualTo("{\"firstName\":\"Mark\",\"lastName\":\"James\",\"age\":20}");
+    }
+
+    @Test
+    void jsonFileToPojo() throws IOException {
+        File file = new File("src/test/resources/employee.json");
+
+        Employee employee = objectMapper.readValue(file, Employee.class);
+
+        assertThat(employee.getAge()).isEqualTo(44);
+        assertThat(employee.getLastName()).isEqualTo("Simpson");
+        assertThat(employee.getFirstName()).isEqualTo("Homer");
+    }
+
+    @Test
+    void byteArrayToPojo() throws IOException {
+        String employeeJson = "{\n" +
+                " \"firstName\" : \"Jalil\",\n" +
+                "  \"lastName\" : \"Jarjanazy\",\n" +
+                "  \"age\" : 30\n" +
+                "}";
+
+        Employee employee = objectMapper.readValue(employeeJson.getBytes(), Employee.class);
+
+        assertThat(employee.getFirstName()).isEqualTo("Jalil");
+    }
+
+    @Test
+    void fileToListOfPojos() throws IOException {
+        File file = new File("src/test/resources/employeeList.json");
+        List<Employee> employeeList = objectMapper.readValue(file, new TypeReference<>(){});
+
+        assertThat(employeeList).hasSize(2);
+        assertThat(employeeList.get(0).getAge()).isEqualTo(33);
+        assertThat(employeeList.get(0).getLastName()).isEqualTo("Simpson");
+        assertThat(employeeList.get(0).getFirstName()).isEqualTo("Marge");
+    }
+
+    @Test
+    void fileToMap() throws IOException {
+        File file = new File("src/test/resources/employee.json");
+        Map<String, Object> employee = objectMapper.readValue(file, new TypeReference<>(){});
+
+        assertThat(employee.keySet()).containsExactly("firstName", "lastName", "age");
+
+        assertThat(employee.get("firstName")).isEqualTo("Homer");
+        assertThat(employee.get("lastName")).isEqualTo("Simpson");
+        assertThat(employee.get("age")).isEqualTo(44);
+    }
+
+    @Test
+    void fileToPojoWithUnknownProperties() throws IOException {
+        File file = new File("src/test/resources/employeeWithUnknownProperties.json");
+
+        objectMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
+
+        Employee employee = objectMapper.readValue(file, Employee.class);
+
+        assertThat(employee.getFirstName()).isEqualTo("Homer");
+        assertThat(employee.getLastName()).isEqualTo("Simpson");
+        assertThat(employee.getAge()).isEqualTo(44);
+    }
+
+    @Test
+    void orderToJson() throws JsonProcessingException {
+        Order order = new Order(1, LocalDate.of(1900,2,1));
+
+        String json = objectMapper.writeValueAsString(order);
+
+        System.out.println(json);
+    }
+
+    @Test
+    void orderToJsonWithDate() throws JsonProcessingException {
+        Order order = new Order(1, LocalDate.of(2023, 1, 1));
+
+        String json = objectMapper.writeValueAsString(order);
+
+        System.out.println(json);
+    }
+    @Test
+    void fileToOrder() throws IOException {
+        File file = new File("src/test/resources/order.json");
+
+        Order order = objectMapper.readValue(file, Order.class);
+
+        assertThat(order.getDate().getYear()).isEqualTo(2000);
+        assertThat(order.getDate().getMonthValue()).isEqualTo(4);
+        assertThat(order.getDate().getDayOfMonth()).isEqualTo(30);
+    }
+    @Test
+    void fileToCar() throws IOException {
+        File file = new File("src/test/resources/car.json");
+
+        Car car = objectMapper.readValue(file, Car.class);
+
+        assertThat(car.getBrand()).isEqualTo("BMW");
+    }
+
+    @Test
+    void fileToUnrecognizedCar() throws IOException {
+        File file = new File("src/test/resources/carUnrecognized.json");
+
+        Car car = objectMapper.readValue(file, Car.class);
+
+        assertThat(car.getUnrecognizedFields()).containsKey("productionYear");
+    }
+
+    @Test
+    void catToJson() throws JsonProcessingException {
+        Cat cat = new Cat("Monica");
+
+        String json = objectMapper.writeValueAsString(cat);
+
+        System.out.println(json);
+
+    }
+
+    @Test
+    void catToJsonWithMap() throws JsonProcessingException {
+        Cat cat = new Cat("Monica");
+
+        String json = objectMapper.writeValueAsString(cat);
+
+        System.out.println(json);
+    }
+
+    @Test
+    void dogToJson() throws JsonProcessingException {
+        Dog dog = new Dog("Max", 3);
+
+        String json = objectMapper.writeValueAsString(dog);
+
+        System.out.println(json);
+    }
+    @Test
+    void fileToDog() throws IOException {
+        File file = new File("src/test/resources/dog.json");
+
+        Dog dog = objectMapper.readValue(file, Dog.class);
+
+        assertThat(dog.getName()).isEqualTo("bobby");
+        assertThat(dog.getAge()).isNull();
+    }
+}

core-java/jackson/jackson/src/test/resources/car.json

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+{
+  "carBrand" : "BMW"
+}

core-java/jackson/jackson/src/test/resources/carUnrecognized.json

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+{
+  "carBrand" : "BMW",
+  "productionYear": 1996
+}

core-java/jackson/jackson/src/test/resources/dog.json

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+{
+  "name" : "bobby",
+  "age" : 5
+}

core-java/jackson/jackson/src/test/resources/employee.json

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+{
+  "firstName":"Homer",
+  "lastName":"Simpson",
+  "age":44
+}

core-java/jackson/jackson/src/test/resources/employeeList.json

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+[
+  {
+    "firstName":"Marge",
+    "lastName":"Simpson",
+    "age":33
+  },
+  {
+  "firstName":"Homer",
+  "lastName":"Simpson",
+  "age":44
+  }
+]

core-java/jackson/jackson/src/test/resources/employeeWithUnknownProperties.json

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+{
+  "firstName":"Homer",
+  "lastName":"Simpson",
+  "age":44,
+  "department": "IT"
+}

core-java/jackson/jackson/src/test/resources/order.json

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+{
+  "id" : 1,
+  "date" : "30/04/2000"
+}