@Data
public class Employer {
    private String name;
    private Integer age;
    private String[] hobbies;
    private List<String> friends;
    private Map<String, BigDecimal> salary; 

 //initial an object
  public static Employer getInstance(){
    Employer employer = new Employer();

    employer.setName("AA");
    employer.setAge(45);
    employer.setHobbies(new String[]{"XXXX", "YYYY"});
    Map<String, BigDecimal> salary = new HashMap<String, BigDecimal>() {{
      put("2000", new BigDecimal(10000000));
      put("2010", new BigDecimal(62000000));
      put("2020", new BigDecimal(112400000));
    }};
    playerStar.setSalary(salary);
    playerStar.setFriends(Arrays.asList("BB", "CC", "DDs"));

    return employer;
  }

}

@Test
void testObject2JSON() throws IOException {
  //get an object
  Employer em1 = Employer.getInstance();

  //ObjectMapper is tool
  ObjectMapper mapper = new ObjectMapper();
  //1. serialize the employer object，store the result
  mapper.writeValue(new File("d:\data\jackson\employer.json"), em1);

  //2. return a string object
  String jsonString = mapper.writeValueAsString(em1);
  System.out.println(jsonString);

  //3. return a string object with prettyprinter
  String jsonInString2 = mapper.writerWithDefaultPrettyPrinter()
          .writeValueAsString(em1);
  System.out.println(jsonInString2);
}

@Test
void testObject2JSON() throws IOException {
  
  //ObjectMapper is tool
  ObjectMapper mapper = new ObjectMapper();

   // 1. read the JSON file, get java object 
  Employer em1 = mapper.readValue(new File("d:\data\jackson\employer.json"), Employer.class);

  //2. read from JSON directly
  String jsonString = "{\"name\":\"AA\",\"age\":45,\"hobbies\":[\"XXXX\",\"YYYY\"]}";
  Employer em1 = mapper.readValue(jsonString, Employer.class);
  System.out.println(em1);

}

@Data
public class Employer {

    @@JsonProperty("teamName")
    private String name; // {"teamName": "AA"}
   

  //2. read from JSON directly
  String jsonString = "{\"name\":\"AA\",\"age\":45,\"hobbies\":[\"XXXX\",\"YYYY\"]}";
  Employer em1 = mapper.readValue(jsonString, Employer.class);

@JsonInclude(JsonInclude.Include.NON_NULL)
public class Employer {

// {"age": 45, "teamName" : "AA"}, null property would be ignored

URL url = new URL("https://jsonplaceholder.typicode.com/posts/1");
ObjectMapper mapper = new ObjectMapper();
  //2. read from JSON directly

Employer em1 = mapper.readValue(url, Employer.class);

public class Employer {
    private String name;
    private Integer age;
    private String[] hobbies;
    private List<String> friends;
    private Map<String, BigDecimal> salary; 

//constructor
@JsonCreator
  public Employer(@JsonProperty("name") String name,
                     @JsonProperty("age") Integer age,
                     @JsonProperty("hobbies") String[] hobbies,
                     @JsonProperty("friends") List<String> friends,
                     @JsonProperty("salary") Map<String, BigDecimal> salary) {
    this.name = name;
    this.age = age;
    this.hobbies = hobbies;
    this.friends = friends;
    this.salary = salary;                     
                     }
    
  }

}

public class Employer {
    private String name;
    private Integer age;
    private String[] hobbies;
    private List<String> friends;
    private Map<String, BigDecimal> salary; 

//constructor
@JsonCreator
  public static Employer createEmployer(@JsonProperty("name") String name,
                     @JsonProperty("age") Integer age,
                     @JsonProperty("hobbies") String[] hobbies,
                     @JsonProperty("friends") List<String> friends,
                     @JsonProperty("salary") Map<String, BigDecimal> salary) {
    Employer emp = new  Employer();                  
    emp.name = name;
    emp.age = age;
    emp.hobbies = hobbies;
    emp.friends = friends;
    emp.salary = salary; 
    return emp;                    
                     }
    
  }

}

public class Employer {
    private String name;
    private Integer age;
    private String[] hobbies;
    private List<String> friends;
    private Map<String, BigDecimal> salary; 

  @ConstructorProperties({"name", "age","hobbies" , "friends", "salary"})
  public Employer(String name,
                    Integer age,
                    String[] hobbies,
                    List<String> friends,
                    Map<String, BigDecimal> salary) {
    this.name = name;
    this.age = age;
    this.hobbies = hobbies;
    this.friends = friends;
    this.salary = salary;                     
                     }
    
  }

}

@JsonSerialize(using = LocalDateTimeSerializer.class)
@JsonDeserialize(using = LocalDateTimeDeserializer.class)
private LocalDateTime birthDate;

{
    "name":"AA",
    "place":"BB",
    "birthDate":"CC",
    "departments": [{
         "name":"department",
         "local_place":"XXXX",
         "pm":"jack"
    }, {
         "name":"test",
         "local_place":"YYYY",
         "pm":"mike"
    }]
}

{
    "name":"AA",
    "place":"BB",
    "birthDate":"CC",
    "departments": [{
         "name":"department",
         "local_place":"XXXX",
         "pm":"jack"
         "employee_number":2000,
         "product" : "ii"
    }, {
         "name":"test",
         "local_place":"YYYY",
         "pm":"mike",
         "employee_number":2000,
         "product" : "ii"
    }]
}
public class Company {
    private String name;
    @JsonProperty("HQ")
    private String headquarters;
    private Department[] departments;
    @JsonIgnore
    private Date birthDate;

    @JsonCreator
    public Company(@JsonProperty("name") String name) {
        this.name = name;
    }
}

public class Department {
    private String name;
    private String pm;
    private Map<String, Object> others = new HashMap<>();

   

    @JsonCreator
    public Department(@JsonProperty("name") String name) {
        this.name = name;
    }

    @JsonProperty("projectManager")
    public String getPm() {
        return pm;
    }

    @JsonAnyGetter // get all undefined json in department
    public Map<String, Object> any() {
        return others;
    }

    @JsonAnySetter 
    public void set(String key, Object value) {
        others.put(key, value);
    }
}

public class Deserialization {
    public static void main(String[] args) throws Exception {

  
  //ObjectMapper is tool
  ObjectMapper mapper = new ObjectMapper();
  mapper.disable(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES);

  Company company = mapper.readValue(new File("d:\data\jackson\employer.json"), Company.class);

    System.out.print(company.getName());
    System.out.print(company.getHeadquarters());
    System.out.print(company.getBirthDate()); // null

    Department[] departments = company.getDepartments();

    for (Departments department : departments) {
    System.out.print(department.getName());
    System.out.print(department.getPm());
    System.out.print(department.get("employee_number"));
     System.out.print(department.get("product"));
  
    }
    }
}