Java: Convert JSON to DTO Object

Use Jakson

U can convert JSON to DTO and back automatically with ObjectMapper:

• Convert Java object to JSON, writeValue(...)
• Convert JSON to Java object, readValue(...)
• Convert JSON to List of Java objects, readValues(...)

U can use field with different name with @JsonProperty(...) annotation.
U can skip unneeded properties with the following method: configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);

Convert JSON to DTO

   public class JsonToDtoTest {

      String usersJSON = "[" +
                            "{" +
                               "\"userId\":\"23746376473L\"," +
                               "\"username\":\"Joe\"," +
                               "\"phone\":\"43287377\"," +
                               "\"created\":\"2016-01-21T10:40:04.623Z\"" +
                            "}," +
                            "{" +
                               "\"userId\":\"23746376473L\"," +
                               "\"username\":\"Joe\"," +
                               "\"phone\":\"43287377\"," +
                               "\"created\":\"2016-01-21T10:40:04.623Z\"" +
                            "}]";

      class UserDto {

        @JsonProperty("userId")
        Long id;
        String username;

        public Long getId() { return id; }

        public void setId(Long id) {
            this.id = id;
        }

        public String getUsername() { return username; }

        public void setUsername(String username) {
            this.username = username;
        }

        @Override
        public String toString() {
            return "UserDto { id=" + id + "username=" + username + "};"
        }
      }

      @Test
      public void testParseJSON() throws Exception {
        ObjectMapper mapper = new ObjectMapper();
        mapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);

        ObjectReader reader = mapper.reader(UserDto.class);
        MappingIterator elements = reader.readValues(usersJSON);
        UserDto user = elements.next();
        Assert.assertEquals("23746376473L", user.getId());
        Assert.assertEquals("Joe", user.getUsername());
      }
    }

Deserialize an array of objects

    ...
    JavaType type = mapper.getTypeFactory().constructCollectionType(List.class, UserDto.class);
    List users = mapper.readValue(usersJSON, type);

## see Also * [Generate POJOb from JSON or JSON-Schema](http://www.jsonschema2pojo.org/) * [Github - Jackson-Annotations](https://github.com/FasterXML/jackson-annotations/wiki/Jackson-Annotations) * [Mkyong - How to convert Java object to / from JSON (Jackson)](http://www.mkyong.com/java/how-to-convert-java-object-to-from-json-jackson/) * [All Http Status Codes](http://www.restapitutorial.com/httpstatuscodes.html) * [Spring 4 API - HttpStatus](https://docs.spring.io/spring/docs/current/javadoc-api/org/springframework/http/HttpStatus.html) * [Java EE 7 API - Response.Status](http://docs.oracle.com/javaee/7/api/javax/ws/rs/core/Response.Status.html) * [Apache Commons - HttpStatus](https://hc.apache.org/httpcomponents-core-ga/httpcore/apidocs/org/apache/http/HttpStatus.html) * [REST (Restful Web Services) ](http://bloomlab.blogspot.com.ee/2015/07/rest-restfull-webservices.html) * [Themeleaf - Offsite](http://www.thymeleaf.org/) * [Web Resource Optimizer for Java](http://alexo.github.io/wro4j/) * [Wro4j - Github](https://github.com/wro4j/wro4j) * [Keynote: Top JS frmeworks 2015](http://bloomlab.blogspot.com.ee/2015/03/top-javascript-frameworks-2015.html)