Spring Web MVC produces error with parameter names including square brackets

01-spring-web-tester-param-names-with-square-brackets-error

$.ajax({
    url: 'http://localhost:8080/data-binder',
    contentType: 'application/json',
    method: 'GET',
    crossDomain: true,
    data: {
        id: "321",
        addresses: [
            {
                city: "Seoul",
                goo: "Peace",
                street: "Forever",
                number: 3
            },
            {
                city: "Incheon",
                goo: "Hapiness",
                street: "Together",
                number: 33
            }
        ],
        emails: ['abc@abc.com', 'sdf@sdf.com']
    }
}).done(function(msg) {
    // Do something with msg
});

02-HttpRequestParameters

id:321
addresses[0][city]:Seoul
addresses[0][goo]:Peace
addresses[0][street]:Forever
addresses[0][number]:3
addresses[1][city]:Incheon
addresses[1][goo]:Hapiness
addresses[1][street]:Together
addresses[1][number]:33
emails[]:abc@abc.com
emails[]:sdf@sdf.com

03-SampleDTO.java

public class SampleDTO {

    private String id;
    private List<Address> addresses;
    private List<String> emails;

    public String getId() {
        return id;
    }

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

    public List<Address> getAddresses() {
        return addresses;
    }

    public void setAddresses(List<Address> addresses) {
        this.addresses = addresses;
    }

    public List<String> getEmails() {
        return emails;
    }

    public void setEmails(List<String> emails) {
        this.emails = emails;
    }
}

public class Address {

    private String city;
    private String goo;
    private String street;
    private String number;
    
    // getter, setter
}

04-Controller.java

@RequestMapping(value = "/data-binder", method = RequestMethod.GET, consumes = MediaType.APPLICATION_JSON_UTF8_VALUE)
public ResponseEntity<SampleDTO> saveSampleEntity(HttpServletRequest request, SampleDTO dto) {
    return ResponseEntity.ok(dto);
}

05-Error Message

org.springframework.beans.InvalidPropertyException: 
  Invalid property 'addresses[0][city]' of bean class [homo.efficio.springboot.scratchpad.jackson.model.SampleDTO]: 
    Property referenced in indexed property path 'addresses[0][city]' is neither an array nor a List nor a Map; 
      returned value was [homo.efficio.springboot.scratchpad.jackson.model.Address@3e95df7]

06-WebUtils.java

public class WebUtils {

    public static <T> T getDTOFromParamMap(Map<String, String[]> parameterMap, Class<T> dto) throws IllegalAccessException, InstantiationException {

        final MutablePropertyValues sourceProps = getPropsFrom(parameterMap);

        T targetDTO = dto.newInstance();
        DataBinder binder = new DataBinder(targetDTO);
        binder.bind(sourceProps);

        return targetDTO;
    }

    private static MutablePropertyValues getPropsFrom(Map<String, String[]> parameterMap) {
        final MutablePropertyValues mpvs = new MutablePropertyValues();

        parameterMap.forEach(
                (k, v) -> {
                    String dotKey =
                        k
                        .replaceAll("\\['", "[")
                        .replaceAll("']", "]")
                        .replaceAll("\\[\"", "[")
                        .replaceAll("\"]", "]")
                        .replaceAll("\\[]", "")
                        .replaceAll("\\[(\\d+)]", "!#%@$1%@#!")
                        .replaceAll("\\[", ".")
                        .replaceAll("]", "")
                        .replaceAll("!#%@(\\d+)%@#!", "[$1]");
                    mpvs.addPropertyValue(dotKey, v);
                }
        );

        return mpvs;
    }
}


// Test Example
@Test
public void convertSquareBracketToDot() throws Exception {

    String k = "items[0][options][1][a][12][b][abc][c][1234][c1][33][_1][___][99][a33][b3][aa3]";

    String result =
            k
            .replaceAll("\\['", "[")
            .replaceAll("']", "]")
            .replaceAll("\\[\"", "[")
            .replaceAll("\"]", "]")
            .replaceAll("\\[]", "")
            .replaceAll("\\[(\\d+)]", "!#%@$1%@#!")
            .replaceAll("\\[", ".")
            .replaceAll("]", "")
            .replaceAll("!#%@(\\d+)%@#!", "[$1]");

    Assert.assertThat(result, Matchers.is("items[0].options[1].a[12].b.abc.c[1234].c1[33]._1.___[99].a33.b3.aa3"));
}

07-ControllerWithoutError.java

@RequestMapping(value = "/data-binder", method = RequestMethod.GET, consumes = MediaType.APPLICATION_JSON_UTF8_VALUE)
public ResponseEntity<SampleDTO> saveSampleEntity(HttpServletRequest request) {

    SampleDTO dto = null;
    try {
        dto = HomoEfficioWebUtils.getDTOFromParamMap(request.getParameterMap(), SampleDTO.class);
    } catch (IllegalAccessException e) {
        e.printStackTrace();
    } catch (InstantiationException e) {
        e.printStackTrace();
    }

    return ResponseEntity.ok(dto);
}

09 - Reponse

{
    "id": "321",
    "addresses": [{
        "city": "Seoul",
        "goo": "Peace",
        "street": "Forever",
        "number": "3"
    }, {
        "city": "Incheon",
        "goo": "Hapiness",
        "street": "Together",
        "number": "33"
    }],
    "emails": ["abc@abc.com", "sdf@sdf.com"]
}