Where does the member parameter come from?-CodePudding

GroupsDTO:

@Value
@Jacksonized
@Builder
@JsonIgnoreProperties(ignoreUnknown = true)
public class GroupsDTO {

    Response response;

    @Value
    @Jacksonized
    @Builder
    public static class Response {

        int count;

        @JsonProperty("items")
        List<GroupDTO> groups;

    }

}

GroupDTO:

@Jacksonized
@Builder
@Value
@JsonIgnoreProperties(ignoreUnknown = true)
public class GroupDTO {

    int id;

    @JsonProperty("is_member")
    boolean isMember;

}

I have controller:

    @ResponseStatus(HttpStatus.OK)
    @GetMapping(value = "/load"/*, produces = MediaType.APPLICATION_NDJSON_VALUE*/)
    public Mono<GroupsDTO> loadGroups() {

        var group1 = GroupDTO.builder()
                .id(1)
                .isMember(true)
                .build();

        var group2 = GroupDTO.builder()
                .id(2)
                .isMember(false)
                .build();

        var response = GroupsDTO.Response.builder()
                .count(1)
                .groups(List.of(group1, group2))
                .build();

        var groups = GroupsDTO.builder()
                .response(response)
                .build();

        return Mono.just(groups);
    }

build.gradle:

plugins {
    id 'org.springframework.boot' version '3.0.0-SNAPSHOT'
    id 'io.spring.dependency-management' version '1.0.13.RELEASE'
    id 'java'
}
//    ...
dependencies {
    implementation 'org.springframework.boot:spring-boot-starter-webflux'
    implementation 'org.springframework.boot:spring-boot-starter-data-jpa'
    implementation 'org.springframework.boot:spring-boot-starter-validation'
    compileOnly 'org.projectlombok:lombok'
    developmentOnly 'org.springframework.boot:spring-boot-devtools'
    runtimeOnly 'org.postgresql:postgresql'
    annotationProcessor 'org.springframework.boot:spring-boot-configuration-processor'
    annotationProcessor 'org.projectlombok:lombok'
    testImplementation 'org.springframework.boot:spring-boot-starter-test'
    testImplementation 'io.projectreactor:reactor-test'
}

json on perform /load

{"response":{"count":1,"items":[{"id":1,"member":true,"is_member":true},{"id":2,"member":false,"is_member":false}]}}

Where does the member parameter come from ?

CodePudding user response：

In the JavaBeans standard, a boolean property member would have a getter called isMember(); a boolean property named isMember would have a getter called isIsMember(). Lombok, however(), figures that you probably want isMember() instead of isIsMember (a reasonable guess).

You annotated your class with Lombok's @Value, which auto-creates the get/set methods that formally define a property based on the member fields. Jackson sees your boolean field isMember, which is annotated with @JsonProperty, and it renames the JSON property accordingly, but it also sees a method boolean isMember(), which it interprets as a property named member, so you get your duplicate output.

Try renaming your field boolean member to match the JavaBeans conventions.