Jackson与Lombok：解决布尔类型字段默认值反序列化为Null的问题

@Data
@AllArgsConstructor
@ApiModel
public class RelationEntityTypeFilter {
    // ... 其他字段 ...

    @ApiModelProperty(position = 3, value = "Negate relation type between root entity and other entity.")
    private Boolean negate = false; // 期望默认值为 false
}

@NoArgsConstructor // Lombok注解，用于生成无参构造器
@Getter // Lombok注解，用于生成getter方法
@Setter // Lombok注解，用于生成setter方法
@ToString // Lombok注解，用于生成toString方法
public static class RelationEntityTypeFilter {
    private boolean negate; // 将 Boolean 改为 boolean
}

import com.fasterxml.jackson.databind.ObjectMapper;
import lombok.Getter;
import lombok.NoArgsConstructor;
import lombok.Setter;
import lombok.ToString;

public class JacksonBooleanDeserializationExample {

    @NoArgsConstructor
    @Getter
    @Setter
    @ToString
    public static class RelationEntityTypeFilter {
        private boolean negate; // 核心改动：使用基本类型 boolean
        private String relationType; // 添加其他字段以模拟真实场景
    }

    public static void main(String[] args) throws Exception {
        ObjectMapper mapper = new ObjectMapper();

        // 场景一：JSON中缺少 'negate' 字段
        String jsonMissingNegate = "{ \"relationType\": \"Contains\" }";
        RelationEntityTypeFilter filter1 = mapper.readValue(jsonMissingNegate, RelationEntityTypeFilter.class);
        System.out.println("JSON (missing negate): " + filter1);

        // 场景二：JSON中 'negate' 字段明确为 false
        String jsonExplicitFalse = """
            {
                "relationType": "Contains",
                "negate" : false
            }
            """;
        RelationEntityTypeFilter filter2 = mapper.readValue(jsonExplicitFalse, RelationEntityTypeFilter.class);
        System.out.println("JSON (negate is false): " + filter2);

        // 场景三：JSON中 'negate' 字段明确为 true
        String jsonExplicitTrue = """
            {
                "relationType": "Contains",
                "negate" : true
            }
            """;
        RelationEntityTypeFilter filter3 = mapper.readValue(jsonExplicitTrue, RelationEntityTypeFilter.class);
        System.out.println("JSON (negate is true): " + filter3);
    }
}

JSON (missing negate): RelationEntityTypeFilter(negate=false, relationType=Contains)
JSON (negate is false): RelationEntityTypeFilter(negate=false, relationType=Contains)
JSON (negate is true): RelationEntityTypeFilter(negate=true, relationType=Contains)