Lombok对象中实现两个可选字段至少一个存在的约束

import lombok.Builder;
import lombok.Getter;
import lombok.RequiredArgsConstructor;
import javax.validation.constraints.AssertFalse; // 确保已引入javax.validation-api依赖

@Getter
@Builder
@RequiredArgsConstructor
class Example {
    private final String maybeA;
    private final String maybeB;

    /**
     * 自定义校验方法，用于检查maybeA和maybeB是否同时为空。
     * 当且仅当maybeA和maybeB都为null时，返回true，表示出现无效状态。
     * @return 如果两个字段都为空，则返回true；否则返回false。
     */
    @AssertFalse(message = "maybeA和maybeB不能同时为空，至少需要提供一个值。")
    private boolean oneFieldHasToExists() {
        // 当maybeA和maybeB都为null时，我们认为这是无效状态，返回true
        return maybeA == null && maybeB == null;
    }

    // 可以在此处添加main方法或其他测试代码来验证
    public static void main(String[] args) {
        // 示例1: A和B都存在 - 应该通过校验
        Example example1 = Example.builder().maybeA("ValueA").maybeB("ValueB").build();
        System.out.println("Example 1: " + example1.getMaybeA() + ", " + example1.getMaybeB());
        // 实际应用中，会通过Validator实例来校验

        // 示例2: 只有A存在 - 应该通过校验
        Example example2 = Example.builder().maybeA("ValueA").build();
        System.out.println("Example 2: " + example2.getMaybeA() + ", " + example2.getMaybeB());

        // 示例3: 只有B存在 - 应该通过校验
        Example example3 = Example.builder().maybeB("ValueB").build();
        System.out.println("Example 3: " + example3.getMaybeA() + ", " + example3.getMaybeB());

        // 示例4: A和B都不存在 - 应该触发校验失败
        Example example4 = Example.builder().build();
        System.out.println("Example 4: " + example4.getMaybeA() + ", " + example4.getMaybeB());
    }
}

<!-- Maven 依赖示例 -->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-validation</artifactId>
</dependency>
<!-- 或直接引入JSR 303 API和实现 -->
<dependency>
    <groupId>javax.validation</groupId>
    <artifactId>validation-api</artifactId>
    <version>2.0.1.Final</version> <!-- 或更高版本 -->
</dependency>
<dependency>
    <groupId>org.hibernate.validator</groupId>
    <artifactId>hibernate-validator</artifactId>
    <version>6.0.13.Final</version> <!-- 或更高版本 -->
</dependency>

import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RestController;
import javax.validation.Valid;

@RestController
public class ExampleController {

    @PostMapping("/examples")
    public String createExample(@Valid @RequestBody Example example) {
        // 如果example对象校验通过，则执行业务逻辑
        return "Example created successfully: A=" + example.getMaybeA() + ", B=" + example.getMaybeB();
    }
}