给出以下代码。
@Getter
@Builder(builderClassName = "Builder", buildMethodName = "build")
public final class BusinessEvent implements BusinessPayload {
private String action, duration, outcome, provider, trackId, sequence;
@lombok.Builder.Default private Optional<String> brand, vin, externalTrackId, code = Optional.empty();
@lombok.Builder.Default private Optional<BusinessEventError> eventError = Optional.empty();
static class Builder {
BusinessEvent build() throws MissingRequiredValueException {
// Custom validation
return new BusinessEvent(action, duration, outcome, provider, trackId, sequence, brand, vin, externalTrackId, code, eventError);
}
}
}
我收到错误
java: non-static variable eventError cannot be referenced from a static context
在这种情况下,lombok 无法正确处理可选值?我在所有 build 者身上都看到了同样的问题。这不会被 intellij 插件显示为问题,但仅在我尝试构建时显示为问题。
我知道您不应该使用可选值作为字段值,但在这种情况下,它使 API 更加清晰,并且构建器无论如何都不会被序列化,我们为此提供了 DTO。
最佳答案
总结一下你想做的事情:
- 您想要一个由 lombok 生成的构建器
- 您希望使用
@Default
在构建器中分配默认值 - 您希望在构建方法中进行自定义验证
这似乎不起作用。既不适用于Optional,也不适用于其他对象。似乎是 lombok 的限制。
IntelliJ 没有将其识别为错误这一事实并不意味着它应该可以工作。但是你的编译失败了。这是一个现实问题。
考虑以下代码,不带 @lombok.Builder.Default
注释:
@Getter
@Builder(builderClassName = "Builder", buildMethodName = "build")
public final class BusinessEvent {
private String action, duration, outcome, provider, trackId, sequence;
private Optional<String> brand, vin, externalTrackId, code = Optional.empty();
private Optional<Object> eventError = Optional.empty();
static class Builder {
BusinessEvent build() {
if (brand == null) {
throw new RuntimeException("brand not set");
}
// Custom validation
return new BusinessEvent(action, duration, outcome, provider, trackId, sequence, brand, vin, externalTrackId, code, eventError);
}
}
public static void main(String[] args) {
BusinessEvent eventWithBrand = BusinessEvent.builder().brand(Optional.of("brand")).build();
// will throw exception
BusinessEvent event = BusinessEvent.builder().build();
}
}
关于java - 可选的 Lombok 自定义构建方法表示无法引用非静态变量,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/59191793/