Java中利用继承和多态实现通用参数校验方法

// 定义创建对象的请求记录
public record CreateObjectRequest (
    CustomObjectA a,
    CustomObjectB b,
    CustomObjectC c
) {}

// 定义更新对象的请求记录
public record UpdateObjectRequest (
    CustomObjectA a,
    CustomObjectB b
) {}

// 针对不同请求类型编写独立的校验方法
public class RequestValidator {
    public void validateRequest(CreateObjectRequest createObjectRequest) {
        // 冗长的校验逻辑，例如检查字段a、b是否为空
        if (createObjectRequest.a() == null) {
            throw new IllegalArgumentException("字段 a 不能为空");
        }
        if (createObjectRequest.b() == null) {
            throw new IllegalArgumentException("字段 b 不能为空");
        }
        if (createObjectRequest.c() == null) {
            throw new IllegalArgumentException("字段 c 不能为空");
        }
        // ... 更多校验
    }

    public void validateRequest(UpdateObjectRequest updateObjectRequest) {
        // 几乎相同的校验逻辑，例如检查字段a、b是否为空
        if (updateObjectRequest.a() == null) {
            throw new IllegalArgumentException("字段 a 不能为空");
        }
        if (updateObjectRequest.b() == null) {
            throw new IllegalArgumentException("字段 b 不能为空");
        }
        // ... 更多校验
    }
}

// 假设 CustomObjectA, CustomObjectB, CustomObjectC 是已定义的类型
class CustomObjectA {}
class CustomObjectB {}
class CustomObjectC {}

// 定义抽象父类，包含所有请求对象共有的字段
public abstract class ObjectRequest {
    protected CustomObjectA a;
    protected CustomObjectB b;

    public ObjectRequest(CustomObjectA a, CustomObjectB b) {
        this.a = a;
        this.b = b;
    }

    // 提供公共字段的访问器方法
    public CustomObjectA a() { return a; }
    public CustomObjectB b() { return b; }
}

// CreateObjectRequest 继承 ObjectRequest，并添加特有字段
public class CreateObjectRequest extends ObjectRequest {
    private CustomObjectC c;

    public CreateObjectRequest(CustomObjectA a, CustomObjectB b, CustomObjectC c) {
        super(a, b); // 调用父类构造函数初始化公共字段
        this.c = c;
    }

    public CustomObjectC c() { return c; }
}

// UpdateObjectRequest 继承 ObjectRequest，只使用公共字段
public class UpdateObjectRequest extends ObjectRequest {
    public UpdateObjectRequest(CustomObjectA a, CustomObjectB b) {
        super(a, b); // 调用父类构造函数初始化公共字段
    }
}

public class RequestValidator {
    public void validateRequest(ObjectRequest objectRequest) {
        // 校验公共字段
        if (objectRequest.a() == null) {
            throw new IllegalArgumentException("公共字段 a 不能为空");
        }
        if (objectRequest.b() == null) {
            throw new IllegalArgumentException("公共字段 b 不能为空");
        }

        // 如果需要处理子类特有字段，可以使用 instanceof 运算符进行类型检查和向下转型
        if (objectRequest instanceof CreateObjectRequest createRequest) {
            if (createRequest.c() == null) {
                throw new IllegalArgumentException("CreateObjectRequest 特有字段 c 不能为空");
            }
        }
        // 可以在这里添加更多通用的校验逻辑
        System.out.println("请求校验成功！");
    }

    public static void main(String[] args) {
        RequestValidator validator = new RequestValidator();

        // 测试 CreateObjectRequest
        CreateObjectRequest createReq1 = new CreateObjectRequest(new CustomObjectA(), new CustomObjectB(), new CustomObjectC());
        validator.validateRequest(createReq1); // 校验成功

        // 测试 CreateObjectRequest 字段缺失
        try {
            CreateObjectRequest createReq2 = new CreateObjectRequest(null, new CustomObjectB(), new CustomObjectC());
            validator.validateRequest(createReq2);
        } catch (IllegalArgumentException e) {
            System.out.println("校验失败: " + e.getMessage()); // 输出: 公共字段 a 不能为空
        }

        // 测试 UpdateObjectRequest
        UpdateObjectRequest updateReq1 = new UpdateObjectRequest(new CustomObjectA(), new CustomObjectB());
        validator.validateRequest(updateReq1); // 校验成功

        // 测试 UpdateObjectRequest 字段缺失
        try {
            UpdateObjectRequest updateReq2 = new UpdateObjectRequest(new CustomObjectA(), null);
            validator.validateRequest(updateReq2);
        } catch (IllegalArgumentException e) {
            System.out.println("校验失败: " + e.getMessage()); // 输出: 公共字段 b 不能为空
        }
    }
}