Java Feign分页API通用抽象与函数式优化实践

public interface SingleParamPagingApi<T> {
    ResponseEntity<IVDPagedResponseOf<T>> callFeignApi(String arg, int page, int size) throws RuntimeException;
}

public static class SingleParamPageableCall<T> implements PagedCall<T> {
    SingleParamPagingApi<T> fun;
    String param;

    public SingleParamPageableCall(SingleParamPagingApi<T> fun, String param) {
        this.fun = fun;
        this.param = param;
    }

    @Override
    public BaseFeignResult<T> call(int p, int s) {
        BaseFeignResult.BaseFeignResultBuilder<T> builder = BaseFeignResult.builder();
        try {
            builder.resp(fun.callFeignApi(param, p, s));
        } catch (RuntimeException e) {
            builder.excp(e);
        }
        return builder.build();
    }
}

// 核心分页调用逻辑
public <T> List<BaseFeignResult<T>> drainFeignPageableCall(PagedCall<T> feignCall) {
    // ... 分页获取逻辑 ...
}

// 具有一个固定参数的API接口
public interface PagingApi1<T, A0> {
    ResponseEntity<IVDPagedResponseOf<T>> callFeignApi(A0 arg0, int page, int size) throws RuntimeException;
}

// 具有两个固定参数的API接口
public interface PagingApi2<T, A0, A1> {
    ResponseEntity<IVDPagedResponseOf<T>> callFeignApi(A0 arg0, A1 arg1, int page, int size) throws RuntimeException;
}

// 可以根据需要定义更多 PagingApiN 接口

public interface PagingApi<T> {

    // 静态工厂方法：用于绑定一个固定参数的API
    static <T, A0> PagingApi<T> of(PagingApi1<T, A0> api, A0 arg0) {
        // 返回一个lambda表达式，它捕获了arg0，并调用原始API
        return (p, s) -> api.callFeignApi(arg0, p, s);
    }

    // 静态工厂方法：用于绑定两个固定参数的API
    static <T, A0, A1> PagingApi<T> of(PagingApi2<T, A0, A1> api, A0 arg0, A1 arg1) {
        // 返回一个lambda表达式，它捕获了arg0和arg1，并调用原始API
        return (p, s) -> api.callFeignApi(arg0, arg1, p, s);
    }

    // 此方法是通用PagingApi的实际调用签名，只接受分页参数
    ResponseEntity<IVDPagedResponseOf<T>> callFeignApi(int page, int size) throws RuntimeException;
}

public static class PageableCall<T> implements PagedCall<T> {
    PagingApi<T> fun; // 现在只依赖于通用的 PagingApi

    public PageableCall(PagingApi<T> fun) {
        this.fun = fun;
    }

    @Override
    public BaseFeignResult<T> call(int p, int s) {
        BaseFeignResult.BaseFeignResultBuilder<T> builder = BaseFeignResult.builder();
        try {
            builder.resp(fun.callFeignApi(p, s)); // 直接调用 PagingApi 的方法
        } catch (RuntimeException e) {
            builder.excp(e);
        }
        return builder.build();
    }
}

// 假设 ordersFeignClient::getOrdersBySampleIds 是一个接受 (String, int, int) 参数的方法
drainFeignPageableCall(
    new PageableCall<GetOrderInfoDto>(
        PagingApi.of(ordersFeignClient::getOrdersBySampleIds, "34596") // 使用静态of方法绑定参数
    )
);

// 如果有一个Feign方法是 (String, String, int, int)
// drainFeignPageableCall(
//     new PageableCall<AnotherInfoDto>(
//         PagingApi.of(anotherFeignClient::getAnotherInfo, "param1Value", "param2Value")
//     )
// );

// 合并后的接口
public interface UnifiedPagedCaller<T> {
    static <T, A0> UnifiedPagedCaller<T> of(PagingApi1<T, A0> api, A0 arg0) {
        return (p, s) -> { /* 包装调用逻辑 */ };
    }
    // ... 其他 of 方法 ...

    BaseFeignResult<T> call(int p, int s); // 封装了 ResponseEntity 和异常处理
}

public <T> List<BaseFeignResult<T>> drainFeignPageableCall(PagedCall<T> feignCall) {
    List<BaseFeignResult<T>> allResults = new ArrayList<>();
    int page = 0;
    int pageSize = 10; // 假设固定页面大小

    while (true) {
        BaseFeignResult<T> currentPageResult = feignCall.call(page, pageSize);
        allResults.add(currentPageResult);

        // 检查是否还有下一页数据
        // 这里需要根据 IVDPagedResponseOf<T> 的具体结构判断
        // 假设 IVDPagedResponseOf 有一个 getTotalElements() 和 getContent() 方法
        if (currentPageResult.getResp() == null || currentPageResult.getResp().getBody() == null) {
            // 如果响应为空，可能发生错误或数据结束
            break;
        }

        IVDPagedResponseOf<T> pagedResponse = currentPageResult.getResp().getBody();
        if (pagedResponse.getContent() == null || pagedResponse.getContent().size() < pageSize) {
            // 如果当前页数据量小于页面大小，说明是最后一页
            break;
        }

        page++;
    }
    return allResults;
}