前言#

刷视频看到一种使用泛型约束，在 Request 中绑定 Response，从而简洁优雅地实现灵活扩展请求参数和返回参数，这种方式在 SDK 源码中很常见，比较简单实用，觉得有点意思，写个 demo 分享一下

Demo#

Response#

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@Getter
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@Setter
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public abstract class BaseResponse {
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    private int statusCode;
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}

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@Getter
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@Setter
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public class Example1Response extends BaseResponse {
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    private String response1;
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}
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@Getter
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@Setter
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public class Example2Response extends BaseResponse {
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    private String response2;
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}

Request#

定义 BaseRequest，使用泛型指定返回类型为 BaseResponse 的子类

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@Getter
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@Setter
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public abstract class BaseRequest<T extends BaseResponse> {
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    private String code;
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    public abstract Class<T> getResponseType();
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}

Request 指定返回的具体 Response 类型

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@Getter
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@Setter
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public class Example1Request extends BaseRequest<Example1Response> {
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    private String example1;
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    @Override
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    public Class<Example1Response> getResponseType() {
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        return Example1Response.class;
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    }
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}
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@Getter
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@Setter
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public class Example2Request extends BaseRequest<Example2Response> {
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    private String example2;
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    @Override
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    public Class<Example2Response> getResponseType() {
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        return Example2Response.class;
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    }
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}

Client#

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public class ExampleClient {
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    private String postRequest(String param) {
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        try (HttpResponse response = HttpUtil.createPost("https://api.demo.com/api").body(param).execute()) {
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            if (response.isOk()) {
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                return response.body();
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            } else {
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                System.err.println("HTTP请求失败，状态码: " + response.getStatus());
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                return null;
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            }
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        } catch (Exception e) {
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            System.err.println("发送HTTP请求时发生异常: " + e.getMessage());
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            return null;
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        }
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    }
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    public <T extends BaseResponse> T execute(BaseRequest<T> request) {
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        String result = postRequest(JSONUtil.toJsonStr(request));
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        // 根据 request 绑定的响应类型转换 result
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        return JSONUtil.toBean(result, request.getResponseType());
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    }
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}

Example#

在使用 execute 方法的时候，根据请求参数的不同，自动返回对应的响应类型

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public static void main(String[] args) {
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    ExampleClient exampleClient = new ExampleClient();
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    Example1Request example1Request = new Example1Request();
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    Example1Response execute1 = exampleClient.execute(example1Request);
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    Example2Request example2Request = new Example2Request();
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    Example2Response execute2 = exampleClient.execute(example2Request);
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}