如何Mock Apache HttpClient 5.x中的CloseableHttpResponse？

针对你遇到的CloseableHttpResponse无法直接实例化（且不想依赖Mockito final mock机制）的问题，有两个更规范、简便的方案：

方案一：使用官方测试工具类 #

Apache HttpClient 5.x专门提供了测试专用的工具类CloseableHttpResponses（位于org.apache.hc.client5.testing包下），可以直接生成符合要求的CloseableHttpResponse实例，完全官方支持，无mock风险。

操作步骤： #

1. 先在测试依赖中引入httpclient5-testing模块：

<dependency>
    <groupId>org.apache.httpcomponents.client5</groupId>
    <artifactId>httpclient5-testing</artifactId>
    <version>你的HttpClient 5.x版本号</version>
    <scope>test</scope>
</dependency>

2. 在测试代码中直接调用静态方法生成响应：

// 生成200 OK的空响应
CloseableHttpResponse okResponse = CloseableHttpResponses.create(HttpStatus.SC_OK);

// 生成带JSON响应实体的200响应
String responseBody = "{\"data\": \"test\"}";
HttpEntity entity = new StringEntity(responseBody, ContentType.APPLICATION_JSON);
CloseableHttpResponse responseWithBody = CloseableHttpResponses.create(HttpStatus.SC_OK, entity);

方案二：手动实现CloseableHttpResponse接口 #

由于CloseableHttpResponse本质是接口，你可以编写极简实现类，只覆盖测试需要用到的方法，其他方法留空或抛出不支持异常即可，完全可控且无额外依赖。

示例实现：

import org.apache.hc.core5.http.*;
import org.apache.hc.core5.http.io.entity.HttpEntity;
import java.io.Closeable;
import java.io.IOException;

public class MockHttpResponse implements CloseableHttpResponse {
    private final int statusCode;
    private final HttpEntity entity;

    public MockHttpResponse(int statusCode, HttpEntity entity) {
        this.statusCode = statusCode;
        this.entity = entity;
    }

    @Override
    public StatusLine getStatusLine() {
        return new BasicStatusLine(HttpVersion.HTTP_1_1, statusCode, "Success");
    }

    @Override
    public HttpEntity getEntity() {
        return entity;
    }

    @Override
    public void close() throws IOException {
        // 测试环境无需实际关闭资源，空实现即可
    }

    // 以下为其他接口方法的极简实现，按需调整
    @Override
    public ProtocolVersion getProtocolVersion() {
        return HttpVersion.HTTP_1_1;
    }

    @Override
    public boolean containsHeader(String name) {
        return false;
    }

    @Override
    public Header[] getHeaders(String name) {
        return new Header[0];
    }

    @Override
    public Header getFirstHeader(String name) {
        return null;
    }

    @Override
    public Header getLastHeader(String name) {
        return null;
    }

    @Override
    public Header[] getAllHeaders() {
        return new Header[0];
    }

    @Override
    public void addHeader(Header header) {}

    @Override
    public void addHeader(String name, String value) {}

    @Override
    public void setHeader(Header header) {}

    @Override
    public void setHeader(String name, String value) {}

    @Override
    public void setHeaders(Header[] headers) {}

    @Override
    public void removeHeader(Header header) {}

    @Override
    public void removeHeaders(String name) {}

    @Override
    public HttpResponse setStatusLine(StatusLine statusLine) {
        throw new UnsupportedOperationException();
    }

    @Override
    public HttpResponse setStatusLine(ProtocolVersion ver, int code) {
        throw new UnsupportedOperationException();
    }

    @Override
    public HttpResponse setStatusLine(ProtocolVersion ver, int code, String reason) {
        throw new UnsupportedOperationException();
    }

    @Override
    public HttpResponse setStatusCode(int code) throws IllegalStateException {
        throw new UnsupportedOperationException();
    }

    @Override
    public HttpResponse setReasonPhrase(String reason) throws IllegalStateException {
        throw new UnsupportedOperationException();
    }

    @Override
    public HttpResponse setEntity(HttpEntity entity) {
        throw new UnsupportedOperationException();
    }

    @Override
    public HttpResponse addHeader(HeaderIterator iterator) {
        throw new UnsupportedOperationException();
    }

    @Override
    public HttpResponse setHeader(HeaderIterator iterator) {
        throw new UnsupportedOperationException();
    }
}

测试时直接实例化这个类：

HttpEntity testEntity = new StringEntity("test content", ContentType.TEXT_PLAIN);
CloseableHttpResponse mockResponse = new MockHttpResponse(HttpStatus.SC_OK, testEntity);

这两个方案都规避了Mockito final mock的风险，且符合HttpClient的设计规范，是更稳妥的选择。

内容的提问来源于stack exchange，提问作者dinhokz