Java 發送multipart/form-data帶有Json文件的Post請求

在實際工作中有一個這樣的需求，前端需要上傳一個圖片文件到第三方的服務服務中，但是前端又不能直接調用第三方的接口上傳，只能通過我們服務作為中間服務上傳圖片到第三方服務中，即前端調我們的接口，我們再調第三方的接口進行上傳。

使用postman工具發送multipart/form-data帶有Json文件的Post請求，文件內容其實就是json字符串，這種請求通過postman發送，他給你處理，但是你需要做接口化測試就得偶用代碼來實現，不是使用他的工具，就需要你自己寫代碼了

搭建步驟

1.導入依賴

<dependency>
    <groupId>org.apache.httpcomponents</groupId>
    <artifactId>httpclient</artifactId>
    <version>4.5.3</version>
</dependency>
<dependency>
    <groupId>org.apache.httpcomponents</groupId>
    <artifactId>httpmime</artifactId>
    <version>4.3.6</version>
</dependency>

2.請求代碼處理

package com.sean.formdata.controller;

import lombok.extern.slf4j.Slf4j;
import org.apache.http.HttpEntity;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.ContentType;
import org.apache.http.entity.mime.MultipartEntityBuilder;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.multipart.MultipartFile;

import java.io.IOException;
import java.nio.charset.Charset;

/**
 * @author : sean
 * @version V1.0
 * @Project: formdata
 * @Package com.sean.formdata.controller
 * @date Date : 2021年09月28日 21:29
 * @Description:
 */
@RestController
@Slf4j
public class FormDataController {


    @PostMapping("/formdata")
    public void formData(@RequestBody MultipartFile file,String url)
    {
        try {
              MultipartEntityBuilder builder = MultipartEntityBuilder.create();
              //設置編碼格式
              builder.setCharset(Charset.forName("UTF8"));
              //設置請求體的參數
              builder.addTextBody("username","zhangsan");
              builder.addTextBody("password","lisi");
              builder.addTextBody("age","18");
              builder.addTextBody("email","[e-mail]");
              //把文件放到請求體中
              builder.addBinaryBody("file",file.getInputStream(), ContentType.MULTIPART_FORM_DATA,file.getOriginalFilename());
              //構建請求實體
              HttpEntity entity = builder.build();

            //  創建Post方式請求
            HttpPost httpPost = new HttpPost(url);
            httpPost.setEntity(entity);

            CloseableHttpClient httpClient = HttpClients.createDefault();
            //發送請求
            CloseableHttpResponse httpResponse = httpClient.execute(httpPost);

            //狀態碼
            int statusCode = httpResponse.getStatusLine().getStatusCode();
            //msg
            String reasonPhrase = httpResponse.getStatusLine().getReasonPhrase();
            //data
            String responseBody = EntityUtils.toString(httpResponse.getEntity(),"UTF-8");

        } catch (IOException e) {
            e.printStackTrace();
        }

    }
}

3.遇到的問題

在訪問第三方提供的接口時，有可能是http或https請求，如果是http請求直接使用代碼是沒有問題的，如果是https請求的話就不行，需要提供CA證書，但是又沒有證書的情況下，就需要繞過Https的證書認證。

/**
     * 獲取https連接（不驗證證書）
     *
     * @return
     */
    private static CloseableHttpClient getHttpsClient() {
        RegistryBuilder<ConnectionSocketFactory> registryBuilder = RegistryBuilder.<ConnectionSocketFactory>create();
        ConnectionSocketFactory plainSF = new PlainConnectionSocketFactory();
        registryBuilder.register("http", plainSF);
        // 指定信任密鑰存儲對象和連接套接字工廠
        try {
            KeyStore trustStore = KeyStore.getInstance(KeyStore.getDefaultType());
            // 信任任何鏈接
            TrustStrategy anyTrustStrategy = new TrustStrategy() {

                @Override
                public boolean isTrusted(java.security.cert.X509Certificate[] arg0, String arg1) throws java.security.cert.CertificateException {
                    // TODO Auto-generated method stub
                    return true;
                }
            };
            SSLContext sslContext = SSLContexts.custom().useTLS().loadTrustMaterial(trustStore, anyTrustStrategy).build();
            LayeredConnectionSocketFactory sslSF = new SSLConnectionSocketFactory(sslContext, SSLConnectionSocketFactory.ALLOW_ALL_HOSTNAME_VERIFIER);
            registryBuilder.register("https", sslSF);
        } catch (KeyStoreException e) {
            throw new RuntimeException(e);
        } catch (KeyManagementException e) {
            throw new RuntimeException(e);
        } catch (NoSuchAlgorithmException e) {
            throw new RuntimeException(e);
        }
        Registry<ConnectionSocketFactory> registry = registryBuilder.build();
        // 設置連接管理器
        PoolingHttpClientConnectionManager connManager = new PoolingHttpClientConnectionManager(registry);
        // 構建客戶端
        return HttpClientBuilder.create().setConnectionManager(connManager).build();
    }