Java httpclient請(qǐng)求form-data格式并設(shè)置boundary代碼實(shí)現(xiàn)方法

更新時(shí)間：2025年01月22日 11:22:42 作者：Mr.Java.

在 Java 開(kāi)發(fā)中,經(jīng)常會(huì)遇到需要使用 httpclient 發(fā)送 form-data 格式請(qǐng)求的場(chǎng)景,本文將詳細(xì)介紹如何正確地實(shí)現(xiàn)這一操作,包括數(shù)據(jù)格式示例、常見(jiàn)報(bào)錯(cuò)及解決方法,本文通過(guò)實(shí)例代碼詳解講解,感興趣的朋友一起看看吧

在 Java 開(kāi)發(fā)中，經(jīng)常會(huì)遇到需要使用 httpclient 發(fā)送 form-data 格式請(qǐng)求的場(chǎng)景。本文將詳細(xì)介紹如何正確地實(shí)現(xiàn)這一操作，包括數(shù)據(jù)格式示例、常見(jiàn)報(bào)錯(cuò)及解決方法，以及完整的 Java 代碼實(shí)現(xiàn)。

form-data 數(shù)據(jù)請(qǐng)求格式樣例

我們先看下 form-data 數(shù)據(jù)的格式是長(zhǎng)什么樣的。
例如要傳輸 form-data 的鍵值對(duì)是：
a: aaa
b: bbb
請(qǐng)求的boundary設(shè)置如下：
addHeader(“Content-type”, “multipart/form-data;boundary=----12345”)

實(shí)際請(qǐng)求格式會(huì)加上boundary，請(qǐng)求示例如下

----12345
Content-Disposition: form-data; name="a"
aaa
----12345
Content-Disposition: form-data; name="b"
bbb

postman自動(dòng)生成的 boundary 如下：

Accept-Encoding: gzip, deflate, br
Connection: keep-alive
Content-Type: multipart/form-data; boundary=--------------------------477613155954799910398847

報(bào)錯(cuò)信息: MissingServletRequestParameterException解決方法

org.springframework.web.bind.MissingServletRequestParameterException

請(qǐng)求Headers中的Content-Type類型不對(duì)
addHeader(“Content-Type”, “application/json; charset=UTF-8”);
將Json換成multipart/form-data
addHeader(“Content-type”, “multipart/form-data; charset=UTF-8; boundary=” + new UUIDGenerator().next());

報(bào)錯(cuò)信息: no multipart boundary was found 解決方法

org.apache.tomcat.util.http.fileupload.FileUploadException: the request was rejected because no multipart boundary was found

這個(gè)報(bào)錯(cuò)是沒(méi)有設(shè)置邊界分隔符
解決方法：

headers中添加boundary

addHeader("Content-type", "multipart/form-data;boundary=" + boundary)

multipart/form-data 請(qǐng)求參數(shù)添加boundary

MultipartEntityBuilder multipartEntityBuilder = MultipartEntityBuilder.create()
        .setCharset(StandardCharsets.UTF_8)
        // [重要]:設(shè)置 setBoundary 邊界分隔符
        .setBoundary(boundary);

Java代碼實(shí)現(xiàn)

【錯(cuò)誤】使用 UrlEncodedFormEntity 、BasicNameValuePair 請(qǐng)求失?。╡rror）

public static JSONObject test(String URL) throws IOException {
    RequestConfig requestConfig = RequestConfig.custom().build();
    try (CloseableHttpClient httpClient = HttpClientBuilder.create().build()) {
        HttpPost post = new HttpPost(URL);
        List<NameValuePair> list = new ArrayList<>();
        BasicNameValuePair pair1 = new BasicNameValuePair("a", "aaa");
        BasicNameValuePair pair2 = new BasicNameValuePair("b", "bbb");
        list.add(pair1);
        list.add(pair2);
        UrlEncodedFormEntity urlEncodedFormEntity = new UrlEncodedFormEntity(list,"UTF-8");
        post.setEntity(urlEncodedFormEntity);
        String boundary = new UUIDGenerator().next();
        // 設(shè)置請(qǐng)求格式 multipart/form-data
        post.addHeader("Content-type", "multipart/form-data;boundary=" + boundary);
        post.addHeader("Accept", "*/*");
        // UTF-8 解決中文亂碼
        post.addHeader("Accept-Encoding", "UTF-8");
        post.addHeader("User-Agent", " Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/123.0.0.0 Safari/537.36");
        // 發(fā)送 post 請(qǐng)求
        HttpResponse response = httpClient.execute(post);
        ...省略代碼
}

上面的代碼使用了 UrlEncodedFormEntity,BasicNameValuePair 去設(shè)置請(qǐng)求格式 multipart/form-data，雖然在 Content-type中設(shè)置了 boundary，請(qǐng)求還是報(bào)請(qǐng)求參數(shù)錯(cuò)誤：MissingServletRequestParameterException
是因?yàn)椴](méi)有在 multipart/form-data 的請(qǐng)求數(shù)據(jù)前后設(shè)置分割邊界符

【正確】使用 MultipartEntityBuilder 構(gòu)造 boundary

要使用MultipartEntityBuilder，先引入maven

<dependency>
    <groupId>org.apache.httpcomponents</groupId>
    <artifactId>httpclient</artifactId>
    <version>4.5</version>
</dependency>
<dependency>
    <groupId>org.apache.httpcomponents</groupId>
    <artifactId>httpmime</artifactId>
    <version>4.5</version>
</dependency>

java用httpclient（apache）完整的純文本form-data請(qǐng)求實(shí)現(xiàn)如下：

public enum Test {
    ;
    private static final Logger logger = LoggerFactory.getLogger(Test.class);
    /**
     * setConnectTimeout: 從客戶端到url建立連接的超時(shí)時(shí)間
     */
    private static final int CONNECT_TIMEOUT = 30 * 1000;
    /**
     * setSocketTimeout: 連接上一個(gè)url后，獲取response的返回等待時(shí)間
     */
    private static final int SOCKET_TIMEOUT = 3600 * 1000;
    public static JSONObject postHttpFormDataPair(String URL, JSONObject requestBodyJson, Map<String, String> headersMap, String... saveRespHeaderName) {
        RequestConfig requestConfig = RequestConfig.custom()
                .setConnectTimeout(CONNECT_TIMEOUT)
                .setSocketTimeout(SOCKET_TIMEOUT)
                .setCookieSpec(CookieSpecs.DEFAULT)
                .build();
        CookieStore cookieStore = new BasicCookieStore();
        // 默認(rèn)是 CloseableHttpClient httpClient = HttpClientBuilder.create().build();
        try (CloseableHttpClient httpClient = createSSLClientDefaultBuilder()
                .setDefaultRequestConfig(requestConfig)
                .setDefaultCookieStore(cookieStore)
                .build()) {
            HttpPost post = new HttpPost(URL);
            // [重要]:生成邊界分隔符 boundary
            String boundary = new UUIDGenerator().next();
            // [重要]:設(shè)置請(qǐng)求格式 multipart/form-data
            post.addHeader("Content-type", "multipart/form-data; charset=UTF-8; boundary=" + boundary);
            post.addHeader("Accept", "*/*");
            post.addHeader("Accept-Encoding", "UTF-8");
            post.addHeader("User-Agent", " Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/123.0.0.0 Safari/537.36");
            if (!CollectionUtils.isEmpty(headersMap)) {
                for (Map.Entry<String, String> entry : headersMap.entrySet()) {
                    post.addHeader(entry.getKey(), entry.getValue());
                }
            }
            // 構(gòu)造 formdata 請(qǐng)求數(shù)據(jù)
            MultipartEntityBuilder multipartEntityBuilder = MultipartEntityBuilder.create()
                    .setCharset(StandardCharsets.UTF_8)
                    // [重要]:設(shè)置 setBoundary 邊界分隔符
                    .setBoundary(boundary);
            multipartEntityBuilder.addTextBody("a", "aaa");
            multipartEntityBuilder.addTextBody("b", "bbb");
            HttpEntity postFormDataBody = multipartEntityBuilder.build();
            // 請(qǐng)求參數(shù)
            post.setEntity(postFormDataBody);
            // 發(fā)送 post 請(qǐng)求
            HttpResponse response = httpClient.execute(post);
            if (response == null) {
                throw new RuntimeException("response is null");
            } else if (response.getStatusLine().getStatusCode() == HttpStatus.SC_OK) {
                return getResponseJsonObject(response, saveRespHeaderName);
            } else {
                logger.warn("response status is not 200");
                return getResponseJsonObject(response, saveRespHeaderName);
            }
        } catch (Exception ex) {
            logger.error("error:", ex);
            throw new RuntimeException("系統(tǒng)異常");
        }
    }
    @NotNull
    private static JSONObject getResponseJsonObject(HttpResponse response, String[] saveRespHeaderName) throws IOException {
        InputStream in = response.getEntity().getContent();
        BufferedReader reader = new BufferedReader(new InputStreamReader(in));
        String lines;
        StringBuilder responseMsg = new StringBuilder("");
        while ((lines = reader.readLine()) != null) {
            lines = new String(lines.getBytes(), StandardCharsets.UTF_8);
            responseMsg.append(lines);
        }
        reader.close();
        in.close();
        JSONObject jsonObject = new JSONObject();
        jsonObject.put("message", responseMsg.toString());
        // save header
        for (String name : saveRespHeaderName) {
            jsonObject.put(name, response.getHeaders(name));
        }
        return jsonObject;
    }
    /**
     * 繞過(guò)https證書校驗(yàn)
     */
    public static HttpClientBuilder createSSLClientDefaultBuilder() {
        HttpClientBuilder httpClientBuilder = null;
        try {
            SSLContextBuilder builder = new SSLContextBuilder();
            // 實(shí)現(xiàn)該接口，證書受信任的X509證書校驗(yàn)為true
            builder.loadTrustMaterial(null, (chain, authType) -> true);
            // 創(chuàng)建HttpsURLConnection對(duì)象，并設(shè)置其SSLSocketFactory對(duì)象
            SSLConnectionSocketFactory socketFactory = new SSLConnectionSocketFactory(builder.build(), new String[]{"TLSv1.2"}, null, NoopHostnameVerifier.INSTANCE);
            //  HttpsURLConnection對(duì)象就可以正常連接HTTPS了，無(wú)論其證書是否經(jīng)權(quán)威機(jī)構(gòu)的驗(yàn)證，只要實(shí)現(xiàn)了接口X509TrustManager的類MyX509TrustManager信任該證書。
            httpClientBuilder = HttpClients.custom().setSSLSocketFactory(socketFactory);
        } catch (Exception e) {
            e.printStackTrace();
            throw new RuntimeException("系統(tǒng)異常");
        }
        return httpClientBuilder;
    }
}

總結(jié)

想要代碼實(shí)現(xiàn) form-data格式的請(qǐng)求要注意下面2點(diǎn)：

設(shè)置 boundary 邊界分隔符

設(shè)置 Content-type

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