HttpClient上传下载文件

Maven依赖

<dependency><groupId>org.apache.httpcomponents</groupId><artifactId>httpclient</artifactId><version>4.5.1</version>
</dependency>
<dependency><groupId>org.apache.httpcomponents</groupId><artifactId>httpmime</artifactId><version>4.5.1</version>
</dependency>
<dependency><groupId>eu.medsea.mimeutil</groupId><artifactId>mime-util</artifactId><version>2.1.3</version>
</dependency>
<dependency><groupId>javax</groupId><artifactId>javaee-api</artifactId><version>7.0</version>
</dependency>

上传文件

/*** 上传文件* * @param url*            上传路径* @param file*            文件路径* @param stringBody*            附带的文本信息* @return 响应结果*/
public static String upload(String url, String file, String stringBody) {String result = "";CloseableHttpClient httpclient = null;CloseableHttpResponse response = null;HttpEntity resEntity = null;try {httpclient = buildHttpClient();HttpPost httppost = new HttpPost(url);// 把文件转换成流对象FileBodyFileBody bin = new FileBody(new File(file));StringBody comment = new StringBody(stringBody, ContentType.create("text/plain", Consts.UTF_8));// 以浏览器兼容模式运行，防止文件名乱码。HttpEntity reqEntity = MultipartEntityBuilder.create().setMode(HttpMultipartMode.BROWSER_COMPATIBLE).addPart("bin", bin).addPart("comment", comment).setCharset(Consts.UTF_8).build();httppost.setEntity(reqEntity);log.info("executing request " + httppost.getRequestLine());response = httpclient.execute(httppost);log.info(response.getStatusLine());resEntity = response.getEntity();if (resEntity != null) {log.info("Response content length: "+ resEntity.getContentLength());result = EntityUtils.toString(resEntity, Consts.UTF_8);}} catch (Exception e) {log.error("executing request " + url + " occursing some error.");log.error(e);} finally {try {EntityUtils.consume(resEntity);response.close();httpclient.close();} catch (IOException e) {log.error(e);}}return result;
}

下载文件

/*** 下载文件* @param url 下载url* @param fileName 保存的文件名（可以为null）*/
public static void download(String url, String fileName) {String path = "G:/download/";CloseableHttpClient httpclient = null;CloseableHttpResponse response = null;HttpEntity entity = null;try {httpclient = buildHttpClient();HttpGet httpget = new HttpGet(url);response = httpclient.execute(httpget);entity = response.getEntity();// 下载if (entity.isStreaming()) {String destFileName = "data";if (!isBlank(fileName)) {destFileName = fileName;} else if (response.containsHeader("Content-Disposition")) {String dstStr = response.getLastHeader("Content-Disposition").getValue();dstStr = decodeHeader(dstStr);//使用正则截取Pattern p = Pattern.compile("filename=\"?(.+?)\"?$");Matcher m = p.matcher(dstStr);if (m.find()) {destFileName = m.group(1);}} else {destFileName = url.substring(url.lastIndexOf("/") + 1);}log.info("downloading file: " + destFileName);FileOutputStream fos = null;try {fos = new FileOutputStream(path + destFileName);entity.writeTo(fos);} finally {fos.close();}log.info("download complete");} else {log.error("Not Found");log.info(EntityUtils.toString(entity));}} catch (Exception e) {log.error("downloading file from " + url + " occursing some error.");log.error(e);} finally {try {EntityUtils.consume(entity);response.close();httpclient.close();} catch (IOException e) {log.error(e);}}
}

可信任的SSL的HttpClient构建方法

/*** 构建可信任的https的HttpClient* * @return* @throws Exception*/
public static CloseableHttpClient buildHttpClient() throws Exception {SSLContext sslContext = new SSLContextBuilder().loadTrustMaterial(null,new TrustStrategy() {@Overridepublic boolean isTrusted(X509Certificate[] arg0, String arg1)throws CertificateException {return true;}}).build();SSLConnectionSocketFactory sslSocketFactory = new SSLConnectionSocketFactory(sslContext, new NoopHostnameVerifier());Registry<ConnectionSocketFactory> socketFactoryRegistry = RegistryBuilder.<ConnectionSocketFactory> create().register("http",PlainConnectionSocketFactory.getSocketFactory()).register("https", sslSocketFactory).build();PoolingHttpClientConnectionManager connectionManager = new PoolingHttpClientConnectionManager(socketFactoryRegistry);// set longer timeout valueRequestConfig requestConfig = RequestConfig.custom().setSocketTimeout(DEFAULT_TIMEOUT).setConnectTimeout(DEFAULT_TIMEOUT).setConnectionRequestTimeout(DEFAULT_TIMEOUT).build();CloseableHttpClient httpclient = HttpClients.custom().setSSLContext(sslContext).setConnectionManager(connectionManager).setDefaultRequestConfig(requestConfig).build();return httpclient;
}

辅助方法

// 判断字符串是否为空
private static boolean isBlank(String str) {int strLen;if (str == null || (strLen = str.length()) == 0) {return true;}for (int i = 0; i < strLen; i++) {if ((Character.isWhitespace(str.charAt(i)) == false)) {return false;}}return true;
}
// 将header信息按照
// 1,iso-8859-1转utf-8;2,URLDecoder.decode;3,MimeUtility.decodeText;
// 做处理，处理后的string就为编码正确的header信息（包括中文等）
private static String decodeHeader(String header)throws UnsupportedEncodingException {return MimeUtility.decodeText(URLDecoder.decode(new String(header.getBytes(Consts.ISO_8859_1), Consts.UTF_8),UTF_8));
}

http://stackoverflow.com/questions/10960409/how-do-i-save-a-file-downloaded-with-httpclient-into-a-specific-folder