java發送httpPost請求

最近調用外部廠商提供的Post接口，總結了幾種方法：

一、項目的maven依賴：

		<dependency>
			<groupId>org.apache.httpcomponents</groupId>
			<artifactId>httpcore</artifactId>
			<version>4.4.5</version>
		</dependency>
		<dependency>
			<groupId>org.apache.httpcomponents</groupId>
			<artifactId>httpclient</artifactId>
			<version>4.5.6</version>
		</dependency>
		<dependency>
			<groupId>org.apache.httpcomponents</groupId>
			<artifactId>httpmime</artifactId>
			<version>4.5.2</version>
		</dependency>
		<!-- https://mvnrepository.com/artifact/com.google.guava/guava -->
		<dependency>
			<groupId>com.google.guava</groupId>
			<artifactId>guava</artifactId>
			<version>27.0.1-jre</version>
		</dependency>
		<!-- https://mvnrepository.com/artifact/org.slf4j/slf4j-api -->
		<dependency>
			<groupId>org.slf4j</groupId>
			<artifactId>slf4j-api</artifactId>
			<version>1.7.25</version>
		</dependency>
		<dependency>
			<groupId>com.alibaba</groupId>
			<artifactId>fastjson</artifactId>
			<version>1.2.28</version>
		</dependency>

二.post請求代碼：

1.含上傳圖片（非JSON）：

	public static String requestOCRForHttp(String url, Map<String, String> requestParams, String filePathAndName)
			throws Exception {
		String result = null;
		CloseableHttpClient httpClient = HttpClients.createDefault();
		/** HttpPost */
		HttpPost httpPost = new HttpPost(url);
		MultipartEntity reqEntity = new MultipartEntity(); // 建立多文件實例
		FileBody filebody = new FileBody(new File(filePathAndName));
		reqEntity.addPart("pic", filebody);// upload爲請求後臺的File upload;
		for (String key : requestParams.keySet()) {
			String value = requestParams.get(key);
			reqEntity.addPart(key, new StringBody(value, Charset.forName("utf-8")));
		}
		httpPost.setEntity(reqEntity); // 設置實體
		/** HttpResponse */
		CloseableHttpResponse httpResponse = httpClient.execute(httpPost);
		try {
			HttpEntity httpEntity = httpResponse.getEntity();
			result = EntityUtils.toString(httpEntity, "utf-8");
			EntityUtils.consume(httpEntity);
		} finally {
			try {
				if (httpResponse != null) {
					httpResponse.close();
				}
			} catch (IOException e) {
				logger.info("## release resouce error ##" + e);
			}
		}
		return result;
	}

2.post的String參數（非JSON）

	public static String requestOCRForHttp(String url, Map<String, String> requestParams) throws Exception {
		String result = null;
		CloseableHttpClient httpClient = HttpClients.createDefault();
		/** HttpPost */
		HttpPost httpPost = new HttpPost(url);
		List<NameValuePair> params = new ArrayList<NameValuePair>();
		Iterator<Entry<String, String>> it = requestParams.entrySet().iterator();
//		System.out.println(params.toString());
		while (it.hasNext()) {
			Entry<String, String> en = it.next();
			String key = en.getKey();
			String value = en.getValue();
			if (value != null) {
				params.add(new BasicNameValuePair(key, value));
			}
		}
		httpPost.setEntity(new UrlEncodedFormEntity(params, "UTF-8"));
		/** HttpResponse */
		CloseableHttpResponse httpResponse = httpClient.execute(httpPost);
		try {
			HttpEntity httpEntity = httpResponse.getEntity();
			result = EntityUtils.toString(httpEntity, "utf-8");
			EntityUtils.consume(httpEntity);
		} finally {
			try {
				if (httpResponse != null) {
					httpResponse.close();
				}
			} catch (IOException e) {
				logger.info("## release resouce error ##" + e);
			}
		}
		return result;
	}

3.POST請求（JSON）：

	public static String sendHttpPost(String url, String JSONBody) throws Exception {
		CloseableHttpClient httpClient = HttpClients.createDefault();
		HttpPost httpPost = new HttpPost(url);
		httpPost.addHeader("Content-Type", "application/json");
		httpPost.setEntity(new StringEntity(JSONBody));
		CloseableHttpResponse response = httpClient.execute(httpPost);
//		System.out.println(response.getStatusLine().getStatusCode() + "\n");
		HttpEntity entity = response.getEntity();
		String responseContent = EntityUtils.toString(entity, "UTF-8"); 
//		System.out.println(responseContent);
		response.close();
		httpClient.close();
		return responseContent;
	}