HTTP请求工具类

• import java.io.BufferedReader;
  import java.io.IOException;
  import java.io.InputStreamReader;
  import java.net.HttpURLConnection;
  import java.net.URL;public class HttpUtils {/*** 发送GET请求并获取响应结果* * @param url 请求的URL* @return 响应结果，如果请求失败则返回null*/public static String sendGetRequest(String url) {HttpURLConnection connection = null;BufferedReader reader = null;StringBuilder result = new StringBuilder();try {URL requestUrl = new URL(url);connection = (HttpURLConnection) requestUrl.openConnection();connection.setRequestMethod("GET");connection.setConnectTimeout(5000);connection.setReadTimeout(5000);int responseCode = connection.getResponseCode();if (responseCode == HttpURLConnection.HTTP_OK) {reader = new BufferedReader(new InputStreamReader(connection.getInputStream()));String line;while ((line = reader.readLine()) != null) {result.append(line);}}} catch (IOException e) {e.printStackTrace();} finally {if (reader != null) {try {reader.close();} catch (IOException e) {e.printStackTrace();}}if (connection != null) {connection.disconnect();}}return result.toString();}/*** 发送POST请求并获取响应结果* * @param url    请求的URL* @param params 请求参数，格式为key=value，多个参数之间用&连接* @return 响应结果，如果请求失败则返回null*/public static String sendPostRequest(String url, String params) {HttpURLConnection connection = null;BufferedReader reader = null;StringBuilder result = new StringBuilder();try {URL requestUrl = new URL(url);connection = (HttpURLConnection) requestUrl.openConnection();connection.setRequestMethod("POST");connection.setConnectTimeout(5000);connection.setReadTimeout(5000);connection.setDoOutput(true);connection.getOutputStream().write(params.getBytes("UTF-8"));int responseCode = connection.getResponseCode();if (responseCode == HttpURLConnection.HTTP_OK) {reader = new BufferedReader(new InputStreamReader(connection.getInputStream()));String line;while ((line = reader.readLine()) != null) {result.append(line);}}} catch (IOException e) {e.printStackTrace();} finally {if (reader != null) {try {reader.close();} catch (IOException e) {e.printStackTrace();}}if (connection != null) {connection.disconnect();}}return result.toString();}/*** 发送HTTP请求* * @param method 请求方法，如GET、POST等* @param url    请求的URL* @param params 请求参数，格式为key=value，多个参数之间用&连接* @return 响应结果，如果请求失败则返回null*/public static String sendHttpRequest(String method, String url, String params) {if ("GET".equalsIgnoreCase(method)) {return sendGetRequest(url);} else if ("POST".equalsIgnoreCase(method)) {return sendPostRequest(url, params);}return null;}/*** *调用接口* @param url,method,json字符串参数* @return com.daasan.common.core.api.R<?>**/@Overridepublic R<?> callApi(String url, String method, String paramsStr) {//校验必填参数if (StringUtils.isBlank(url)){throw new BsException("请求路径不能为空！");}if (StringUtils.isBlank(method)){throw new BsException("请求方式不能为空！");}// 根据请求方法构建不同的请求对象HttpMethod httpMethod = HttpMethod.resolve(method.toUpperCase());ResponseEntity<String> response;//将json字符串参数转为map类型的参数Map<String, Object> params = ScreenConfigUtil.jsonToMap(paramsStr);//调用接口if (httpMethod == HttpMethod.GET) {// GET请求String queryString = ScreenConfigUtil.buildQueryString(params);if (StringUtils.isNotBlank(queryString)) {url = url + "?" + queryString;}response = restTemplate.getForEntity(url, String.class);} else {// POST、PUT等请求HttpHeaders headers = new HttpHeaders();headers.set("Content-Type", "application/json");HttpEntity<Object> requestEntity = new HttpEntity<>(params, headers);response = restTemplate.exchange(url, httpMethod, requestEntity, String.class);}// 获取接口调用结果（json格式字符串）String body = response.getBody();//如果接口没有返回值，则返回调用成功的消息提示if (StringUtils.isBlank(body)){return R.success("接口调用成功！");}//如果接口返回结果以“[”开头，则转换为List<Map<String, Object>>if (body.startsWith("[")){//将结果由json格式字符串转换为List<Map<String, Object>>List<Map<String, Object>> result = ScreenConfigUtil.jsonToList(body);if (CollectionUtil.isNotEmpty(result)){return R.data(result);}}//如果接口返回结果以“{”开头，则转化为Map<String, Object>if (body.startsWith("{")){Map<String, Object> result = ScreenConfigUtil.jsonToMap(body);if (result != null && !result.isEmpty()){return R.data(result);}}return R.data(body);}}