使用jdk自带API调用外部接口

╰+哭是因爲堅強的太久メ 2021-11-05 06:14 285阅读 0赞

## 工具类 ##

import org.slf4j.Logger;
    import org.slf4j.LoggerFactory;
    
    import java.io.BufferedReader;
    import java.io.IOException;
    import java.io.InputStreamReader;
    import java.io.UnsupportedEncodingException;
    import java.net.HttpURLConnection;
    import java.net.MalformedURLException;
    import java.net.URL;
    import java.net.URLEncoder;
    import java.util.HashMap;
    import java.util.Map;
    
    /** * @author 72038611 */
    public class HttpClientUtils { 
    
        public static final Logger LOGGER = LoggerFactory.getLogger(HttpClientUtils.class);
    
        private HttpClientUtils() { 
        }
    
        /** * 向指定URL发送GET方法的请求 * * @param url 发送请求的URL 例如：http://localhost:8080/demo/login * @param param 请求参数 例：{ "userName":"admin", "password":"123456" } * @return URL 所代表远程资源的响应结果 */
        public static String sendGet(String url, Map<String, Object> param) throws Exception { 
            StringBuilder result = new StringBuilder();
            BufferedReader in = null;
            try { 
                URL realUrl = createURL(url, param);
                HttpURLConnection conn = (HttpURLConnection) realUrl.openConnection();
                conn.setRequestProperty("accept", "*/*");
                conn.setRequestProperty("connection", "Keep-Alive");
                conn.setRequestProperty("Charset", "UTF-8");
                conn.connect();
                in = new BufferedReader(new InputStreamReader(
                        conn.getInputStream()));
                String line;
                while ((line = in.readLine()) != null) { 
                    result.append(line);
                }
            } catch (Exception e) { 
                LOGGER.error("发送GET请求出现异常！");
                throw e;
            } finally { 
                try { 
                    if (in != null) { 
                        in.close();
                    }
                } catch (Exception e2) { 
                    LOGGER.error("流关闭异常！", e2);
                }
            }
            return result.toString();
        }
    
    
        /** * 向指定URL发送GET方法的请求 * * @param url 例如：http://localhost:8080/demo * @return result BufferedReader流 */
        public static BufferedReader sendGet(String url) throws Exception { 
            URL realUrl = createURL(url, new HashMap<String, Object>(0));
            HttpURLConnection conn = (HttpURLConnection) realUrl.openConnection();
            conn.setRequestProperty("accept", "*/*");
            conn.setRequestProperty("connection", "Keep-Alive");
            conn.setRequestProperty("Charset", "UTF-8");
            conn.connect();
            BufferedReader result = new BufferedReader(new InputStreamReader(
                    conn.getInputStream()));
            return result;
        }
    
        /** * 向指定 URL 发送POST方法的请求 * * @param url 发送请求的URL 例如：http://localhost:8080/demo/login * @param param 请求参数 例：{ "userName":"admin", "password":"123456" } * @return 所代表远程资源的响应结果 */
        public static String sendPost(String url, Map<String, Object> param) { 
            BufferedReader in = null;
            StringBuilder result = new StringBuilder();
            try { 
                URL realUrl = createURL(url, param);
                // 打开和URL之间的连接
                HttpURLConnection conn = (HttpURLConnection) realUrl.openConnection();
                // 发送POST请求必须设置
                conn.setDoOutput(true);
                conn.setDoInput(true);
                conn.setRequestMethod("POST");
                conn.setUseCaches(false);
                conn.setInstanceFollowRedirects(true);
                // 设置通用的请求属性
                conn.setRequestProperty("Charset", "UTF-8");
                conn.setRequestProperty("Content-Type", "application/json; charset=UTF-8");
                conn.connect();
                // 定义BufferedReader输入流来读取URL的响应
                in = new BufferedReader(
                        new InputStreamReader(conn.getInputStream()));
                String line;
                while ((line = in.readLine()) != null) { 
                    result.append(line);
                }
            } catch (Exception e) { 
                System.out.println("发送 POST 请求出现异常！" + e);
                e.printStackTrace();
            } finally { 
                try { 
                    if (in != null) { 
                        in.close();
                    }
                } catch (IOException ex) { 
                    ex.printStackTrace();
                }
            }
            return result.toString();
        }
    
    
        private static URL createURL(String url, Map<String, Object> param) throws MalformedURLException { 
            if (param == null || param.size() == 0) { 
                return new URL(url);
            }
            StringBuilder sb = new StringBuilder(url);
            sb.append("?");
            for (String key : param.keySet()) { 
                sb.append(key);
                sb.append("=");
                sb.append(encode(String.valueOf(param.get(key))));
                sb.append("&");
            }
            return new URL(sb.substring(0, sb.length() - 1));
        }
    
        private static String encode(String text) { 
            try { 
                return URLEncoder.encode(text, "UTF-8");
            } catch (UnsupportedEncodingException e) { 
                e.printStackTrace();
            }
            return null;
        }
    }