Http请求

快来打我* 2022-04-04 13:58 394阅读 0赞

package fun.lovey.http;
     
    import java.io.*;
    import java.net.HttpURLConnection;
    import java.net.URL;
    import java.util.List;
    import java.util.Map;
     
    /**
     * java net package
     *
     * @author liwc
     * @version V1.0
     * @date 2018-06-25 10:51
     */
    public class HttpRequestTool {
     
        /**
         * 向指定URL发送GET方法的请求
         *
         * @param url   发送请求的URL
         * @param param 请求参数，请求参数应该是 name1=value1&name2=value2 的形式。
         * @return URL 所代表远程资源的响应结果
         */
        public static String sendJsonGet(String url, String param) {
            String result = "";
            BufferedReader in = null;
            try {
                String urlNameString = url + "?" + param;
                URL realUrl = new URL(urlNameString);
                // 打开和URL之间的连接
                HttpURLConnection connection = (HttpURLConnection) realUrl.openConnection();
                connection.setRequestMethod("GET");
                // 设置通用的请求属性
                connection.setRequestProperty("accept", "*/*");
                connection.setRequestProperty("connection", "Keep-Alive");
                connection.setRequestProperty("user-agent",
                        "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
                // 建立实际的连接
                connection.connect();
                // 获取所有响应头字段
                Map<String, List<String>> map = connection.getHeaderFields();
                // 遍历所有的响应头字段
                for (String key : map.keySet()) {
                    System.out.println(key + "--->" + map.get(key));
                }
                // 定义 BufferedReader输入流来读取URL的响应
                in = new BufferedReader(new InputStreamReader(
                        connection.getInputStream()));
                String line = "";
                while ((line = in.readLine()) != null) {
                    result += line;
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
            // 使用finally块来关闭输入流
            finally {
                try {
                    if (in != null) {
                        in.close();
                    }
                } catch (Exception e2) {
                    e2.printStackTrace();
                }
            }
            return result;
        }
     
        /**
         * 向指定 URL 发送POST方法的请求
         *
         * @param url   发送请求的 URL
         * @param param 请求参数，请求参数应该是 name1=value1&name2=value2 的形式。
         * @return 所代表远程资源的响应结果
         */
        public static String sendPost(String url, String param) {
            PrintWriter out = null;
            BufferedReader in = null;
            String result = "";
            try {
                URL realUrl = new URL(url);
                // 打开和URL之间的连接
                HttpURLConnection conn = (HttpURLConnection) realUrl.openConnection();
                // 设置通用的请求属性
                conn.setRequestMethod("POST");
                conn.setRequestProperty("accept", "*/*");
                conn.setRequestProperty("connection", "Keep-Alive");
                conn.setRequestProperty("user-agent", "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
                // 发送POST请求必须设置如下两行
                conn.setDoOutput(true);
                conn.setDoInput(true);
                // 获取URLConnection对象对应的输出流
                out = new PrintWriter(conn.getOutputStream());
                // 发送请求参数
                out.print(param);
                // flush输出流的缓冲
                out.flush();
                // 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 += line;
                }
            } catch (Exception e) {
                System.out.println("发送 POST 请求出现异常！" + e);
                e.printStackTrace();
            }
            //使用finally块来关闭输出流、输入流
            finally {
                try {
                    if (out != null) {
                        out.close();
                    }
                    if (in != null) {
                        in.close();
                    }
                } catch (IOException ex) {
                    ex.printStackTrace();
                }
            }
            return result;
        }
     
        /**
         * 发送post表单请求
         *
         * @param url
         * @param params
         * @return
         */
        public static String httpForm(String url, Map<String, String> params) {
            URL u = null;
            HttpURLConnection con = null;
            // 构建请求参数
            StringBuffer sb = new StringBuffer();
            if (params != null) {
                params.forEach((x, y) -> {
                    sb.append(x);
                    sb.append("=");
                    sb.append(y);
                    sb.append("&");
     
                });
                sb.substring(0, sb.length() - 1);
            }
            System.out.println("send_url:" + url);
            System.out.println("send_data:" + sb.toString());
            // 尝试发送请求
            try {
                u = new URL(url);
                con = (HttpURLConnection) u.openConnection();
                // POST 只能为大写，严格限制，post会不识别
                con.setRequestMethod("POST");
                con.setDoOutput(true);
                con.setDoInput(true);
                con.setUseCaches(false);
                con.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
                OutputStreamWriter osw = new OutputStreamWriter(con.getOutputStream(), "UTF-8");
                osw.write(sb.toString());
                osw.flush();
                osw.close();
            } catch (Exception e) {
                e.printStackTrace();
            } finally {
                if (con != null) {
                    con.disconnect();
                }
            }
     
            // 读取返回内容
            StringBuffer buffer = new StringBuffer();
            try {
                BufferedReader br = new BufferedReader(new InputStreamReader(con.getInputStream(), "UTF-8"));
                String temp;
                while ((temp = br.readLine()) != null) {
                    buffer.append(temp);
                    buffer.append("\n");
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
            return buffer.toString();
        }
     
    }