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傳送GET方法的請求
     *
     * @param url   傳送請求的URL
     * @param param 請求引數，請求引數應該是 name1=value1&name2=value2 的形式。
     * @return URL 所代表遠端資源的響應結果
     */
    public static String sendJsonGet(String url, String param) {
        String result = "";
        BufferedReader in = null;
        try {
            String urlNameString = url + "?" + param;
            URL realUrl = new URL(urlNameString);
            // 開啟和URL之間的連線
            HttpURLConnection connection = (HttpURLConnection) realUrl.openConnection();
            connection.setRequestMethod("GET");
            // 設定通用的請求屬性
            connection.setRequestProperty("accept", "*/*");
            connection.setRequestProperty("connection", "Keep-Alive");
            connection.setRequestProperty("user-agent",
                    "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
            // 建立實際的連線
            connection.connect();
            // 獲取所有響應頭欄位
            Map<String, List<String>> map = connection.getHeaderFields();
            // 遍歷所有的響應頭欄位
            for (String key : map.keySet()) {
                System.out.println(key + "--->" + map.get(key));
            }
            // 定義 BufferedReader輸入流來讀取URL的響應
            in = new BufferedReader(new InputStreamReader(
                    connection.getInputStream()));
            String line = "";
            while ((line = in.readLine()) != null) {
                result += line;
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        // 使用finally塊來關閉輸入流
        finally {
            try {
                if (in != null) {
                    in.close();
                }
            } catch (Exception e2) {
                e2.printStackTrace();
            }
        }
        return result;
    }

    /**
     * 向指定 URL 傳送POST方法的請求
     *
     * @param url   傳送請求的 URL
     * @param param 請求引數，請求引數應該是 name1=value1&name2=value2 的形式。
     * @return 所代表遠端資源的響應結果
     */
    public static String sendPost(String url, String param) {
        PrintWriter out = null;
        BufferedReader in = null;
        String result = "";
        try {
            URL realUrl = new URL(url);
            // 開啟和URL之間的連線
            HttpURLConnection conn = (HttpURLConnection) realUrl.openConnection();
            // 設定通用的請求屬性
            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)");
            // 傳送POST請求必須設定如下兩行
            conn.setDoOutput(true);
            conn.setDoInput(true);
            // 獲取URLConnection物件對應的輸出流
            out = new PrintWriter(conn.getOutputStream());
            // 傳送請求引數
            out.print(param);
            // flush輸出流的緩衝
            out.flush();
            // 定義BufferedReader輸入流來讀取URL的響應
            in = new BufferedReader(
                    new InputStreamReader(conn.getInputStream()));
            String line;
            while ((line = in.readLine()) != null) {
                result += line;
            }
        } catch (Exception e) {
            System.out.println("傳送 POST 請求出現異常！" + e);
            e.printStackTrace();
        }
        //使用finally塊來關閉輸出流、輸入流
        finally {
            try {
                if (out != null) {
                    out.close();
                }
                if (in != null) {
                    in.close();
                }
            } catch (IOException ex) {
                ex.printStackTrace();
            }
        }
        return result;
    }

    /**
     * 傳送post表單請求
     *
     * @param url
     * @param params
     * @return
     */
    public static String httpForm(String url, Map<String, String> params) {
        URL u = null;
        HttpURLConnection con = null;
        // 構建請求引數
        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());
        // 嘗試傳送請求
        try {
            u = new URL(url);
            con = (HttpURLConnection) u.openConnection();
            // POST 只能為大寫，嚴格限制，post會不識別
            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();
            }
        }

        // 讀取返回內容
        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();
    }

}