最近需要用到在A專案裡面發起請求去請求B專案的介面，所以用到了HttpClient，將工具類記錄下，可設定get、post方式，也可以設定session和cookie等header

一、工具類HttpClientUtil

package Utils;

import java.io.*;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.Map;

public class HttpClientUtils {
    public static String doGet(String httpUrl) {
        HttpURLConnection connection = null;
        InputStream is = null;
        BufferedReader br = null;
        String result = null; //返回結果字串
        try {
            //建立遠端url連線物件
            URL url = new URL(httpUrl);
            //通過遠端url連線物件開啟一個連線，強轉成httpURLConnection類
            connection = (HttpURLConnection) url.openConnection();
            // 設定連線方式：get
            connection.setRequestMethod("GET");
            // 設定連線主機伺服器的超時時間：15000毫秒
            connection.setConnectTimeout(15000);
            // 設定讀取遠端返回的資料時間：60000毫秒
            connection.setReadTimeout(60000);
            // 傳送請求
            connection.connect();
            // 通過connection連線，獲取輸入流
            if (connection.getResponseCode() == 200) {
                is = connection.getInputStream();
                // 封裝輸入流is，並指定字符集
                br = new BufferedReader(new InputStreamReader(is, "UTF-8"));
                //存放資料
                StringBuffer sbf = new StringBuffer();
                String temp = null;
                while ((temp = br.readLine()) != null) {
                    sbf.append(temp);
                    sbf.append("\r\n");
                }
                result = sbf.toString();
            }
        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            //關閉資源
            if (null != br) {
                try {
                    br.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (null != is) {
                try {
                    is.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            //關閉遠端連線
            connection.disconnect();
        }
        return result;
    }

    public static String doPost(String httpUrl, String param, Map<String, String> headers) {
        HttpURLConnection connection = null;
        InputStream is = null;
        OutputStream os = null;
        BufferedReader br = null;
        String result = null;
        try {
            URL url = new URL(httpUrl);
            // 通過遠端url連線物件開啟連線
            connection = (HttpURLConnection) url.openConnection();
            // 設定連線請求方式
            connection.setRequestMethod("POST");
            // 設定連線主機伺服器超時時間：15000毫秒
            connection.setConnectTimeout(15000);
            // 設定讀取主機伺服器返回資料超時時間：60000毫秒
            connection.setReadTimeout(60000);

            // 預設值為：false，當向遠端伺服器傳送資料/寫資料時，需要設定為true
            connection.setDoOutput(true);
            // 預設值為：true，當前向遠端服務讀取資料時，設定為true，該引數可有可無
            connection.setDoInput(true);
            // 設定header請求頭
            for (String key : headers.keySet()) {
                connection.setRequestProperty(key, headers.get(key));
            }
            //通過連線物件獲取一個輸入流，向遠端讀// 通過連線物件獲取一個輸出流
            os = connection.getOutputStream();
            // 通過輸出流物件將引數寫出去/傳輸出去,它是通過位元組陣列寫出的
            //param請求引數應該是 name1=value1&name2=value2
            os.write(param.getBytes("utf-8"));
            if (connection.getResponseCode() == 200) {
                is = connection.getInputStream();
                // 對輸入流物件進行包裝:charset根據工作專案組的要求來設定
                br = new BufferedReader(new InputStreamReader(is, "UTF-8"));
                StringBuffer sbf = new StringBuffer();
                String temp = null;
                // 迴圈遍歷一行一行讀取資料
                while ((temp = br.readLine()) != null) {
                    sbf.append(temp);
                    sbf.append("\r\n");
                }
                result = sbf.toString();
            }
        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            //關閉資源
            if (null != br) {
                try {
                    br.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (null != os) {
                try {
                    os.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (null != is) {
                try {
                    is.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            connection.disconnect();
        }
        return result;
    }
}
 

二、main方法呼叫執行

package Utils;

import com.google.gson.Gson;

import java.util.HashMap;
import java.util.Map;

public class UtilDemo {
    public static void main(String[] args) {
        //get方式
        String getResult = HttpClientUtils.doGet("https://www.xxx.com");
        //json轉map
        Map result = new Gson().fromJson(getResult, Map.class);

        //---------------------------------------------------
        
        //post方式
        String webname = "https://www.xxx.com";
        //body請求引數
        Map<String, Object> body = new HashMap<>();
        body.put("key1", "value1");
        String sid = "sid111";
        String cookie = "cookiexxx";
        Map<String, String> headers = new HashMap<>();
        headers.put("cookie", cookie);
        String url = webname + "&sid=" + sid;
        //map轉json
        String param = new Gson().toJson(body);
        String postResult = HttpClientUtils.doPost(url, param, headers);
        //json轉map
        Map resutl2 = new Gson().fromJson(postResult, Map.class);
    }
}