一：C#從http上取JSON數(shù)據(jù)
向服務(wù)器請求數(shù)據(jù)后，一般時XML或JSON:(以JSON為例)
在C#中WinForm為例操作：
Util工具類：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Net;
using System.IO;

namespace WindowsUtil
{
    public class HttpUitls
    {
         public static string GetHtml(string Url)
        {
        	//可以看看request屬性，取所需要的內(nèi)容，這里參數(shù)可以改為實體類，向方法傳參
        	//還額外有個cookie字段很重要！??！
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(Url);//請求地址
            request.Method = "GET";//請求方法
            request.AllowAutoRedirect = true;//重定向
            request.Proxy = null;//代理信息
            request.KeepAlive = false;
            request.ContentType = "application/json; charset=UTF-8";
            request.AutomaticDecompression = DecompressionMethods.GZip;

            HttpWebResponse response = (HttpWebResponse)request.GetResponse();
            Stream myResponseStream = response.GetResponseStream();
            StreamReader myStreamReader = new StreamReader(myResponseStream, Encoding.UTF8);
            string retString = myStreamReader.ReadToEnd();

            myStreamReader.Close();
            myResponseStream.Close();

            if (response != null)
            {
                response.Close();
            }
            if (request != null)
            {
                request.Abort();
            }
            return retString;
        }

        public static string Post(string Url, string Data, string Referer)
        {
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(Url);
            request.Method = "POST";
            request.Referer = Referer;
            byte[] bytes = Encoding.UTF8.GetBytes(Data);
            request.ContentType = "application/x-www-form-urlencoded";
            request.ContentLength = bytes.Length;
            Stream myResponseStream = request.GetRequestStream();
            myResponseStream.Write(bytes, 0, bytes.Length);

            HttpWebResponse response = (HttpWebResponse)request.GetResponse();
            StreamReader myStreamReader = new StreamReader(response.GetResponseStream(), Encoding.UTF8);
            string retString = myStreamReader.ReadToEnd();

            myStreamReader.Close();
            myResponseStream.Close();

            if (response != null)
            {
                response.Close();
            }
            if (request != null)
            {
                request.Abort();
            }
            return retString;
        }  
    }
}

窗體中點(diǎn)擊發(fā)生事件：

private string searchUrl = $"http://www.chinamoney.com.cn/ags/ms/cm-u-bk-fx/RefRateHis?lang=cn&";

private void Btnsearch_Click(object sender, EventArgs e)
{
	try
	{
		DateTime dateTime = Convert.ToDateTime(this.Datepick.Month);
		string hbxz = "ALL";
		if (!string.IsNullOrEmpty(this.Ddlhbxz.SelectedValue))
		{
		    hbxz = this.Ddlhbxz.SelectedValue;
		}
		string Url = searchUrl + "startDateTool=" + DateHelper.GetCurMonthFirstDay(dateTime) + "&" + "endDateTool=" + DateHelper.GetCurMonthLastDay(dateTime) + "&currencyCode=" + hbxz;
		var result = PostHelper.Get(Url);
		var rootobject= JsonConvert.DeserializeObject<Rootobject> (result);
		///
		//處理獲取到的信息源
		///
	}
    catch(Exception ex)
    {
        MessageBox.Show(ex.Message);
    }   
}              

二：公司中已經(jīng)封好的方法使用：
第一步：先添加引用；
Universal.Kits
第二步：書寫方法；

private string get(string url)
{
    var result = new HttpHelper().GetHtml(new HttpItem
    {
        URL = url,//請求地址
        Method="get",//方法
        Allowautoredirect=true//重定向
    }) ;
    if (result.StatusCode == System.Net.HttpStatusCode.OK)
    {
        return result.Html;
    }
    return null;       
}

第三步：調(diào)用方法獲取數(shù)據(jù)；
第四步：轉(zhuǎn)為獲取到的數(shù)據(jù)源實體類；
注：Rootobject是封好的實體類。
result是上述方法的返回字符串。

var rootobject= JsonConvert.DeserializeObject<Rootobject> (result);

三：http獲取網(wǎng)頁界面所顯示數(shù)據(jù)
第一步：封好的方法：

public static string HttpGet(string url)
{
    //cookie是要在網(wǎng)頁F12看到的cookie “復(fù)制過來”
    string cookiestr = "cookies";
    //創(chuàng)建請求
    HttpWebRequest httpWebRequest=(HttpWebRequest)WebRequest.Create(url);
    //請求方式
    httpWebRequest.Method = "GET";
    //設(shè)置請求超時時間
    httpWebRequest.Timeout = 10000;
    //設(shè)置cookie
    httpWebRequest.Headers.Add("Cookie", cookiestr);
    //發(fā)送請求
    HttpWebResponse httpWebResponse=(HttpWebResponse)httpWebRequest.GetResponse();
    //利用Stream流讀取返回數(shù)據(jù)
    StreamReader streamReader=new StreamReader(httpWebResponse.GetResponseStream());
    //獲得最終數(shù)據(jù)，一般是JSON
    string responseContent=streamReader.ReadToEnd();
    streamReader.Close();
    httpWebResponse.Close();

    //返回到的一般是JSON格式的字符串
    return responseContent;
}

第二步：調(diào)用方法

 string txt = HttpGet(@"url");
 HtmlDocument doc = new HtmlDocument();
 doc.LoadHtml(txt);
 var div = doc.DocumentNode.SelectNodes("http://div[@id='all-list']//ul//li//a[@class='title']");//div的ID class找到具體位置
 foreach (HtmlNode node in div)
 {
     string href = node.GetAttributeValue("href", "");
     Console.WriteLine(string.Format("{0}-----------{1}",
     node.InnerText,
     node.GetAttributeValue("href", "")+"\r\n"));
 }
 Console.ReadKey();

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