HttpWebRequest实现读取天气预报信息 -优快云博客

本文介绍了一个使用ASP.NET实现的简单天气预报查询应用。该应用允许用户从下拉列表中选择城市，并通过按钮触发请求来获取并显示选定城市的天气信息。应用通过向新浪天气API发送POST请求获取天气数据。

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< HTML >

< HEAD >

< title > Weather </ title >

< meta content ="Microsoft Visual Studio .NET 7.1" name ="GENERATOR" >

< meta content ="C#" name ="CODE_LANGUAGE" >

< meta content ="JavaScript" name ="vs_defaultClientScript" >

< meta content ="http://schemas.microsoft.com/intellisense/ie5" name ="vs_targetSchema" >

</ HEAD >

< body MS_POSITIONING ="GridLayout" >

< form id ="Form1" method ="post" runat ="server" >

< TABLE id ="Table1" style ="Z-INDEX: 110; LEFT: 296px; WIDTH: 320px; POSITION: absolute; TOP: 24px; HEIGHT: 231px"

cellSpacing ="1" cellPadding ="1" width ="320" bgColor ="#ffff99" border ="1" >

< TR >

< TD >< asp:label id ="Label1" runat ="server" Font-Italic ="True" > ==天气预报== </ asp:label ></ TD >

< TD >< asp:dropdownlist id ="ddlcity" runat ="server" >

< asp:ListItem Value ="深圳" Selected ="True" > 深圳 </ asp:ListItem >

< asp:ListItem Value ="广州" > 广州 </ asp:ListItem >

< asp:ListItem Value ="上海" > 上海 </ asp:ListItem >

< asp:ListItem Value ="北京" > 北京 </ asp:ListItem >

< asp:ListItem Value ="天津" > 天津 </ asp:ListItem >

< asp:ListItem Value ="武汉" > 武汉 </ asp:ListItem >

< asp:ListItem Value ="重庆" > 重庆 </ asp:ListItem >

< asp:ListItem Value ="成都" > 成都 </ asp:ListItem >

< asp:ListItem Value ="南京" > 南京 </ asp:ListItem >

< asp:ListItem Value ="香港" > 香港 </ asp:ListItem >

< asp:ListItem Value ="澳门" > 澳门 </ asp:ListItem >

</ asp:dropdownlist ></ TD >

< TD >< asp:button id ="Button1" runat ="server" Text ="读取" ></ asp:button ></ TD >

</ TR >

< TR >

< TD colSpan ="3" >< asp:label id ="l_city" runat ="server" ></ asp:label ></ TD >

</ TR >

< TR >

< TD colSpan ="3" >< asp:label id ="l_wea" runat ="server" ></ asp:label ></ TD >

</ TR >

< TR >

< TD colSpan ="3" >< asp:label id ="l_sky" runat ="server" ></ asp:label ></ TD >

</ TR >

< TR >

< TD colSpan ="3" >< asp:label id ="l_date" runat ="server" ></ asp:label ></ TD >

</ TR >

< TR >

< TD colSpan ="3" >< asp:label id ="l_w1" runat ="server" ></ asp:label ></ TD >

</ TR >

< TR >

< TD colSpan ="3" >< asp:label id ="l_w2" runat ="server" ></ asp:label ></ TD >

</ TR >

< TR >

< TD colSpan ="3" >< asp:label id ="l_w3" runat ="server" ></ asp:label ></ TD >

</ TR >

< TR >

< TD colSpan ="3" >< asp:label id ="l_w4" runat ="server" ></ asp:label ></ TD >

</ TR >

</ TABLE >

</ form >

</ body >

</ HTML >2.cs
添加如下应用

using System.Net;

using System.IO;

页面代码

public class Weather : System.Web.UI.Page

{

protected System.Web.UI.WebControls.Label l_date;

protected System.Web.UI.WebControls.Label l_city;

protected System.Web.UI.WebControls.Label l_wea;

protected System.Web.UI.WebControls.Label l_sky;

protected System.Web.UI.WebControls.Label l_w1;

protected System.Web.UI.WebControls.Label l_w2;

protected System.Web.UI.WebControls.Button Button1;

protected System.Web.UI.WebControls.Label Label1;

protected System.Web.UI.WebControls.Label l_w3;

protected System.Web.UI.WebControls.Label l_w4;

protected System.Web.UI.WebControls.DropDownList ddlcity;

private void Page_Load(object sender, System.EventArgs e)

{

if (!Page.IsPostBack)

{

writeWeatherInfo(ddlcity.SelectedValue);

writeWeather(ddlcity.SelectedValue);

}

#region getWeatherByCity 通过城市过虑

public string getWeatherByCity(string city)

{

string temp = null;

try

{

string strURL = "http://weather.news.sina.com.cn/cgi-bin/figureWeather/search.cgi";

HttpWebRequest request= (HttpWebRequest)WebRequest.Create(strURL);//使用 WebRequest.Create 方法初始化 HttpWebRequest 的一个新实例。如果 URI 的方案是 http:// 或 https://，则 Create 将返回 HttpWebRequest 实例。

request.Method="POST"; //Post请求方式

request.ContentType="application/x-www-form-urlencoded"; //内容类型

string paraUrlCoded = System.Web.HttpUtility.UrlEncode("city"); //参数经过URL编码

paraUrlCoded = paraUrlCoded + "=" + System.Web.HttpUtility.UrlEncode(city, System.Text.Encoding.GetEncoding("GB2312"));

byte[] payload = System.Text.Encoding.GetEncoding("GB2312").GetBytes(paraUrlCoded); //将URL编码后的字符串转化为字节

request.ContentLength = payload.Length; //设置请求的ContentLength

Stream writer = request.GetRequestStream(); //获得请求流

writer.Write(payload,0,payload.Length); //将请求参数写入流

writer.Close(); //关闭请求流

HttpWebResponse response = (HttpWebResponse)request.GetResponse(); //获得响应流

Stream s= response.GetResponseStream();

StreamReader objReader = new StreamReader(s,System.Text.Encoding.GetEncoding("GB2312"));

string HTML = "";

string sLine = "";

int i = 0;

while (sLine!=null)

{

i++;

sLine = objReader.ReadLine();

if (sLine!=null)

HTML += sLine;

}

HTML = HTML.Replace("<","<");

HTML = HTML.Replace(">",">");

int start,stop;

//start = HTML.IndexOf("<img src=/"http://image2.sina.com.cn/dy/weather/images/figure/",0,HTML.Length);

start = HTML.IndexOf("<table border=0 cellpadding=0 cellspacing=0 style=/"margin:5px;/">",0,HTML.Length);

stop = HTML.IndexOf("<td background=http://image2.sina.com.cn/dy/weather/images",start);

temp = HTML.Substring(start, stop - start);

}

catch (Exception x)

{

}

return temp;

}

#endregion

#region writeWeatherInfo 显示处理后的信息

private void writeWeatherInfo(string city)

{

int start,stop;

string weather1,weather2,wea;

string wea_city = getWeatherByCity(city);

wea_city = wea_city.Replace(" ","");

start = wea_city.IndexOf("<b>",0,wea_city.Length);

stop = wea_city.IndexOf("</b>", start);

weather1 = wea_city.Substring(start, stop-start).Trim() + " ";

weather1 = weather1.Substring(3,8).Trim();

start = wea_city.IndexOf("<tdstyle=/"font-size:40px;font-family:TimesNewRoman;font-weight:bold;/">",0,wea_city.Length);

stop = wea_city.IndexOf("℃",start) + 40;

weather2 = wea_city.Substring(start, stop-start);

weather2 = weather2.Substring(stop-start-42,40).Trim();

weather2 = weather2.Replace("/t","");

start = wea_city.IndexOf("<fontcolor=#183888><b>", 0, wea_city.Length);

stop = wea_city.IndexOf("</b></font>",start);

wea = wea_city.Substring(start,stop-start);

wea = wea.Substring(22,wea.Length-22) + "kbrk";

wea = wea.Replace("/t", "");

wea = wea.Replace(">", "k");

wea = wea.Replace("<", "k");

wea = wea.Replace("kbrk", "k");

string [] wall = null;

char[] seperator = {'k'};

wall = wea.Split(seperator);

l_city.Text = "[城市]：" + city;//城市

l_wea.Text = "[天气]：" + weather1;//天气

l_sky.Text = "[温度]：" + weather2;//温度

l_date.Text = wall[0];//日期

l_w1.Text = wall[1];//风向

l_w2.Text = wall[2];//风力

l_w3.Text = wall[3]; //空气质量

l_w4.Text = wall[4]; //紫外线强度

}

#endregion

#region writeWeather 直接显示读取到的信息

private void writeWeather(string city)

{

string wea_city = getWeatherByCity(city);

Response.Write(wea_city);

}

#endregion

#region Button1_Click

private void Button1_Click(object sender, System.EventArgs e)

{

writeWeatherInfo(ddlcity.SelectedValue);

writeWeather(ddlcity.SelectedValue);

}

#endregion

#region Web Form Designer generated code

override protected void OnInit(EventArgs e)

{

// CODEGEN: This call is required by the ASP.NET Web Form Designer.

InitializeComponent();

base.OnInit(e);

}

/// <summary>

/// Required method for Designer support - do not modify

/// the contents of this method with the code editor.

/// </summary>

private void InitializeComponent()

{

this.Button1.Click += new System.EventHandler(this.Button1_Click);

this.Load += new System.EventHandler(this.Page_Load);

}

#endregion

}