C# 使用WebRequest发送post和get请求-Toy模板网

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1.get请求方式

1.1不需要请求参数时

1.2请求参数可以用表单数据(键值对)拼接时

2.POST请求方式

2.1请求参数为json字符串格式时

2.2请求参数为表单数据(键值对)格式时

2.3请求参数为多分部数据(复合式表单)格式时，(以上传文件接口为例)

本文主要介绍了通过C#中的WebRequest来发送post和get两种请求方式的过程。

1.get请求方式

1.1不需要请求参数时

url为请求的接口地址

private string GetData(string url)
{
    string result = string.Empty;
    string error = string.Empty;
    try
    {
        HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
        request.Timeout = 20000;  //超时时间
        request.Method = "GET";  //请求方式
        request.KeepAlive = true; //解决GetResponse操作超时问题
        request.Headers.Add("Authorization", "token"); //如果接口需要鉴权, 把"token"换成自己需要的

        //通过HttpWebRequest的GetResponse()方法建立HttpWebResponse,强制类型转换
        HttpWebResponse response = (HttpWebResponse)request.GetResponse();
		
        //获取响应内容，返回的数据格式: {"status":"success","msg":"成功","data":{"info": "example"}}
        string postContent = new StreamReader(response.GetResponseStream()).ReadToEnd();
        
        //结果解析,异常情况判断
        JObject json = JObject.Parse(postContent);
        var gList = json["data"];
        if (json["status"] == null || gList == null || json["msg"] == null)
            error = "接口错误";
        else if (json["status"].ToString() != "success")
            error = string.Format("接口查询结果返回错误,{0}", json["msg"]);
        else if (gList.ToString() != string.Empty)
            result = gList["info"].ToString();
        else { }
    }
    catch (Exception ex)
    {
        error = ex.Message;
    }
    if (error != string.Empty)
        MessageBox.Show(error);

    return result;
}

1.2请求参数可以用表单数据(键值对)拼接时

url为请求的接口地址，pairs为请求的参数(字典格式)

private string GetUrlEncodeData(string url, Dictionary<string, string> pairs)
{
    string result = string.Empty;
    string error = string.Empty;
    try
    {
        StringBuilder sb = new StringBuilder();
        foreach (string key in pairs.Keys)
            sb.Append(key).Append("=").Append(pairs[key]).Append("&");
        if (pairs.Count > 0)
            url = url + "?" + sb.ToString().Trim('&');

        HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
        request.ContentType = "application/x-www-form-urlencoded"; //表单数据(键值对)
        request.Timeout = 20000;  //超时时间
        request.Method = "GET";  //请求方式
        request.KeepAlive = true; //解决GetResponse操作超时问题
        request.Headers.Add("Authorization", "token"); //如果接口需要鉴权, 把"token"换成自己需要的

        //通过HttpWebRequest的GetResponse()方法建立HttpWebResponse,强制类型转换
        HttpWebResponse response = (HttpWebResponse)request.GetResponse();
        //获取响应内容，返回的数据格式: {"status":"success","msg":"成功","data":{"info": "example"}}
        string postContent = new StreamReader(response.GetResponseStream()).ReadToEnd();
        
        //结果解析,异常情况判断
        JObject json = JObject.Parse(postContent);
        var gList = json["data"];
        if (json["status"] == null || gList == null || json["msg"] == null)
            error = "接口错误";
        else if (json["status"].ToString() != "success")
            error = string.Format("接口查询结果返回错误,{0}", json["msg"]);
        else if (gList.ToString() != string.Empty)
            result = gList["info"].ToString();
        else { }
    }
    catch (Exception ex)
    {
        error = ex.Message;
    }
    if (error != string.Empty)
        MessageBox.Show(error);

    return result;
}

2.POST请求方式

2.1请求参数为json字符串格式时

url为请求的接口地址，pairs为请求的参数(字典格式)

private string PostJsonData(string url, Dictionary<string, string> pairs)
{
    string result = string.Empty;
    string error = string.Empty;
    try
    {
        HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
        request.Timeout = 20000;  //超时时间
        request.Method = "POST";  //请求方式
        request.KeepAlive = true; //解决GetResponse操作超时问题
        request.Headers.Add("Authorization", "token"); //如果接口需要鉴权, 把"token"换成自己需要的

        //设置Content-type HTTP标头的值，即请求的媒体类型
        request.ContentType = "application/json"; //json字符串
        //request.ContentType = "multipart/form-data"; //多分部数据

        string content = JsonConvert.SerializeObject(pairs);
        byte[] data = Encoding.UTF8.GetBytes(content);
        //写入请求的参数
        using (var stream = request.GetRequestStream())
            stream.Write(data, 0, data.Length);

        //通过HttpWebRequest的GetResponse()方法建立HttpWebResponse,强制类型转换
        HttpWebResponse response = (HttpWebResponse)request.GetResponse();

        //获取响应内容，返回的postContent是json字符串格式:{"status":"success","msg":"成功","data":{"info": "example"}}
        string postContent = new StreamReader(response.GetResponseStream()).ReadToEnd();
        
        //结果解析,异常情况判断
        JObject json = JObject.Parse(postContent);
        var gList = json["data"];
        if (json["status"] == null || gList == null || json["msg"] == null)
            error = "接口错误";
        else if (json["status"].ToString() != "success")
            error = string.Format("接口查询结果返回错误,{0}", json["msg"]);
        else if (gList.ToString() != string.Empty)
            result = gList["info"].ToString();
        else { }
    }
    catch (Exception ex)
    {
        error = ex.Message;
    }
    if (error != string.Empty)
        MessageBox.Show(error);

    return result;
}

2.2请求参数为表单数据(键值对)格式时

url为请求的接口地址，pairs为请求的参数(字典格式)

private string PostUrlEncodeData(string url, Dictionary<string, string> pairs)
{
    string result = string.Empty;
    string error = string.Empty;
    try
    {
        HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
        request.ContentType = "application/x-www-form-urlencoded"; //表单数据(键值对)
        request.Timeout = 20000;  //超时时间
        request.Method = "POST";  //请求方式
        request.KeepAlive = true; //解决GetResponse操作超时问题
        request.Headers.Add("Authorization", "token"); //如果接口需要鉴权, 把"token"换成自己需要的

        StringBuilder sb = new StringBuilder();
        foreach (string key in pairs.Keys)
            sb.Append(key).Append("=").Append(pairs[key]).Append("&");
        string content = sb.ToString().Trim('&');
        byte[] data = Encoding.UTF8.GetBytes(content);

        //写入请求的参数
        using (var stream = request.GetRequestStream())
            stream.Write(data, 0, data.Length);

        //通过HttpWebRequest的GetResponse()方法建立HttpWebResponse,强制类型转换
        HttpWebResponse response = (HttpWebResponse)request.GetResponse();

        //获取响应内容，返回的json字符串postContent格式: 
        //{"status":"success","msg":"成功","data":{"info": "example"}}
        string postContent = new StreamReader(response.GetResponseStream()).ReadToEnd();
        
        //结果解析,异常情况判断
        JObject json = JObject.Parse(postContent);
        var gList = json["data"];
        if (json["status"] == null || gList == null || json["msg"] == null)
            error = "接口错误";
        else if (json["status"].ToString() != "success")
            error = string.Format("接口查询结果返回错误,{0}", json["msg"]);
        else if (gList.ToString() != string.Empty)
            result = gList["info"].ToString();
        else { }
    }
    catch (Exception ex)
    {
        error = ex.Message;
    }
    if (error != string.Empty)
        MessageBox.Show(error);

    return result;
}

2.3请求参数为多分部数据(复合式表单)格式时，(以上传文件接口为例)

url为请求的接口地址，filePath为文件的绝对路径。

首先获取本地文件路径，

string uploadURL = "http://127.0.0.1:8888/api/test/";
string uploadFilePath = string.Empty;

OpenFileDialog openFileDialog = new OpenFileDialog
{
    Filter = "所有文件|*.*"
};
if (openFileDialog.ShowDialog() == DialogResult.OK)
    uploadFilePath = openFileDialog.FileName;

string result = PostMultipartData(uploadURL, uploadFilePath);

上传文件函数文章来源地址https://www.toymoban.com/news/detail-400462.html

private string PostMultipartData(string url, string filePath)
{
    string result = string.Empty;
    string error = string.Empty;
    try
    {
        HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);

        request.Timeout = 20000;  //超时时间
        request.Method = "POST";  //请求方式
        request.KeepAlive = true; //解决GetResponse操作超时问题
        request.ContentType = "multipart/form-data"; //多分部数据(复合式表单)
        request.Headers.Add("Authorization", "token"); //如果接口需要鉴权, 把"token"换成自己需要的
        
        //读取文件内容
        FileStream fs = new FileStream(filePath, FileMode.Open, FileAccess.Read);
        byte[] fileData = new byte[fs.Length];
        fs.Read(fileData, 0, fileData.Length);

        string fileName = Path.GetFileName(filePath);

        //浏览器在发送表单的enctype="multipart/form-data", 需要在往后台发送请求的时候添加一个[boundary]属性
        string boundary = "test" + DateTime.Now.Ticks.ToString("x");  // 边界符, "test"可以改, 其他部分不能改
        byte[] boundarybytes = Encoding.UTF8.GetBytes("\r\n--" + boundary + "\r\n");  // 边界符开始
        byte[] endbytes = Encoding.UTF8.GetBytes("\r\n--" + boundary + "--\r\n");  // 边界符结束

        //写入请求的参数
        using (var stream = request.GetRequestStream())
        {
            //获取文件头的字节序列
            string temp = "Content-Disposition: form-data; name=\"{0}\"; filename=\"{1}\"\r\n";
            string header = string.Format(temp, "file", fileName);
            byte[] fileHeader = Encoding.UTF8.GetBytes(header);

            stream.Write(boundarybytes, 0, boundarybytes.Length); //写入FormData项的开始边界符
            stream.Write(fileHeader, 0, fileHeader.Length); //将文件头写入FormData项中

            stream.Write(boundarybytes, 0, boundarybytes.Length); //每两次写入之间要加入开始边界符
            stream.Write(fileData, 0, fileData.Length);  //将文件流写入FormData项
            stream.Write(endbytes, 0, endbytes.Length);  //写入FormData的结束边界符
        }

        //通过HttpWebRequest的GetResponse()方法建立HttpWebResponse,强制类型转换
        HttpWebResponse response = (HttpWebResponse)request.GetResponse();

        //获取响应内容，返回的json字符串postContent格式: 
        //{"status":"success","msg":"成功","data":{"info": "example"}}
        string postContent = new StreamReader(response.GetResponseStream()).ReadToEnd();

        //结果解析,异常情况判断
        JObject json = JObject.Parse(postContent);
        var gList = json["data"];
        if (json["status"] == null || gList == null || json["msg"] == null)
            error = "接口错误";
        else if (json["status"].ToString() != "success")
            error = string.Format("接口查询结果返回错误,{0}", json["msg"]);
        else if (gList.ToString() != string.Empty)
            result = gList["info"].ToString();
        else { }
    }
    catch (Exception ex)
    {
        error = ex.Message;
    }
    if (error != string.Empty)
        MessageBox.Show(error);

    return result;
}

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