本文要演示的是使用Android程序作为客户端（使用HttpURLConnection访问网络），Golang程序作为服务器端，实现文件上传。

客户端代码：

public static String uploadFile(String uploadUrl,String filePath) {
        Log.v(TAG,"url:" + uploadUrl);
        Log.v(TAG,"filePath:" + filePath);

        String nextLine = "\r\n";
        String dividerStart = "--";
        String boundary = "******";
        try {
            URL url = new URL(uploadUrl);
            HttpURLConnection connection = (HttpURLConnection) url.openConnection();
            connection.setChunkedStreamingMode(1024 * 256);
            connection.setDoInput(true);
            connection.setDoOutput(true);
            connection.setUseCaches(false);
            connection.setRequestMethod("POST");
            // 设置Http请求头
            connection.setRequestProperty("Connection","Keep-Alive");
            connection.setRequestProperty("Charset","UTF-8");
            //必须在Content-Type 请求头中指定分界符
            connection.setRequestProperty("Content-Type","multipart/form-data;boundary=" + boundary);

            //定义数据写入流，准备上传文件
            DataOutputStream dos = new DataOutputStream(connection.getOutputStream());
            dos.writeBytes(dividerStart + boundary + nextLine);
            //设置与上传文件相关的信息
            dos.writeBytes("Content-Disposition: form-data; name=\"file\"; filename=\""
                    + filePath.substring(filePath.lastIndexOf("/") + 1) + "\"" + nextLine);
            dos.writeBytes(nextLine);

            FileInputStream fis = new FileInputStream(filePath);
            byte[] buffer = new byte[1024 * 32];
            int count;
            // 读取文件内容，并写入OutputStream对象
            while ((count = fis.read(buffer)) != -1) {
                dos.write(buffer,count);
            }
            fis.close();
            dos.writeBytes(nextLine);
            dos.writeBytes(dividerStart + boundary + dividerStart + nextLine);
            dos.flush();

            // 开始读取从服务器传过来的信息
            InputStream is = connection.getInputStream();
            BufferedReader br = new BufferedReader(new InputStreamReader(is,"UTF-8"));
            String result = br.readLine();

            dos.close();
            is.close();
            connection.disconnect();

            return result;
        } catch (IOException e) {
            e.printStackTrace();
        }

        return null;
    }

package webserver

//接收客户端通过http上传的文件
//Date: 2015-3-25 16:18:33

import (
	"fmt"
	"io/IoUtil"
	"log"
	"net/http"
	"os"
)

func UpLoadBase() {
	fmt.Println("This is uploadbase")
	http.HandleFunc("/httpUploadFile",handleUploadFile)
	http.ListenAndServe(":8086",nil)

	if err != nil {
		fmt.Println("ListenAndServe error: ",err.Error())
	}
}

func handleUploadFile(w http.ResponseWriter,r *http.Request) {
	fmt.Println("client:",r.RemoteAddr)

	file,fileHeader,err := r.FormFile("file")
	if err != nil {
		log.Fatal("FormFile:",err.Error())
		return
	}
	defer func() {
		if err := file.Close(); err != nil {
			log.Fatal("Close:",err.Error())
			return
		}
	}()

      
	//文件名
	fileName := fileHeader.Filename
	if fileName == "" {
		log.Fatal("Param filename cannot be null.")
		return
	}
	//文件内容
	bytes,err := IoUtil.ReadAll(file)

	//写到服务端本地文件中
	outputFilePath := "/home/admin/桌面/" + fileName
	err = IoUtil.WriteFile(outputFilePath,bytes,os.ModePerm)
	if err != nil {
		log.Fatal("WriteFileError:",err.Error())
		return
	}

	w.Write(([]byte)("上传文件成功！"))
}