1.路徑

<img src="balabala/123.jpg">

2.img標籤指向servlet方法

<img src="/ImgServlet?imgId=00001" alt="picture">

主要流程為：獲取id—>查詢資料庫得到圖片路徑—>重置response—>得到輸出流—>設定contenttype—>讀取檔案流—>輸入快取區—>輸出快取區—>緩衝位元組數

protected void doPost(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException {
       String imgId = request.getParameter("imgId");
       String imagePath = getImagePathFromDB(imgId);

       response.reset();
       OutputStream output = response.getOutputStream();
    response.setContentType(GIF);
    ServletContext context = getServletContext();
    InputStream imageIn = context.getResourceAsStream(imagePath);
    BufferedInputStream bis = new BufferedInputStream(imageIn);
    BufferedOutputStream bos = new BufferedOutputStream(output);
    byte data[] = new byte[4096];
    int size = 0;
    size = bis.read(data);
    while (size != -1) {
        bos.write(data, 0, size);
        size = bis.read(data);
    }

    bis.close();
    bos.flush();
    bos.close();
    output.close();
}       
 

3.二進位制流顯示圖片（不存到本地）

將圖片轉換成資料流，然後將資料流一對一將傳進轉化為陣列的MemoryStream中，通過image控制元件顯示圖片

string path = "https://img3.doubanio.com/mpic/s8896281.jpg";
            Uri url = new Uri(path);
            WebRequest webRequest = WebRequest.Create(url);
            WebResponse webResponse = webRequest.GetResponse();
            Bitmap myImage = new Bitmap(webResponse.GetResponseStream());

            MemoryStream ms = new MemoryStream();
            myImage.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);
            var p = new pictureUrl
            {
                pictureUrl1 = ms.ToArray()
            };
            db.pictureUrl.InsertOnSubmit(p);
            db.SubmitChanges();
 

var pictures = from picture in db.pictureUrl select picture;
            pictureUrl myPicture = pictures.First();
            MemoryStream mymemorystream = new MemoryStream(myPicture.pictureUrl1.ToArray());
            pictureBox1.Image = Image.FromStream(mymemorystream);

4.圖片轉化為base64字串

將圖片轉化為位元組字串陣列，並對其進行編碼處理，再解碼生成圖片

http://blog.sina.com.cn/s/blog_6400e5c50101qtr3.html

https://blog.csdn.net/hanchao5272/article/details/79261312

http://www.cnblogs.com/JsonZhangAA/p/5568575.html

http://www.cnblogs.com/JsonZhangAA/p/5574685.html