Question

我已经创建了一个如下所示的servlet：

def tqdm_redirect(*args, **kwargs):
    with redirect_to_tqdm():
        for x in tqdm.tqdm(*args, **kwargs):
            yield x

for i in tqdm_redirect(range(20)):
    time.sleep(.1)
    print(i)

由于图像是动态生成的（即解密的），我无法将其保存为文件系统中的文件。所以我使用import java.awt.image.BufferedImage; import java.io.File; import java.io.IOException; import java.io.OutputStream; import java.io.PrintWriter; import javax.imageio.ImageIO; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; public class otpcheck extends HttpServlet { /** * Handles the HTTP <code>POST</code> method. * * @param request servlet request * @param response servlet response * @throws ServletException if a servlet-specific error occurs * @throws IOException if an I/O error occurs */ @Override protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { PrintWriter out =response.getWriter(); Crypting c=new Crypting(); BufferedImage imgKey; BufferedImage imgEnc; imgKey = ImageIO.read(new File("E:/Key.png")); imgEnc=ImageIO.read(new File("E:/E.png")); response.setContentType("text/html"); out.println( "<!DOCTYPE html>\n" + "<html>\n" + " <head>\n" + " \n" + " <title>Online Banking</title>\n" + " \n" + " <link rel=\"stylesheet\" href=\"newcss.css\">\n" + " </head>\n" + "<!DOCTYPE html>\n" + "\n" + " <div class=\"wrapper\">\n" + " \n" + " <div class=\"header\">\n" + " <img src=\"header_1.jpg\" height=\"100%\" width=\"100%\"/>\n" + " </div>\n" + " <div class=\"navbar\">\n" + " \n" + " <ul>\n" + " <li><a href=\"index.jsp\">Home</a></li>\n" + " <li><a href=\"features.jsp\">Features</a></li>\n" + " <li id=\"last\"><a href=\"contact.jsp\">Contact Us</a></li>\n" + " </ul>\n" + " </div>" + "\n" + "<div class='content'>\n" + "<div class=\"user_login\">"); out.println("<p>Scan the QR Image to get OTP</p>"); BufferedImage imgDec=Crypting.decryptImage(imgKey,imgEnc); response.setContentType("image/png"); OutputStream os=response.getOutputStream(); ImageIO.write(imgDec,"png",os); out.println("<form action=\"otpvalidate\" method=\"POST\" enctype=\"multipart / form - data\">Enter OTP:<input type=\"password\" name=\"otp\"/>\n<input type=\"submit\" value=\"SUBMIT\" name=\"submit\" /></form >"); out.println("</div>\n" + "</div>\n" + "<!DOCTYPE html>\n" + " <meta http-equiv=\"Content-Type\" content=\"text/html; charset=UTF- 8\">\n" + " <div class=\"footer\">\n" + "<ul>\n" + " \n" + " <div class=\"footer_content\">\n" + " <li><a href=\"features.jsp\">Features </a></li>\n" + " <li><a href=\"contact.jsp\"> Contact</a></li>\n" + " \n" + " <li><a href=\"safeonlinebanking.jsp\">Safe online Banking tips</a></li>\n" + " \n" + " <li style=\"padding-left:450px;\">Copyright©2017 onlinebanking.com</li>\n" + " \n" + " </div>\n" + " </ul> \n" + " \n" + " \n" + " \n" + " </div>\n" + " </div> \n" + " </body>\n" + "</html>\n" + "\n" + "</html>"); } }和OutputStream来显示图像。但是我还需要使用html生成一个输入和按钮。所以我使用了另一个response.setContentType("image/png")来显示html。

我的问题是我收到的错误是response.setContentType("text/html")。所以内容类型的响应相互冲突。

请帮我解决这个错误!!!

Answer 1

在HTTP协议中，您可以访问资源。每种资源都有自己的类型。

在您的示例中，您至少有3个资源，一个用于HTML页面，一个用于key.png，另一个用于e.png

怎么办？

您可以让您的servlet仅为您的HTML页面提供服务，并且在HTML页面中您可以将图像标记指向图像的资源

<html>
...
<img src="http://miserver/key.png">
<img src="http://miserver/e.png">

对于图像，您可以将它们放在war文件中，服务器提供图像。

但是如果您的图像像数据库一样存储在战争之外，您可以创建其他服务于您图像的servlet。在IMG标记的SRC属性中，放置该servlet的URL。

Answer 2

首先，谢谢大家的贡献。我找到了答案及其工作。

我创建了一个servlet来返回图像。然后我创建了一个jsp文件，通过将URL设置为<img src="${pageContext.request.contextPath}/otpcheck" />来获取该图像。而且它的工作性很好。这是代码。

import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.io.OutputStream;
import java.io.PrintWriter;
import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class otpcheck extends HttpServlet {



@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response)
        throws ServletException, IOException {


    Crypting c=new Crypting();
    BufferedImage imgKey;
    BufferedImage imgEnc;
    imgKey = ImageIO.read(new File("E:/Key.png"));
    imgEnc=ImageIO.read(new File("E:/upload/E.png"));
     BufferedImage imgDec=Crypting.decryptImage(imgKey,imgEnc);
    response.setContentType("image/png");
    OutputStream os=response.getOutputStream();
    ImageIO.write(imgDec,"png",os);
}
}

jsp如下：

<img src="${pageContext.request.contextPath}/otpcheck" />
    <form action="otpvalidate" method="POST" enctype="multipart/form-data">
        Enter OTP:<input type="password" name="otp"/><input type="submit" value="SUBMIT" name="submit" />
    </form>

我提到了BalusC给出的一些答案。这就是我如何使用代码。

是否可以在单个servlet中使用两种内容类型？

2 个答案: