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如何从id获取二维码?

thymeleaf qr-code spring

-1

Marcio · 技术社区 · 9 年前

在我的控制器中,我有以下方法:

import net.glxn.qrgen.QRCode;
import org.marcio.demospringboot.dao.FormationRepository;
import org.marcio.demospringboot.model.Formation;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.ui.ModelMap;
import org.springframework.web.bind.annotation.*;
import java.io.ByteArrayOutputStream;
import java.util.Map;

@Controller
public class FormationController {

@Autowired
private FormationRepository formationRepository;

@RequestMapping (value="formation/qr/{id}", method = RequestMethod.GET)
public ResponseEntity<byte[]> qr(@PathVariable final Long id) {

    ByteArrayOutputStream stream = QRCode.from(formationRepository.findOne(id).toString()).stream();

    byte[] bytes = stream.toByteArray();

    final HttpHeaders headers = new HttpHeaders();
    headers.setContentType(MediaType.IMAGE_PNG);

    return new ResponseEntity<byte[]> (bytes, headers, HttpStatus.CREATED);
}
}

在我的html页面中:

<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org">
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
    <title>QR Code</title>
</head>
<body>

   <img th:src="@{/formation/qr/${id}}" />

</body>
</html>

这是生成的图像:

我想从你的“id”中获取用户数据。我使用的是一个简单的存储库Spring formationRepository 和图书馆 net.glxn.qrgen.QRCode 。该应用程序可以工作,但不会使用有关“id”的用户数据生成二维码。谢谢

2 回复 | 直到 9 年前

Aviad 9 年前

忘记“/” @RequestMapping (value="/formation/qr/{id}", method = RequestMethod.GET) 形成前

编辑:

ByteArrayOutputStream stream = QRCode.from(formationRepository.findOne(id).toString()).stream();
byte[] data = stream.toByteArray();;
HttpHeaders headers = new HttpHeaders();
headers.setContentType(MediaType.IMAGE_JPEG);
headers.setContentLength(data.length);

return new HttpEntity<byte[]>(data, headers);

这应该可以正常工作,这样浏览器就会理解它是一个图像并显示它

Marcio 9 年前

感谢您的帮助和评论。他们都很乐于助人。我可以通过升级到以下位置来解决问题:

@RequestMapping (value="/formation/qr/{id}", method = RequestMethod.GET)
public HttpEntity<byte[]> qr(@PathVariable Long id) {
    byte[] bytes = QRCode.from(formationRepository.findOne(id).getTheme()
                   .toString()).withSize(120, 120).stream().toByteArray();
    final HttpHeaders headers = new HttpHeaders();
    headers.setContentType(MediaType.IMAGE_PNG);
    headers.setContentLength(bytes.length);
    return new ResponseEntity<byte[]> (bytes, headers, HttpStatus.CREATED); 
}

解决方案是 byte []bytes = QRCode.from(formation Repository.findOne (id).getTheme() 。所以我得到了注册内容(getTheme),并以二维码呈现。