spring 如何使用spring将编码的base64图像上传到服务器

How to upload encoded base64 image to the server using spring

提问by srihari

I'm writing a webservice using spring.
This service takes the base64 encoded image as a String parameter.
I want to decode this String into image and upload into server.

我正在使用 spring 编写一个网络服务。
此服务将 base64 编码的图像作为 String 参数。
我想将此字符串解码为图像并上传到服务器。

@RequestMapping(value="/uploadImage",method = RequestMethod.POST)
public @ResponseBody String uploadImage(@RequestParam("encodedImage") String encodedImage)
{
    byte[] imageByte= Base64.decodeBase64(encodedImage);
    return null;
}

采纳答案by srihari

The below code is used to decode the string which is encoded by using base 64 and used to upload image into the server.

下面的代码用于解码使用base 64编码的字符串并用于将图像上传到服务器。

This working fine for me..

这对我来说很好用..

@RequestMapping(value="/uploadImage2",method = RequestMethod.POST)
    public @ResponseBody String uploadImage2(@RequestParam("imageValue") String imageValue,HttpServletRequest request)
    {
        try
        {
            //This will decode the String which is encoded by using Base64 class
            byte[] imageByte=Base64.decodeBase64(imageValue);

            String directory=servletContext.getRealPath("/")+"images/sample.jpg";

            new FileOutputStream(directory).write(imageByte);
            return "success ";
        }
        catch(Exception e)
        {
            return "error = "+e;
        }

    }

回答by Robby Cornelissen

Use Java's Base64.Decoderto decode the string to a byte array.

使用 JavaBase64.Decoder将字符串解码为字节数组。

If that's not available in your version of Java, you can use the same functionality from the Apache Commons Codecproject.

如果您的 Java 版本中没有该功能，您可以使用Apache Commons Codec项目中的相同功能。

回答by John Deverall

If you're using Spring you could consider using an HttpMessageConverter to convert your image to a BufferedImage before it reaches your controllers. I couldn't find an already made one in the spring converters (maybe I missed it?). In any case this is something I just wrote now. You may be able to improve it.

如果您使用的是 Spring，则可以考虑使用 HttpMessageConverter 在图像到达控制器之前将其转换为 BufferedImage。我在弹簧转换器中找不到已经制作好的一个（也许我错过了？）。无论如何，这是我现在刚刚写的东西。你也许可以改进它。

 package com.stuff;

    import java.awt.image.BufferedImage;
    import java.io.ByteArrayInputStream;
    import java.io.IOException;
    import java.io.StringWriter;
    import java.util.ArrayList;
    import java.util.List;

    import javax.imageio.ImageIO;

    import org.apache.commons.codec.binary.Base64;
    import org.apache.commons.io.IOUtils;
    import org.apache.log4j.Logger;
    import org.springframework.http.HttpInputMessage;
    import org.springframework.http.HttpOutputMessage;
    import org.springframework.http.MediaType;
    import org.springframework.http.converter.AbstractHttpMessageConverter;
    import org.springframework.http.converter.HttpMessageNotReadableException;
    import org.springframework.http.converter.HttpMessageNotWritableException;

    /**
     * @author John Deverall
     */
    public class Base64EncodedImageHttpMessageConverter extends
            AbstractHttpMessageConverter<BufferedImage> {

        private Logger logger = Logger.getLogger(this.getClass());

        public Base64EncodedImageHttpMessageConverter() {

            List<MediaType> mediaTypes = new ArrayList<MediaType>();
            String[] supportedMediaTypes = ImageIO.getReaderMIMETypes();
            for (String supportedMediaType : supportedMediaTypes) {
                String[] typeAndSubtype = supportedMediaType.split("/");
                mediaTypes.add(new MediaType(typeAndSubtype[0], typeAndSubtype[1]));
            }

            setSupportedMediaTypes(mediaTypes);   
        }

        @Override
        protected boolean supports(Class<?> clazz) {
            return clazz.equals(BufferedImage.class);
        }

        /** This uses a data uri. If that's not you, 
         * you'll need to modify this method to decode the base64 data
         * straight. */
        @Override
        protected BufferedImage readInternal(Class<? extends BufferedImage> clazz,
                HttpInputMessage inputMessage) throws IOException,
                HttpMessageNotReadableException {

            StringWriter writer = new StringWriter();
            IOUtils.copy(inputMessage.getBody(), writer, "UTF-8");
            String imageInBase64 = writer.toString();
            int startOfBase64Data = imageInBase64.indexOf(",") + 1;
            imageInBase64 = imageInBase64.substring(startOfBase64Data,
                    imageInBase64.length());

            if (Base64.isBase64(imageInBase64) == false) {
                logger.error("************************************************");
                logger.error("*** IMAGE IN REQUEST IS NOT IN BASE64 FORMAT ***");
                logger.error("************************************************");
            }

            byte[] decodeBase64 = Base64.decodeBase64(imageInBase64);
            BufferedImage image = ImageIO.read(new ByteArrayInputStream(
                    decodeBase64));
            return image;

        }     

    @Override
    protected void writeInternal(BufferedImage t,
                HttpOutputMessage outputMessage) throws IOException,
                HttpMessageNotWritableException {
            ImageIO.write(t, "jpeg", outputMessage.getBody());
            outputMessage.getBody().flush();
        }

    }

Then in your controller, write something like this (or preferably pass the BufferedImage to some kind of service). Notice that the conversion logic from base64 to the BufferedImage is reusable and hidden in the HttpMessageConverter.

然后在您的控制器中，编写类似的内容（或者最好将 BufferedImage 传递给某种服务）。请注意，从 base64 到 BufferedImage 的转换逻辑是可重用的，并且隐藏在 HttpMessageConverter 中。

@RequestMapping(value = "/image", method = RequestMethod.POST)
    public @ResponseBody void saveImage(@PathVariable String memberId, @RequestBody BufferedImage image)  {     
        someService.setBufferedImage(image);
    }



@RequestMapping(produces = MediaType.IMAGE_JPEG_VALUE, value = "/image", method = RequestMethod.GET)
    public @ResponseBody BufferedImage getImage() { 
        BufferedImage image = someService.getBufferedImage();
        return image;
    }

If you're using spring's java configuration, configuration of HttpMessageConverters looks something like this

如果您使用的是 spring 的 java 配置，则 HttpMessageConverters 的配置看起来像这样

    @Configuration
    @EnableWebMvc
    public class ApplicationConfig extends WebMvcConfigurerAdapter {

    @Override
        public void configureMessageConverters(
                List<HttpMessageConverter<?>> converters) {
            converters.add(getJsonConverter());
            converters.add(getImageConverter());
            super.configureMessageConverters(converters);
        }

        @Bean
        GsonHttpMessageConverter getJsonConverter() { 
            GsonHttpMessageConverter converter = new GsonHttpMessageConverter();
            return converter;
        }

        @Bean
        Base64EncodedImageHttpMessageConverter getImageConverter() { 
            Base64EncodedImageHttpMessageConverter converter = new Base64EncodedImageHttpMessageConverter();
            return converter;
        }

}

If you like, you could avoid using apache commons if you don't need it and just go with the new java8 java.util.base64 class. The GsonHttpMessageConverter (for converting Json to my domain objects) is not used for images either so you can pull that out of the config if images is all you're doing.

如果你愿意，如果你不需要它，你可以避免使用 apache commons，只需使用新的 java8 java.util.base64 类。GsonHttpMessageConverter（用于将 Json 转换为我的域对象）也不用于图像，因此如果图像就是您所做的一切，您可以将其从配置中拉出。

回答by ArunDhwaj IIITH

Following is working for me:

以下对我有用：

package com.SmartBitPixel.XYZ.pqr.Controllers;

import java.util.Base64;    
import java.io.BufferedOutputStream;    
import java.io.File;    
import java.io.FileOutputStream;    
import java.util.Base64;    
import java.util.List;    
import java.util.Locale;    
import javax.servlet.http.HttpServletRequest;    
import org.slf4j.Logger;    
import org.slf4j.LoggerFactory;    
import org.springframework.beans.factory.annotation.Autowired;    
import org.springframework.beans.factory.annotation.Qualifier;    
import org.springframework.stereotype.Controller;    
import org.springframework.ui.Model;    
import org.springframework.web.bind.annotation.ModelAttribute;    
import org.springframework.web.bind.annotation.PathVariable;    
import org.springframework.web.bind.annotation.RequestMapping;    
import org.springframework.web.bind.annotation.RequestMethod;    
import org.springframework.web.bind.annotation.RequestParam;    
import org.springframework.web.multipart.MultipartFile;    

@Controller    
public class MainDocController     
{    
  @RequestMapping(value="/ProfileRegSubmit", method=RequestMethod.POST)
    public String handleFileUpload( 
            @RequestParam("fName") String fName, @RequestParam("lName") String lName,
            @RequestParam("imgName") String imgName, @RequestParam("webcamScanImage") String scanImageFile )
    {       

        if (!scanImageFile.isEmpty()) 
        {
            try 
            {               
                byte[] scanBytes = Base64.getDecoder().decode(scanImageFile);


                                ///////////////////////////////////////////////////////////////
                // Creating the directory to store file/data/image ////////////

                String rootPath = System.getProperty("catalina.home");

                File fileSaveDir = new File(rootPath + File.separator + SAVE_DIR);

                // Creates the save directory if it does not exists
                if (!fileSaveDir.exists()) 
                {
                    fileSaveDir.mkdirs();
                }

                File scanFile = new File( fileSaveDir.getAbsolutePath() + File.separator + "scanImageFile.png");
                BufferedOutputStream scanStream = new BufferedOutputStream( new FileOutputStream( scanFile ) );       
                scanStream.write(scanBytes);
                scanStream.close();

                returnStr = "RegisterSuccessful";

            }
            catch (Exception e) 
            {
                returnStr = "You failed to upload scanImageFile => " + e.getMessage();
            }
        }
        else 
        {
            returnStr = "You failed to upload scanImageFile because the file is empty.";
        }
    }
}