Java将base64字符串转成MultipartFile类型

旧城等待， 2022-12-07 15:06 456阅读 0赞

# 一、写一个base64转multipartfile工具类BASE64DecodedMultipartFile，注意实现MultipartFile接口 #

package com.doctor.cloud.mobile.web.utils;
    
    /** * @Author: zxb * @Date: 2020/9/15 14:11 * @Version: 1.0 * @Description: base64转multipartfile工具类 **/
    
    import org.springframework.web.multipart.MultipartFile;
    import sun.misc.BASE64Decoder;
    
    import java.io.*;
    
    /** * base64转MultipartFile */
    public class BASE64DecodedMultipartFile implements MultipartFile { 
    
        private final byte[] imgContent;
        private final String header;
    
        public BASE64DecodedMultipartFile(byte[] imgContent, String header) { 
            this.imgContent = imgContent;
            this.header = header.split(";")[0];
        }
    
        @Override
        public String getName() { 
            return System.currentTimeMillis() + Math.random() + "." + header.split("/")[1];
        }
    
        @Override
        public String getOriginalFilename() { 
            return System.currentTimeMillis() + (int) Math.random() * 10000 + "." + header.split("/")[1];
        }
    
        @Override
        public String getContentType() { 
            return header.split(":")[1];
        }
    
        @Override
        public boolean isEmpty() { 
            return imgContent == null || imgContent.length == 0;
        }
    
        @Override
        public long getSize() { 
            return imgContent.length;
        }
    
        @Override
        public byte[] getBytes() throws IOException { 
            return imgContent;
        }
    
        @Override
        public InputStream getInputStream() throws IOException { 
            return new ByteArrayInputStream(imgContent);
        }
    
        @Override
        public void transferTo(File dest) throws IOException, IllegalStateException { 
            new FileOutputStream(dest).write(imgContent);
        }
    
        public static MultipartFile base64ToMultipart(String base64) { 
            try { 
                String[] baseStrs = base64.split(",");
    
                BASE64Decoder decoder = new BASE64Decoder();
                byte[] b = new byte[0];
                b = decoder.decodeBuffer(baseStrs[1]);
    
                for (int i = 0; i < b.length; ++i) { 
                    if (b[i] < 0) { 
                        b[i] += 256;
                    }
                }
                return new BASE64DecodedMultipartFile(b, baseStrs[0]);
            } catch (IOException e) { 
                e.printStackTrace();
                return null;
            }
        }
    
    }

# 二、调用方式 #

MultipartFile multipartFile = BASE64DecodedMultipartFile.base64ToMultipart(base64);