base64图片格式转换为file

import org.apache.commons.codec.binary.Base64;
public static MultipartFile base64ToMultipartFile(String base64) {
    
    
		String img="data:image/png;base64,"+base64;
		//base64编码后的图片有头信息所以要分离出来 [0]data:image/png;base64, 图片内容为索引[1]
		String[] baseStrs = img.split(",");
		//取索引为1的元素进行处理
		byte[] b = Base64.decodeBase64(baseStrs[1]);
		for (int i = 0; i < b.length; ++i) {
    
    
			if (b[i] < 0) {
    
    
				b[i] += 256;
			}
		}
		//处理过后的数据通过Base64DecodeMultipartFile转换为MultipartFile对象
		return new BASE64DecodedMultipartFile(b, baseStrs[0]);
	}

import org.springframework.web.multipart.MultipartFile;

import java.io.*;

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);
	}

}