直接上代码，可以直接运行。唯一需要注意的是sun.misc.BASE64Decoder 这个包可能无法引入。可以参考这个博客设置

https://blog.csdn.net/erlian1992/article/details/79518416

import java.io.File;

import java.io.FileOutputStream;

import java.io.IOException;

import java.io.OutputStream;

import java.text.SimpleDateFormat;

import java.util.Date;

import java.util.UUID;

import java.util.regex.Matcher;

import java.util.regex.Pattern;

import sun.misc.BASE64Decoder;

import com.sun.org.apache.xml.internal.security.exceptions.Base64DecodingException;

import com.sun.org.apache.xml.internal.security.utils.Base64;

public class Test3 {

// 图片路劲层级分隔符

private static String separator = "/";

public static void main(String[] args) throws Base64DecodingException {

Test3 t = new Test3();

//在这里可以直接写入base64的值进行测试

String path = t.saveImg("");

//输出路径

System.out.println(path);

}

public String saveImg(String baseImg) throws Base64DecodingException {

//定义一个正则表达式的筛选规则，为了获取图片的类型

String rgex = "data:image/(.*?);base64";

String type = getSubUtilSimple(baseImg, rgex);

//去除base64图片的前缀

baseImg = baseImg.replaceFirst("data:(.+?);base64,", "");

byte[] b;

byte[] bs;

OutputStream os = null;

String fileName = "";

String nowDate = "";

// 格式化并获取当前日期(用来命名)

SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd");

nowDate = format.format(new Date());

//把图片转换成二进制

b = Base64.decode(baseImg.replaceAll(" ", "+"));

//生成路径

String path = "D:/home/upload/" + separator + "img" + separator + nowDate + separator;

//随机生成图片的名字，同时根据类型结尾

fileName = UUID.randomUUID().toString() + "." + type;

File file = new File(path);

if (!file.exists() && !file.isDirectory()) {

file.mkdirs();

}

File imageFile = new File(path + "/" + fileName);

BASE64Decoder d = new BASE64Decoder();

// 保存

try {

bs = d.decodeBuffer(Base64.encode(b));

os = new FileOutputStream(imageFile);

os.write(bs);

} catch (IOException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}finally {

if (os != null) {

try {

os.close();

} catch (IOException e) {

e.getLocalizedMessage();

}

}

}

return "img" + separator + nowDate + separator + fileName;

}

public static String getSubUtilSimple(String soap,String rgex){

Pattern pattern = Pattern.compile(rgex);

Matcher m = pattern.matcher(soap);

while(m.find()){

return m.group(1);

}

return "";

}

}