java base64转图片png格式

Java中可以使用Base64类将base64格式的字符串转换为图片。具体步骤如下：
1. 将base64字符串解码为字节数组。
2. 使用ImageIO类的read方法将字节数组转换为BufferedImage对象。
3. 将BufferedImage对象保存为png格式的图片文件。

以下是一个示例代码：

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Base64;

import javax.imageio.ImageIO;

public class Base64ToImage {
    public static void main(String[] args) throws IOException {
        String base64String = "iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAYAAAAf8/9hAAACW0lEQVR4nLWTT0jTURzHv7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7MzO7M