基础知识 java 图片与string相互转换

import sun.misc.BASE64Decoder;

import java.awt.*;
import java.awt.image.BufferedImage;
import java.awt.image.RenderedImage;
import java.io.*;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.Base64;
import javax.imageio.ImageIO;
import javax.swing.*;

public class Main {

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

BufferedImage image_buffer = ImageIO.read(new File("D:\\1.jpg"));
String string_image=imgToBase64String(image_buffer);

FileWriter fi = new FileWriter("D:\\1.txt");
fi.write(string_image);
fi.close();

String content = new String(Files.readAllBytes(Paths.get("D:\\1.txt")));
BufferedImage new_image_buffer=base64StringToImg(content);
draw_image(new_image_buffer);

}

//把图片转换成string类型
public static String imgToBase64String(final RenderedImage img) {
final ByteArrayOutputStream os = new ByteArrayOutputStream();
try {
ImageIO.write(img, "jpg", Base64.getEncoder().wrap(os));
return os.toString(StandardCharsets.ISO_8859_1.name());
} catch (final IOException ioe) {
throw new UncheckedIOException(ioe);
}
}
//把string类型转换成图片
public static BufferedImage base64StringToImg(final String base64String) {
try {
BASE64Decoder decoder = new BASE64Decoder();
byte[] bytes = decoder.decodeBuffer(base64String);
ByteArrayInputStream bais = new ByteArrayInputStream(bytes);
return ImageIO.read(bais);
} catch (final IOException ioe) {
throw new UncheckedIOException(ioe);
}
}

//绘制图片
public static  void draw_image(BufferedImage image_buffer) throws IOException {
ImageIcon icon = new ImageIcon(image_buffer);
JFrame frame = new JFrame();
frame.setLayout(new FlowLayout());

frame.setSize(image_buffer.getWidth(), image_buffer.getHeight());
JLabel lbl = new JLabel();
lbl.setIcon(icon);
frame.add(lbl);
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

}

}