java中快速讀寫圖片到BufferedImage對象

java7讀取文件到BufferedImage對象

BufferedImage bufferedImage = ImageIO.read(Files.newInputStream(Paths.get(basePath + imageSource)));

java7寫入文件到圖片對象

ImageIO.write(bufferedImage, "jpg", Files.newOutputStream(Paths.get(fullPath)));

The call to Files.newInputStream will return a ChannelInputStream which (AFAIK) is not buffered. You'll want to wrap it

new BufferedInputStream(Files.newInputStream(...));

So that there are less IO calls to disk, depending on how you use it.

意譯：據我所知,調用Files.newInputStream將會返回一些ChannelInputStream對象。如果你想對他進行封裝，使用以下代碼
new BufferedInputStream(File.newInputStream(Paths.get(fullPath)));
如此一來，磁盤IO的調用頻次將會降低，具體看你怎么用了。

 工具類：

import lombok.extern.slf4j.Slf4j;
import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;

import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.io.BufferedInputStream;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Paths;


@Slf4j
public final class GraphUtil {

    /**
     * Encode Image to Base64 String
     * @param image
     * @param type
     * @return
     */
    public static String encodeToString(BufferedImage image, String type) {

        String imageString = null;
        ByteArrayOutputStream bos = new ByteArrayOutputStream();

        try {
            ImageIO.write(image, type, bos);
            byte[] imageBytes = bos.toByteArray();

            BASE64Encoder encoder = new BASE64Encoder();
            imageString = encoder.encode(imageBytes);

            bos.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return imageString;
    }


    /***
     * Decode Base64 String to Image
     * @param imageString
     * @return
     */
    public static BufferedImage decodeToImage(String imageString) {

        BufferedImage image = null;
        byte[] imageByte;
        try {
            BASE64Decoder decoder = new BASE64Decoder();
            imageByte = decoder.decodeBuffer(imageString);
            ByteArrayInputStream bis = new ByteArrayInputStream(imageByte);
            image = ImageIO.read(bis);
            bis.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
        return image;
    }

    public static BufferedImage getBufferedImage(String basePath, String imageSource){

        try {
            return ImageIO.read(new BufferedInputStream(Files.newInputStream(Paths.get(basePath, imageSource))));
        } catch (IOException e) {
            log.error("讀取圖片出錯:{}",e);
            return null;
        }
    }
}

 

參考來源：

https://stackoverflow.com/questions/18522398/fastest-way-to-read-write-images-from-a-file-into-a-bufferedimage