/*package com.image;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import javax.imageio.ImageIO;
import net.coobird.thumbnailator.Thumbnails;
import net.coobird.thumbnailator.geometry.Positions;
*/
//将图片缩放至m*n尺寸大小(m,n整数型)
Thumbnails.of("C:\rhp.jpg").size(m, n).toFile("D:\rhp.jpg");
//将图片强制缩放至m*n尺寸大小
Thumbnails.of("C:\rhp.jpg").forceSize(m, n).toFile("D:\rhp.jpg");
//将图片强制缩放原图的w倍,其中f是固定参数,w是缩放的参数
Thumbnails.of("C:\rhp.jpg").scale(wf).toFile("D:\rhp.jpg");
//将图片强制缩放指定尺寸,输出格式为“png,jpg...其中我下面写的是bitmap型",使用outputFormat流输出,输出到BufferedImage
BufferedImage im = Thumbnails.of(file).forceSize(160, 160).outputFormat("bmp").asBufferedImage();
可以参照博客https://blog.csdn.net/qiaqia609/article/details/53171149