Java上传头像时进行等比缩放
以下为详细代码
import java.awt.Image;import java.awt.image.BufferedImage;import java.io.File;import java.io.FileInputStream;import java.text.DecimalFormat;import java.text.SimpleDateFormat;import java.util.Date;import java.util.Random;import javax.imageio.ImageIO;public class UploadHead {/** * @param file 文件流 * @param path文件存放路径 * @param userId上传用户的Id * @return新文件名 * @throws Exception */public static String uploadHead(File file, String path, int userId) throws Exception {String nowTime = new SimpleDateFormat("yyyyMMddHHmmss").format(new Date());//当前时间Random r = new Random();int x = r.nextInt(999999); //生成一个随机数String newFileName = userId+"-"+x+"-"+nowTime+".jpg";//得到文件的新名字FileInputStream is = new FileInputStream(file); BufferedImage sourceImg = javax.imageio.ImageIO.read(is); int width = sourceImg.getWidth();//原文件宽度 int height = sourceImg.getHeight();//原文件高度 if(width>200||height>200){//等比缩放为200*200的图片，如果宽和高有一个大于200的就进行截取 DecimalFormat df=new DecimalFormat("0.000"); double bili = 0.000;//计算等比 if(width > height){//根据像素大的一方进行等比缩放 bili = Double.parseDouble(df.format(width / 200.0)); }else{ bili = Double.parseDouble(df.format(height / 200.0)); } width = (int) (width / bili); height = (int) (height / bili); } BufferedImage src = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);//根据计算好的宽高新建画布 src.getGraphics().drawImage(sourceImg.getScaledInstance(width, height,Image.SCALE_SMOOTH), 0, 0, null); ImageIO.write(src, "JPEG", new File(path,newFileName));//输出图像is.close();return newFileName ;}}