本文实例为大家分享了java项目实现图片等比缩放的具体代码，供大家参考，具体内容如下
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package common; import java.awt.Image;import java.awt.image.BufferedImage;import java.io.FileOutputStream;import java.io.IOException;import java.io.InputStream;import javax.imageio.ImageIO; public class ImageCompressionTask implements Runnable{ private InputStream is; private String fileName; private int width; private int height; /** * 初始化参数 * @param is 图片输入流 * @param file 图片 * @param fileName 图片名称 * @param width 高 * @param height 宽 */ public ImageCompressionTask(InputStream is,String fileName,int width,int height) { this.is=is; this.fileName=fileName; this.width=width; this.height=height; } public void run() { // TODO Auto-generated method stub try{ this.compressPic(); }catch(Exception e){ System.out.println("文件压缩失败"+e); } } private String compressPic() throws Exception{ String path = "E:\\xie\\";//新图片存放路径 String urlPath = path + fileName; BufferedImage buffImage; FileOutputStream output=null; BufferedImage compressPic=null; try { String imagetype = ""; if(fileName.lastIndexOf(".") != -1){ imagetype = fileName.substring(fileName.lastIndexOf(".") + 1).toLowerCase(); } imagetype = imagetype.toLowerCase(); //文件后缀名 output=new FileOutputStream(urlPath); buffImage=ImageIO.read(is); //图片缩放 compressPic=compressPicMin(buffImage,width,height); //输出图片 ImageIO.write(compressPic, imagetype, output); } finally { if(output!=null){ try{ output.close(); }catch(IOException e){ e.getStackTrace(); } } if(is!=null){ is.close(); } } return fileName; } /** * 图片等比缩放 *@param image 图片输入缓存流 *@param outputWidth 图片压缩到的宽 *@param outputHeight 图片压缩到的高 *@return BufferedImage * */ private BufferedImage compressPicMin(BufferedImage image, int outputWidth, int outputHeight) { // TODO Auto-generated method stub if(image==null){ return null; } //如果图片本身的宽和高均小于要压缩到的宽和高，则不压缩直接返回 if(outputWidth>image.getWidth(null)&&outputHeight>image.getHeight(null)){ return image; } int newWidth; int newHeight; //宽和高等比缩放的率 double rate1=(double)image.getWidth(null)/(double)outputWidth; double rate2=(double)image.getHeight(null)/(double)outputHeight; //控制缩放大小 double rate=rate1<rate2 ? rate1:rate2; newWidth=(int) (image.getWidth(null)/rate); newHeight=(int) (image.getHeight(null)/rate); BufferedImage newImage=new BufferedImage(newWidth, newHeight,BufferedImage.TYPE_INT_RGB); newImage.createGraphics().drawImage(image.getScaledInstance(newWidth, outputHeight, Image.SCALE_SMOOTH), 0, 0, null); return newImage; } public int getWidth() { return width; } public void setWidth(int width) { this.width = width; } public int getHeight() { return height; } public void setHeight(int height) { this.height = height; } } |
创建ImageTest写一个main（）
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package test1; import java.io.File;import java.io.FileInputStream;import java.io.InputStream;import java.util.concurrent.ArrayBlockingQueue;import java.util.concurrent.ExecutorService;import java.util.concurrent.Executors;import java.util.concurrent.LinkedBlockingQueue;import java.util.concurrent.SynchronousQueue;import java.util.concurrent.ThreadPoolExecutor;import java.util.concurrent.TimeUnit; import common.ImageCompressionTask; public class ImageTest { public static void main(String[] args){ String imgName = System.currentTimeMillis() + "_" + ((int) (Math.random() * 900) + 100) + "." + "jpg"; File f=new File("E:\\xie\\xxx.jpg"); try { InputStream input = new FileInputStream(f); ImageCompressionTask r=new ImageCompressionTask(input, imgName, 520, 320); /* * 方法一： * Thread thread1 = new Thread(r); thread1.start(); // 启动线程 */ /* * 方法二：使用ThreadPoolExecutor创建线程池，并不提倡我们直接使用ThreadPoolExecutor * */ /* ThreadPoolExecutor executor = new ThreadPoolExecutor( 5, //核心池的大小（即线程池中的线程数目大于这个参数时，提交的任务会被放进任务缓存队列） 10, //线程池最大能容忍的线程数 200, //线程存活时间 TimeUnit.MILLISECONDS, //参数keepAliveTime的时间单位 new ArrayBlockingQueue<Runnable>(5) //任务缓存队列，用来存放等待执行的任务 ); executor.execute(r);*/ /* * 方法三：并不提倡我们直接使用ThreadPoolExecutor，而是使用Executors类中提供的几个静态方法来创建线程池 * 以下是三个静态方法 * Executors.newCachedThreadPool(); //创建一个缓冲池，缓冲池容量大小为Integer.MAX_VALUE * Executors.newSingleThreadExecutor(); //创建容量为1的缓冲池 * Executors.newFixedThreadPool(int); //创建固定容量大小的缓冲池 */ newCachedThreadPool().execute(r); //newSingleThreadExecutor().execute(r); //newFixedThreadPool(10).execute(r); System.out.println("图片上传成功"); } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } } /*静态方法的具体实现 * Executors.newCachedThreadPool() * 创建一个缓冲池，缓冲池容量大小为Integer.MAX_VALUE */ public static ExecutorService newCachedThreadPool() { return new ThreadPoolExecutor(0, Integer.MAX_VALUE, 60L, TimeUnit.SECONDS, new SynchronousQueue<Runnable>()); } /*静态方法的具体实现 * Executors.newSingleThreadExecutor() * 创建容量为1的缓冲池 */ public static ExecutorService newSingleThreadExecutor() { return new ThreadPoolExecutor(1, 1, 0L, TimeUnit.MILLISECONDS, new LinkedBlockingQueue<Runnable>()); } /*静态方法的具体实现 * Executors.newFixedThreadPool(int) * 创建固定容量大小的缓冲池 */ public static ExecutorService newFixedThreadPool(int nThreads) { return new ThreadPoolExecutor(nThreads, nThreads, 0L, TimeUnit.MILLISECONDS, new LinkedBlockingQueue<Runnable>()); }} |
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持服务器之家。
原文链接：https://blog.csdn.net/xiegongmiao/article/details/78624317
