加哥最近在写代码过程中需要将上传的图片进行自动压缩，但是又不能借助插件，下来就把代码分享给志同道合的小伙伴吧，在运行过程中一定需要注意图片路径输入正确。
1.java借助awt实现图片的压缩的方式一
public static void main(String[] args) { try { String inputImagePath = "D:\\500540b041a30ad044b5a19344f1b24f.png"; // 输入图片路径 String outputImagePath = "D:\\500540b041a30ad044b5a19344f1b24f.png"; // 输出图片路径 int targetSizeKB = 8; // 目标压缩大小（KB） BufferedImage image = ImageIO.read(new File(inputImagePath)); Image compressedImage = compressImage(image, targetSizeKB); ImageIO.write((BufferedImage) compressedImage, "jpg", new File(outputImagePath)); } catch (IOException ex) { ex.printStackTrace(); } } public static Image compressImage(BufferedImage image, int targetSizeKB) { // 计算目标图片的尺寸 long targetSizeBytes = targetSizeKB * 1024; long originalSizeBytes = getImageSize(image); double compressionRatio = (double) targetSizeBytes / originalSizeBytes; int targetWidth = (int) (image.getWidth() * Math.sqrt(compressionRatio)); int targetHeight = (int) (image.getHeight() * Math.sqrt(compressionRatio)); // 使用ImageIO进行压缩 BufferedImage compressedImage = new BufferedImage(targetWidth, targetHeight, BufferedImage.TYPE_INT_RGB); compressedImage.getGraphics().drawImage(image.getScaledInstance(targetWidth, targetHeight, Image.SCALE_SMOOTH), 0, 0, null); return compressedImage; } public static long getImageSize(BufferedImage image) { File tempFile; try { tempFile = File.createTempFile("temp", ".tmp"); ImageIO.write(image, "jpg", tempFile); long size = tempFile.length(); tempFile.delete(); return size; } catch (IOException ex) { ex.printStackTrace(); return 0; } }
2.java借助awt实现图片的压缩的方式二
public static void main(String[] args) throws IOException {
// 读取图片文件
/**File input = new File("D:\\1691455935941.jpg");
BufferedImage image = ImageIO.read(input);
// 压缩图片
BufferedImage compressedImage = compress(image, 0.5f);
// 保存压缩后的图片
File output = new File("D:\\");
ImageIO.write(compressedImage, "jpg", output);**/
File img = new File("D:\\500540b041a30ad044b5a19344f1b24f.jpg");
System.out.println("输入的图片大小：" + img.length()/1024 + "KB");
String outputDir = "D:\\";
PicUtils.thumbnail_w_h(img, 0,0, outputDir);
}
public static BufferedImage compress(BufferedImage image, float quality) throws IOException {
// 创建新的图片对象
BufferedImage compressedImage = new BufferedImage(image.getWidth(), image.getHeight(), BufferedImage.TYPE_INT_RGB);
// 设置压缩质量
java.util.Iterator<ImageWriter> iterator = ImageIO.getImageWritersByFormatName("jpg");
ImageWriter writer = iterator.next();
ImageWriteParam param = writer.getDefaultWriteParam();
param.setCompressionMode(ImageWriteParam.MODE_EXPLICIT);
param.setCompressionQuality(quality);
// 压缩图片
writer.setOutput(ImageIO.createImageOutputStream(compressedImage));
writer.write(null, new IIOImage(image, null, null), param);
return compressedImage;
}
/**
* 按照指定的宽高压缩原图
* @param img
* @param outputDir
*/
public static void thumbnail(File img, int destWidth, int destHeight,String outputDir){
System.out.println("图片压缩开始");
long startTime = System.currentTimeMillis();
try {
//读取源图
BufferedImage BI = ImageIO.read(img);
double srcWidth = BI.getWidth(); // 源图宽度
double srcHeight = BI.getHeight(); // 源图高度
if ((int)srcWidth >= destWidth && (int)srcHeight >= destHeight) {
String imageFullName = img.getName();
String prefix = imageFullName.substring(0,imageFullName.lastIndexOf("."));
String suffix = imageFullName.substring(imageFullName.lastIndexOf("."));
String newName = prefix+suffix ;
OutputStream fos =new FileOutputStream(outputDir+File.separatorChar+newName);
Image image = BI.getScaledInstance(destWidth, destHeight, Image.SCALE_SMOOTH);
BufferedImage tag = new BufferedImage(destWidth, destHeight,BufferedImage.TYPE_INT_RGB);
Graphics g = tag.getGraphics();
g.setColor(Color.RED);
g.drawImage(image, 0, 0, null); //绘制处理后的图
g.dispose();
ImageIO.write(tag, "JPEG", fos);
System.out.println("图片压缩结束");
long endTime = System.currentTimeMillis();
System.out.println("图片压缩共计耗时：" +(endTime-startTime)+"毫秒" );
}
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
/**
* 按照宽高等比例缩放(缩小或放大)
* @param img
* @param width
* @param height
* @param outputDir
*/
public static void thumbnail_w_h(File img,int destWidth,int destHeight,String outputDir){
try {
BufferedImage bi = ImageIO.read(img);
double srcWidth = bi.getWidth(); // 源图宽度
double srcHeight = bi.getHeight(); // 源图高度
double scale = 1;//缩放比例因子，大于1表示放大，小于1表示缩小
if (destWidth > 0 && destHeight > 0) {
//下面这个缩放比例因子取值很好理解，目标尺寸和原图尺寸的比值越大，
//表示缩放的比率越小，也就代表图片变形的越小，就取影响图片变形小的比例因子
scale = destHeight/srcHeight < destWidth/srcWidth ? destHeight/srcHeight : destWidth/srcWidth;
}
thumbnail(img, (int)(srcWidth * scale),(int)(srcHeight * scale),outputDir);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
