我看了网上大多数对图片的压缩都是基于对图片width和hight进行裁剪来降低图片实际大小,但这种方式容易导致图片内容的丢失,所以推荐大家采用以下这种方式
import java.awt.image.BufferedImage;
import java.awt.image.ColorModel;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import javax.imageio.IIOImage;
import javax.imageio.ImageIO;
import javax.imageio.ImageWriteParam;
import javax.imageio.ImageWriter;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
public class Picdownload {
private final static Logger logger = LoggerFactory.getLogger(Picdownload.class);
/**
* 压缩图片
* @param file
* @param qality 参数qality是取值0~1范围内 代表压缩的程度
* @return
* @throws IOException
*/
public static File compressPictureByQality(File file,float qality) throws IOException {
BufferedImage src = null;
FileOutputStream out = null;
ImageWriter imgWrier;
ImageWriteParam imgWriteParams;
logger.info("开始设定压缩图片参数");
// 指定写图片的方式为 jpg
imgWrier = ImageIO.getImageWritersByFormatName("jpg").next();
imgWriteParams = new javax.imageio.plugins.jpeg.JPEGImageWriteParam(
null);
// 要使用压缩,必须指定压缩方式为MODE_EXPLICIT
imgWriteParams.setCompressionMode(imgWriteParams.MODE_EXPLICIT);
// 这里指定压缩的程度,参数qality是取值0~1范围内,
imgWriteParams.setCompressionQuality(qality);
imgWriteParams.setProgressiveMode(imgWriteParams.MODE_DISABLED);
ColorModel colorModel =ImageIO.read(file).getColorModel();// ColorModel.getRGBdefault();
imgWriteParams.setDestinationType(new javax.imageio.ImageTypeSpecifier(
colorModel, colorModel.createCompatibleSampleModel(32, 32)));
logger.info("结束设定压缩图片参数");
if (!file.exists()) {
logger.info("Not Found Img File,文件不存在");
throw new FileNotFoundException("Not Found Img File,文件不存在");
} else {
logger.info("图片转换前大小"+file.length()+"字节");
src = ImageIO.read(file);
out = new FileOutputStream(file);
imgWrier.reset();
// 必须先指定 out值,才能调用write方法, ImageOutputStream可以通过任何
// OutputStream构造
imgWrier.setOutput(ImageIO.createImageOutputStream(out));
// 调用write方法,就可以向输入流写图片
imgWrier.write(null, new IIOImage(src, null, null),
imgWriteParams);
out.flush();
out.close();
logger.info("图片转换后大小"+file.length()+"字节");
return file;
}
}
}