JAVA－使用Thumbnails压缩图片

使用Thumbnails压缩图片

<!-- https://mvnrepository.com/artifact/net.coobird/thumbnailator 压缩图片插件-->
<dependency>
<groupId>net.coobird</groupId>
<artifactId>thumbnailator</artifactId>
<version>0.4.8</version>
</dependency>




package jjgis.springboot.com.rqswapp.webservice;
import net.coobird.thumbnailator.Thumbnails;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
public class PicUtils {
private static Logger logger = LoggerFactory.getLogger(PicUtils.class);

// public static void main(String[] args) throws IOException {
// byte[] bytes = FileUtils.readFileToByteArray(new File("D:\\1.jpg"));
// long l = System.currentTimeMillis();
// bytes = PicUtils.compressPicForScale(bytes, 300, "x");// 图片小于300kb
// System.out.println(System.currentTimeMillis() - l);
// FileUtils.writeByteArrayToFile(new File("D:\\dd1.jpg"), bytes);
// }

/**
* 根据指定大小压缩图片
*
* @param imageBytes 源图片字节数组
* @param desFileSize 指定图片大小，单位kb
* @param imageId 影像编号
* @return 压缩质量后的图片字节数组
*/
public static byte[] compressPicForScale(byte[] imageBytes, long desFileSize, String imageId) {
if (imageBytes == null || imageBytes.length <= 0 || imageBytes.length < desFileSize * 1024) {
return imageBytes;
}
long srcSize = imageBytes.length;
double accuracy = getAccuracy(srcSize / 1024);
try {
while (imageBytes.length > desFileSize * 1024) {
ByteArrayInputStream inputStream = new ByteArrayInputStream(imageBytes);
ByteArrayOutputStream outputStream = new ByteArrayOutputStream(imageBytes.length);
Thumbnails.of(inputStream)
.scale(accuracy)
.outputQuality(accuracy)
.toOutputStream(outputStream);
imageBytes = outputStream.toByteArray();
}
logger.info("【图片压缩】imageId={} | 图片原大小={}kb | 压缩后大小={}kb",
imageId, srcSize / 1024, imageBytes.length / 1024);
} catch (Exception e) {
logger.error("【图片压缩】msg=图片压缩失败!", e);
}
return imageBytes;
}

/**
* 自动调节精度(经验数值)
*
* @param size 源图片大小
* @return 图片压缩质量比
*/
private static double getAccuracy(long size) {
double accuracy;
if (size < 900) {
accuracy = 0.85;
} else if (size < 2047) {
accuracy = 0.6;
} else if (size < 3275) {
accuracy = 0.44;
} else {
accuracy = 0.4;
}
return accuracy;
}

}