简介

我们在项目中经常会遇到图片上传的需求，如商品图片，但图片太大的话，在客户端加载太慢影响用户体验，所有一般会将图片进行压缩。

实现

原图

添加依赖

net.coobird

thumbnailator

0.4.8

按质量压缩

import java.io.File;

import java.io.FileOutputStream;

import net.coobird.thumbnailator.Thumbnails;

public class Client {

public static void main(String[] args) throws Exception {

Thumbnails.of(new File("D:/showqrcode.jpg"))

.scale(1f) //图片大小(长宽)压缩比例 从0-1，1表示原图

.outputQuality(0.5f) //图片质量压缩比例 从0-1，越接近1质量越好

.toOutputStream(new FileOutputStream("D:/showqrcode_50.jpg"));

}

}

压缩后图片

图片大小从665KB压缩到了77KB。

按比例缩放

import java.io.File;

import java.io.FileOutputStream;

import net.coobird.thumbnailator.Thumbnails;

public class Client2 {

public static void main(String[] args) throws Exception {

Thumbnails.of(new File("D:/showqrcode.jpg"))

.scale(0.5f) //图片大小(长宽)压缩 从0按照

.outputQuality(0.5f) //图片质量压缩比例 从0-1，越接近1质量越好

.toOutputStream(new FileOutputStream("D:/showqrcode_50%.jpg"));

}

}

按大小和比例缩放

import java.io.File;

import java.io.FileOutputStream;

import net.coobird.thumbnailator.Thumbnails;

public class Client21 {

public static void main(String[] args) throws Exception {

Thumbnails.of(new File("D:/showqrcode.jpg"))

.size(500, 300) // 图片比例不变

.toOutputStream(new FileOutputStream("D:/showqrcode_500_300.jpg"));

}

}

按大小缩放

import java.io.File;

import java.io.FileOutputStream;

import net.coobird.thumbnailator.Thumbnails;

public class Client22 {

public static void main(String[] args) throws Exception {

Thumbnails.of(new File("D:/showqrcode.jpg"))

.forceSize(500, 300) //不保持图片比例

.toOutputStream(new FileOutputStream("D:/showqrcode_500_300.jpg"));

}

}

旋转

import java.io.File;

import java.io.FileOutputStream;

import net.coobird.thumbnailator.Thumbnails;

public class Client3 {

public static void main(String[] args) throws Exception {

Thumbnails.of(new File("D:/showqrcode.jpg"))

.forceSize(500, 300)

.rotate(90f) //向右旋转

.toOutputStream(new FileOutputStream("D:/showqrcode+90.jpg"));

}

}

加水印

水印图片

import java.io.File;

import java.io.IOException;

import javax.imageio.ImageIO;

import net.coobird.thumbnailator.Thumbnails;

import net.coobird.thumbnailator.geometry.Positions;

public class Client4 {

public static void main(String[] args) throws IOException {

Thumbnails.of("D:/showqrcode.jpg")

.size(1280, 1024)

.watermark(Positions.BOTTOM_RIGHT, ImageIO.read(new File("D:/watermark.jpg")),

0.5f) //位置，水印来源，透明度

.outputQuality(0.8f)

.toFile("D:/showqrcode_watermark_bottom_right.jpg");

}

}

裁剪

import java.io.IOException;

import net.coobird.thumbnailator.Thumbnails;

import net.coobird.thumbnailator.geometry.Positions;

public class Client5 {

public static void main(String[] args) throws IOException {

Thumbnails.of("D:/showqrcode.jpg")

.sourceRegion(Positions.CENTER, 800, 600) //位置，宽，高

.size(800, 600)

.keepAspectRatio(false)

.toFile("D:/showqrcode_region_center.jpg");

}

}

拼接

import java.awt.Graphics;

import java.awt.image.BufferedImage;

import java.io.ByteArrayInputStream;

import java.io.ByteArrayOutputStream;

import java.io.File;

import java.io.FileOutputStream;

import java.io.IOException;

import java.util.ArrayList;

import java.util.List;

import java.util.Objects;

import javax.imageio.ImageIO;

public class Client6 {

public static void main(String[] args) throws Exception {

byte[] bytes = joinImages(false, new File("D:/showqrcode.jpg"), new File("D:/showqrcode.jpg"));

if (Objects.nonNull(bytes)) {

new ByteArrayInputStream(bytes).transferTo(new FileOutputStream("D:/showqrcode_join.jpg"));

}

}

/**

* 将多张图片拼接成一张

*

* @param horizontal 是否为水平拼接

* @param files 文件列表

* @return 拼接后的文件字节数组

*/

private static byte[] joinImages(boolean horizontal, File... files) throws IOException {

if (Objects.isNull(files) || files.length == 0) {

return null;

}

List imageList = new ArrayList<>();

for (File file : files) {

BufferedImage image = ImageIO.read(file);

imageList.add(image);

}

int height = imageList.get(0).getHeight();

int width = imageList.get(0).getWidth();

if (horizontal) {

width = imageList.stream().mapToInt(BufferedImage::getWidth).sum();

} else {

height = imageList.stream().mapToInt(BufferedImage::getHeight).sum();

}

//创建拼接后的图片画布，参数分别为宽，高，类型，这里我们使用RGB3元色类型

BufferedImage resultImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);

Graphics graphics = resultImage.getGraphics();

int previousWidth = 0;

int previousHeight = 0;

for (BufferedImage image : imageList) {

//向画布上画图片

graphics.drawImage(image, previousWidth, previousHeight, null);

if (horizontal) {

previousWidth += image.getWidth();

} else {

previousHeight += image.getHeight();

}

}

ByteArrayOutputStream output = new ByteArrayOutputStream();

ImageIO.write(resultImage, "jpg", output);

return output.toByteArray();

}

}

更多用法请参考官方文档

总结

图片经过以上处理之后都会去除EXIF信息，关于EXIF详情，请查看java获取图片的GPS信息

参考