java MultipartFile JPG图片 压缩大小到小于2mb 再转回MultipartFile
时间: 2024-04-02 08:30:24 浏览: 87
在Java中,可以使用MultipartFile类来处理上传的文件。要将JPG图片压缩到小于2MB并转回MultipartFile对象,可以按照以下步骤进行操作:
1. 将MultipartFile对象转换为BufferedImage对象:
```java
BufferedImage image = ImageIO.read(multipartFile.getInputStream());
```
2. 压缩图片大小:
```java
double scaleFactor = Math.sqrt((double) (2 * 1024 * 1024) / (double) multipartFile.getSize());
int targetWidth = (int) (image.getWidth() * scaleFactor);
int targetHeight = (int) (image.getHeight() * scaleFactor);
BufferedImage resizedImage = new BufferedImage(targetWidth, targetHeight, BufferedImage.TYPE_INT_RGB);
Graphics2D graphics = resizedImage.createGraphics();
graphics.drawImage(image, 0, 0, targetWidth, targetHeight, null);
graphics.dispose();
```
3. 将压缩后的BufferedImage对象转换回MultipartFile对象:
```java
ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
ImageIO.write(resizedImage, "jpg", outputStream);
MultipartFile compressedFile = new MockMultipartFile("file.jpg", "file.jpg", "image/jpeg", outputStream.toByteArray());
```
这样,你就可以得到一个大小小于2MB的压缩后的MultipartFile对象。
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