---
title: Java中处理图片工具类
tags: ['java', 'util']
date: 2018-11-22 16:42:26
---
> 可根据实际情况进行修改
```java
import javax.imageio.IIOImage;
import javax.imageio.ImageIO;
import javax.imageio.ImageWriteParam;
import javax.imageio.ImageWriter;
import javax.imageio.stream.ImageOutputStream;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.*;
import java.util.Iterator;
/**
* 有关图片的工具类
*
* @author johnniang
*/
public class ImageUtils {
private ImageUtils() {
}
/**
* 合并图片，默认从右下角开始堆叠
*
* @param fgImage 前景图片，不能为空
* @param bgImage 背景图片，不能为空
* @param margin 边距，单位：px
* @return 合并后的图片
*/
public static BufferedImage overlay(BufferedImage fgImage, BufferedImage bgImage, int margin) {
Assert.notNull(fgImage, "foreground image must not be null");
Assert.notNull(bgImage, "background image must not be null");
int x = bgImage.getWidth() - fgImage.getWidth() - margin;
int y = bgImage.getHeight() - fgImage.getWidth() - margin;
return overlay(fgImage, bgImage, x, y);
}
/**
* 合并图片，默认从右下角开始堆叠
*
* @param fgImage 前景图片，不能为空
* @param bgImage 背景图片，不能为空
* @return 合并后的图片
*/
public static BufferedImage overlay(BufferedImage fgImage, BufferedImage bgImage) {
return overlay(fgImage, bgImage, 0);
}
/**
* 合并图片
*
* @param fgImage 前景图片，不能为空
* @param bgImage 背景图片，不能为空
* @return 返回合并后的图片
*/
public static BufferedImage overlay(BufferedImage fgImage, BufferedImage bgImage, int x, int y) {
Assert.notNull(fgImage, "foreground image must not be null");
Assert.notNull(bgImage, "background image must not be null");
Assert.isTrue(fgImage.getWidth() < bgImage.getWidth(),
"foreground image's width must less than background image");
Assert.isTrue(fgImage.getHeight() < bgImage.getHeight(),
"forground image's height must less than background image");
Graphics2D g = bgImage.createGraphics();
g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
// draw background image
g.drawImage(bgImage, 0, 0, null);
// draw foreground image
g.drawImage(fgImage, x, y, null);
g.dispose();
return bgImage;
}
/**
* 缩放图片
*
* @param image 原图片，不能为空
* @param zoomLevel 缩放倍数，不能小于0
* @return 返回缩放后的图片
*/
public static BufferedImage zoom(BufferedImage image, float zoomLevel) {
Assert.notNull(image, "image must not be null");
Assert.isTrue(zoomLevel > 0, "zoom level must not be less than 0");
int newImageWidth = (int) (image.getWidth() * zoomLevel);
int newImageHeight = (int) (image.getHeight() * zoomLevel);
BufferedImage newImage = new BufferedImage(newImageWidth, newImageHeight, image.getType());
Graphics2D g = newImage.createGraphics();
g.drawImage(image, 0, 0, newImageWidth, newImageHeight, null);
g.dispose();
return newImage;
}
/**
* 写入图片到指定位置
*
* @param image
* @param filepath
* @param extension
* @throws IOException
*/
public static void writeImage(BufferedImage image, String filepath, String extension) throws IOException {
File file = new File(filepath);
ImageIO.write(image, extension, file);
}
public static void writeImage(BufferedImage image, String formatName, OutputStream output) throws IOException {
ImageIO.write(image, formatName, output);
}
public static BufferedImage readImage(File file) throws IOException {
Assert.notNull(file, "file must not be null");
return ImageIO.read(file);
}
public static BufferedImage readImage(InputStream inputStream) throws IOException {
Assert.notNull(inputStream, "input stream must not be null");
return ImageIO.read(inputStream);
}
public static BufferedImage readImage(byte[] buf) throws IOException {
Assert.notNull(buf, "image byte array must not be null");
return ImageIO.read(new ByteArrayInputStream(buf));
}
/**
* 压缩图片
*
* @param originalImage 原始图片
* @param quantity 压缩质量(0-1)，越小质量越差
* @return 返回新的图片
* @throws IOException 最后写入图片的时候可能出现异常
*/
public static BufferedImage compress(BufferedImage originalImage, float quantity) throws IOException {
Assert.notNull(originalImage, "original image must not be null");
Iterator imageWriterIterator = ImageIO.getImageWritersByFormatName("jpg");
try (ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
ImageOutputStream imageOutputStream = ImageIO.createImageOutputStream(outputStream)) {
// 获取图片写入器
ImageWriter imageWriter = imageWriterIterator.next();
// 设置输出流
imageWriter.setOutput(imageOutputStream);
// 获取图片写入参数
ImageWriteParam param = imageWriter.getDefaultWriteParam();
if (param.canWriteCompressed()) {
// 设置压缩参数
param.setCompressionMode((ImageWriteParam.MODE_EXPLICIT));
param.setCompressionQuality(quantity);
}
// 正式写入压缩内容到输出流
imageWriter.write(null, new IIOImage(originalImage, null, null), param);
// 销毁图片写入器
imageWriter.dispose();
// 读取输出流到图片
return readImage(outputStream.toByteArray());
}
}
}
```
Java中处理图片工具类
