POM文件添加Maven依赖
java
<dependency>
<groupId>gui.ava</groupId>
<artifactId>html2image</artifactId>
<version>0.9</version>
</dependency>主要代码：
java
String coverPath = null;
try {
HtmlImageGenerator imageGenerator = new HtmlImageGenerator();
imageGenerator.loadHtml(lzDocs.getContent());//也可以根据html url引用 loadUrl的方式加载
Thread.sleep(1000); //有时会有加载图片延迟，因此这里设置下延时
BufferedImage cover = imageGenerator.getBufferedImage();//获取图片
cover = ImageUtils.getCoverImage(cover);//将图片转成综略图
String coverName = UUIDGenerator.generate().toString() + ".png";
MultipartFile mpFile = FileUtils.imageToMpFile(cover, coverName);
coverPath = sysBaseAPI.upload(mpFile,"cover", uploadType);//上传文件到服务器
} catch (Exception e) {
e.printStackTrace();
}图片工具类，供主要代码调用
java
public class ImageUtils {
/**
* bufferedImage转InputStream
*/
public static InputStream bufferedImageToInputStream(BufferedImage image) {
ByteArrayOutputStream os = new ByteArrayOutputStream();
try {
ImageIO.write(image, "png", os);
InputStream input = new ByteArrayInputStream(os.toByteArray());
return input;
} catch (IOException e) {
}
return null;
}
/**
* 获取图片大小信息
*/
public static Rectangle getImgRect(BufferedImage image) throws IOException {
Iterator readers = ImageIO.getImageReadersByFormatName("png");
ImageReader reader = (ImageReader) readers.next();
InputStream source = bufferedImageToInputStream(image);
ImageInputStream iis = ImageIO.createImageInputStream(source);
reader.setInput(iis, true);
int imageIndex = 0;
return new Rectangle(0, 0, reader.getWidth(imageIndex), reader.getHeight(imageIndex));
}
/**
* 图片裁剪，按指定大小裁剪
*/
public static BufferedImage imageCut(BufferedImage image, Rectangle rect) throws IOException {
// 取得图片读入器
Iterator readers = ImageIO.getImageReadersByFormatName("png");
System.out.println(readers);
ImageReader reader = (ImageReader) readers.next();
System.out.println(reader);
// 取得图片读入流
InputStream source = bufferedImageToInputStream(image);
ImageInputStream iis = ImageIO.createImageInputStream(source);
reader.setInput(iis, true);
// 图片参数
ImageReadParam param = reader.getDefaultReadParam();
int imageIndex = 0;
//Rectangle rect = new Rectangle(0, 0, reader.getWidth(imageIndex), 100);
param.setSourceRegion(rect);
BufferedImage bi = reader.read(0, param);
iis.close();
source.close();
return bi;
}
/**
* 压缩图片，用于高质量图片质量降低，改变图片大小
*/
public static BufferedImage compressImage(BufferedImage imageByte, int ppi) {
BufferedImage smallImage = null;
int width = 0, height = 0;
if (imageByte == null)
return null;
InputStream byteInput = bufferedImageToInputStream(imageByte);
try {
Image image = ImageIO.read(byteInput);
int w = image.getWidth(null);
int h = image.getHeight(null);
// adjust weight and height to avoid image distortion
double scale = 0;
scale = Math.min((float) ppi / w, (float) ppi / h);
width = (int) (w * scale);
width -= width % 4;
height = (int) (h * scale);
if (scale >= (double) 1)
return imageByte;
BufferedImage buffImg = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
buffImg.getGraphics().drawImage(image.getScaledInstance(width, height, Image.SCALE_SMOOTH), 0, 0, null);
//ByteArrayOutputStream out = new ByteArrayOutputStream();
//ImageIO.write(buffImg, "png", out);
smallImage = buffImg;
} catch (IOException e) {
e.printStackTrace();
}
return smallImage;
}
/**
* 将BufferedImage转换为byte[]
* @param image
* @return
*/
public static byte[] bufferedImageToByteArray(BufferedImage image) throws IOException{
ByteArrayOutputStream os = new ByteArrayOutputStream();
ImageIO.write(image, "png", os);
return os.toByteArray();
}
/**
* 将BufferedImage转换pdf
*/
public static String imageToPdf(List<BufferedImage> images) throws IOException {
log.info("图片转pdf开始===============");
String newFile = StrUtil.uuid().replace("-", "") + ".pdf";
PdfWriter pdfWriter = new PdfWriter( newFile);
PdfDocument pdfDocument = new PdfDocument(pdfWriter);
Document document = new Document(pdfDocument);
for (BufferedImage image : images) {
byte[] data = bufferedImageToByteArray(image);
com.itextpdf.layout.element.Image img = new com.itextpdf.layout.element.Image(ImageDataFactory.createPng(data));
document.add(img);
}
document.close();
log.info("图片转pdf结束===============");
return newFile;
}
/**
* 获取缩略图图片，用作封面，按长宽比例设备，高度太高裁掉，高度太低补余白
*/
public static BufferedImage getCoverImage (BufferedImage originalImage) throws IOException {
BufferedImage result = null;
// 获取图片的长宽
int originalWidth = originalImage.getWidth();
int originalHeight = originalImage.getHeight();
Rectangle rect = ImageUtils.getImgRect(originalImage);
if (rect.getHeight() > rect.getWidth()) {
rect.setRect(0,0, rect.getWidth(), rect.getWidth() / 1.3);
result = ImageUtils.imageCut(originalImage, rect);
} else {
int newWidth = 800;
int newHeight = 600;
// 计算缩放比例
double scale = Math.min((double) newWidth / originalWidth, (double) newHeight / originalHeight);
// 计算调整后的长宽
int scaledWidth = (int) (originalWidth * scale);
int scaledHeight = (int) (originalHeight * scale);
// 创建新的BufferedImage对象，添加余白
BufferedImage resizedImage = new BufferedImage(newWidth, newHeight, BufferedImage.TYPE_INT_RGB);
Graphics2D g = resizedImage.createGraphics();
Color fillColor = new Color(255, 255, 255); // 白颜色
g.setColor(fillColor);
g.fillRect(0, 0, newWidth, newHeight);
g.drawImage(originalImage, 0, 0, scaledWidth, scaledHeight, null);
g.dispose();
result = resizedImage;
}
return result;
}
}