java 读取 tiff文件dpi

以下是Java读取TIFF文件DPI的示例代码：

import javax.imageio.ImageIO;
import javax.imageio.metadata.IIOMetadata;
import javax.imageio.plugins.tiff.TIFFImageReadParam;
import javax.imageio.stream.ImageInputStream;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;

public class ReadTiffDpi {
    public static void main(String[] args) throws IOException {
        File file = new File("input.tiff");
        ImageInputStream iis = ImageIO.createImageInputStream(file);
        TIFFImageReadParam param = new TIFFImageReadParam();
        param.setDecodeTiled(false);
        ImageIO.setUseCache(false);
        BufferedImage image = ImageIO.read(iis);
        IIOMetadata metadata = ImageIO.getImageReadersByFormatName("TIFF").next().getImageMetadata(0);
        String[] names = metadata.getMetadataFormatNames();
        for (String name : names) {
            System.out.println("Format name: " + name);            displayMetadata(metadata.getAsTree(name));
        }
    }

    private static void displayMetadata(Node root) {
        displayMetadata(root, 0);
    }

    private static void indent(int level) {
        for (int i = 0; i < level; i++)
            System.out.print("    ");
    }

    private static void displayMetadata(Node node, int level) {
        // Print node name and attribute values
        indent(level);
        System.out.print("<" + node.getNodeName());
        NamedNodeMap map = node.getAttributes();
        if (map != null) {
            for (int i = 0; i < map.getLength(); i++) {
                Node attr = map.item(i);
                System.out.print(" " + attr.getNodeName() +
                        "=\"" + attr.getNodeValue() + "\"");
            }
        }

        // Print children recursively
        Node child = node.getFirstChild();
        if (child == null) {
            // No children, so close element and return
            System.out.println("/>");
            return;
        }

        // Children, so close current tag
        System.out.println(">");
        while (child != null) {
            // Print child recursively
            displayMetadata(child, level + 1);
            child = child.getNextSibling();
        }

        // Print closing tag
        indent(level);
        System.out.println("</" + node.getNodeName() + ">");
    }
}

该代码使用Java的ImageIO库读取TIFF文件，并使用TIFFImageReadParam类设置解码参数。然后，它使用ImageIO.getImageReadersByFormatName("TIFF").next().getImageMetadata(0)方法获取元数据，并使用displayMetadata()方法显示元数据。其中，DPI信息可以在元数据中找到。