Java實現(xiàn)根據(jù)圖片url下載圖片并動態(tài)添加水印

更新時間：2026年01月08日 08:42:59 作者：專注寫bug

這篇文章主要為大家詳細介紹了如何使用Java實現(xiàn)根據(jù)圖片url下載圖片并動態(tài)添加水印,文中的示例代碼講解詳細,感興趣的小伙伴可以了解下

前言

為了一些數(shù)據(jù)安全性，需要將圖片打上自定義的水印。水印需要滿足下列設置。

支持橫向或縱向。
支持單挑或多條水印。
支持自定義顏色配置。
支持水印字體大小配置與透明度配置。

完整代碼

package img;

import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.Response;

import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.StandardOpenOption;
import java.util.Objects;
import java.util.UUID;

/**
 * 變量控制水印
 */
public class WaterMarkExample {

    private static BufferedImage getBufferedImageByUrl(String imageUrl) throws IOException {
        // 從URL獲取圖片
        byte[] imageBytes = getImageBytesFromUrl(imageUrl);
        BufferedImage image = ImageIO.read(new java.io.ByteArrayInputStream(imageBytes));
        return image;
    }

    private static byte[] getImageBytesFromUrl(String imageUrl) throws IOException {
        OkHttpClient client = UnsafeOkHttpClient.getUnsafeClient();
        Request request = new Request.Builder()
                .url(imageUrl)
                .build();
        try (Response response = client.newCall(request).execute()) {
            return response.body().bytes();
        }
    }

    private static byte[] convertImageToBytes(BufferedImage image) throws IOException {
        ByteArrayOutputStream bos = new ByteArrayOutputStream();
        ImageIO.write(image, "png", bos);
        return bos.toByteArray();
    }

    /**
     * 圖片追加水印
     * @param image 原始圖片信息
     * @param watermarkText 水印文字
     * @param fontFilePath 字體文件
     * @param isItalic 是否字體為斜體
     * @param isSkew 水印是否傾斜
     * @param isMultiLine 水印行數(shù)是否為多行
     * @param waterMarkLineSize 水印行數(shù)
     * @param waterMarkFontSize 水印字體大小
     * @param alpha 透明度 [0,1]
     * @param waterMarkColor 水印顏色 取值來源 java.awt.Color
     * @return
     */
    private static BufferedImage addWatermark(BufferedImage image, String watermarkText, String fontFilePath,
                                              boolean isItalic, boolean isSkew, boolean isMultiLine,int waterMarkLineSize,float waterMarkFontSize,float alpha,Color waterMarkColor) {
        BufferedImage watermarkedImage = new BufferedImage(image.getWidth(), image.getHeight(), BufferedImage.TYPE_INT_RGB);
        Graphics2D g2d = watermarkedImage.createGraphics();
        g2d.drawImage(image, 0, 0, null);

        try {
            // 指定字體文件
            Font customFont = Font.createFont(Font.TRUETYPE_FONT, new File(fontFilePath));
            int fontStyle = isItalic? Font.ITALIC : Font.PLAIN;
            Font derivedFont = customFont.deriveFont(fontStyle, waterMarkFontSize);

            // 默認演示使用，linux使用下面的代碼會加載失敗字體
            //g2d.setFont(new Font("微軟雅黑", isItalic? Font.ITALIC : Font.PLAIN, 30));

            g2d.setFont(derivedFont);
        } catch (FontFormatException | IOException e) {
            e.printStackTrace();
            g2d.setFont(new Font("Arial", isItalic? Font.ITALIC : Font.PLAIN, 30));
        }

        // 水印的顏色
        g2d.setColor(waterMarkColor);
        AlphaComposite alphaComposite = AlphaComposite.getInstance(AlphaComposite.SRC_OVER, alpha);
        g2d.setComposite(alphaComposite);

        // 圖片的尺寸
        int stringWidth = g2d.getFontMetrics().stringWidth(watermarkText);
        int stringHeight = g2d.getFontMetrics().getHeight();

        if (isMultiLine) {
            // 多行
            if (isSkew) {
                // 旋轉(zhuǎn)角度
                double rotationAngle = Math.toRadians(-45);
                int xStep = stringWidth + 50;
                int yStep = stringHeight + 50;
                for (int y = 0; y < image.getHeight(); y += yStep) {
                    for (int x = 0; x < image.getWidth(); x += xStep) {
                        AffineTransform oldTransform = g2d.getTransform();
                        g2d.rotate(rotationAngle, x + stringWidth / 2, y + stringHeight / 2);
                        g2d.drawString(watermarkText, x, y);
                        g2d.setTransform(oldTransform);
                    }
                }
            } else {
                waterMarkLineSize = Objects.isNull(waterMarkLineSize) ? 1:waterMarkLineSize;
                int x = (image.getWidth() - stringWidth) / 2;
                int y = (image.getHeight() - stringHeight) / 2;
                for (int i = 0; i < waterMarkLineSize; i++) {
                    g2d.drawString(watermarkText, x, y + i * (stringHeight + 20));
                }
            }
        } else {
            // 單行
            if (isSkew) {
                double rotationAngle = Math.toRadians(-45);
                int x = (image.getWidth() - stringWidth) / 2;
                int y = (image.getHeight() - stringHeight) / 2;
                AffineTransform oldTransform = g2d.getTransform();
                g2d.rotate(rotationAngle, x + stringWidth / 2, y + stringHeight / 2);
                g2d.drawString(watermarkText, x, y);
                g2d.setTransform(oldTransform);
            } else {
                int x = (image.getWidth() - stringWidth) / 2;
                int y = (image.getHeight() - stringHeight) / 2;
                g2d.drawString(watermarkText, x, y);
            }
        }

        g2d.dispose();
        return watermarkedImage;
    }

    public static void saveImage(byte[] imageBytes, String filePath) throws IOException {
        Path path = Path.of(filePath);
        Files.write(path, imageBytes, StandardOpenOption.CREATE, StandardOpenOption.TRUNCATE_EXISTING);
    }
    public static void main(String[] args) throws IOException {
        String imageUrl = "https://i-blog.csdnimg.cn/direct/d102cabed76c4cd9b74b9469f42a4353.png";
        BufferedImage bufferedImageByUrl = getBufferedImageByUrl(imageUrl);

        String fontFilePath = System.getProperty("user.dir")+"/fill2word"+"/font/simfang.ttf";
        BufferedImage bufferedImage = addWatermark(bufferedImageByUrl,"香蕉集團的香蕉不拿拿愛吃香蕉香蕉集團的香蕉不拿拿愛吃香蕉香蕉集團的香蕉不拿拿愛吃香蕉",fontFilePath,
                false,false,true,3,50,0.3f,Color.blue);
        byte[] watermarkedImageBytes = convertImageToBytes(bufferedImage);

        String out_file_base_path = "doc/"+ UUID.randomUUID();
        System.out.println(out_file_base_path);
        saveImage(watermarkedImageBytes,out_file_base_path+".png");
    }
}

一些補充

1、使用okhttp下載時提示ssl證書校驗失敗

通常證書合法，直接使用下列代碼即可進行http請求和下載。

OkHttpClient client = new OkHttpClient();

如果需要忽略ssl校驗，可以自定義OkHttpClient，如下所示：

import okhttp3.OkHttpClient;
import javax.net.ssl.*;
import java.security.cert.CertificateException;
import java.security.cert.X509Certificate;

public class UnsafeOkHttpClient {
    public static OkHttpClient getUnsafeClient() {
        try {
            // 創(chuàng)建一個信任所有證書的 TrustManager
            final X509TrustManager trustManager = new X509TrustManager() {
                @Override
                public void checkClientTrusted(X509Certificate[] chain, String authType) throws CertificateException {}
                @Override
                public void checkServerTrusted(X509Certificate[] chain, String authType) throws CertificateException {}
                @Override
                public X509Certificate[] getAcceptedIssuers() {
                    return new X509Certificate[0];
                }
            };

            // 獲取 SSLContext 并初始化
            SSLContext sslContext = SSLContext.getInstance("SSL");
            sslContext.init(null, new TrustManager[]{trustManager}, new java.security.SecureRandom());
            // 創(chuàng)建忽略證書的 SSLSocketFactory
            SSLSocketFactory sslSocketFactory = sslContext.getSocketFactory();

            // 構(gòu)建 OkHttpClient
            OkHttpClient.Builder builder = new OkHttpClient.Builder();
            builder.sslSocketFactory(sslSocketFactory, trustManager);
            builder.hostnameVerifier((hostname, session) -> true); // 忽略主機名驗證

            return builder.build();
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }
}

2、windows正常，但發(fā)布生產(chǎn)linux水印亂碼

一般出現(xiàn)此類問題的根源在于linux環(huán)境不存在對應的字體文件。

windows環(huán)境使用下列代碼進行測試即可。

Graphics2D g2d = watermarkedImage.createGraphics();
g2d.drawImage(image, 0, 0, null);
// windows環(huán)境正常
g2d.setFont(new Font("微軟雅黑", isItalic? Font.ITALIC : Font.PLAIN, 30));
g2d.setFont(derivedFont);

但如果需要指定特定的字體文件，可以使用如下寫法。

Graphics2D g2d = watermarkedImage.createGraphics();
g2d.drawImage(image, 0, 0, null);

// linux 環(huán)境指定特定的字體文件
Font customFont = Font.createFont(Font.TRUETYPE_FONT, new File(fontFilePath));
int fontStyle = isItalic? Font.ITALIC : Font.PLAIN;
Font derivedFont = customFont.deriveFont(fontStyle, waterMarkFontSize);

g2d.setFont(derivedFont);

字體文件可以從windows系統(tǒng)的C:\Windows\Fonts中進行拷貝。

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