Java用自带的Image IO给图片添加水印

1.  文字水印

import sun.font.fontdesignmetrics;
import javax.imageio.imageio;
import java.awt.*;
import java.awt.image.bufferedimage;
import java.io.file;
import java.io.fileoutputstream;
import java.io.ioexception;
/**
 * @author chengjiansheng
 * @date 2021/6/10
 */
public class watermarkutil
{
    public static void main(string[] args) throws ioexception
        {
            addtext("f:/1.jpeg", "我的梦想是成为火影");
        }
        /**
         * 加文字水印
         * @param srcpath   原文件路径
         * @param content   文字内容
         * @throws ioexception
         */
    public static void addtext(string srcpath, string content) throws ioexception
    {
        //  读取原图片信息
        bufferedimage srcimage = imageio.read(new file(srcpath));
        int width = srcimage.getwidth();
        int height = srcimage.getheight();
        //  创建画笔，设置绘图区域
        bufferedimage bufferedimage = new bufferedimage(width, height, bufferedimage.type_int_rgb);
        graphics2d g = bufferedimage.creategraphics();
        g.drawimage(srcimage, 0, 0, width, height, null);
        //        g.drawimage(srcimage.getscaledinstance(width, height, image.scale_smooth), 0, 0, null);
        g.setfont(new font("宋体", font.plain, 32));
        g.setcolor(color.red);
        //  计算文字长度
        int len = g.getfontmetrics(g.getfont()).charswidth(content.tochararray(), 0, content.length());
        fontdesignmetrics metrics = fontdesignmetrics.getmetrics(g.getfont());
        int len2 = metrics.stringwidth(content);
        system.out.println(len);
        system.out.println(len2);
        //  计算文字坐标
        int x = width - len - 10;
        int y = height - 20;
        //        int x = width - 2 * len;
        //        int y = height - 1 * len;
        g.drawstring(content, x, y);
        g.dispose();
        //  输出文件
        fileoutputstream fos = new fileoutputstream("f:/2.png");
        imageio.write(bufferedimage, "png", fos);
        fos.flush();
        fos.close();
    }
}

可以设置文字透明度

 g.setcomposite(alphacomposite.getinstance(alphacomposite.src_atop, 0.8f)); 

2.  旋转文字

import sun.font.fontdesignmetrics;
import javax.imageio.imageio;
import java.awt.*;
import java.awt.geom.affinetransform;
import java.awt.image.bufferedimage;
import java.io.file;
import java.io.fileoutputstream;
import java.io.ioexception;
/**
 * @author chengjiansheng
 * @date 2021/6/10
 */
public class watermarkutil
{
    // 水印透明度
    private static final float alpha = 0.5 f;
    // 水印文字字体
    private static final font font = new font("宋体", font.bold, 30);
    // 水印文字颜色
    private static final color color = color.red;
    public static void main(string[] args) throws ioexception
        {
            addtext("f:/1.jpeg", "图片由木叶村提供，仅供忍者联军使用！");
        }
        /**
         * 加文字水印
         * @param srcpath   原文件路径
         * @param content   文字内容
         * @throws ioexception
         */
    public static void addtext(string srcpath, string content) throws ioexception
    {
        //  读取原图片信息
        bufferedimage srcimage = imageio.read(new file(srcpath));
        int width = srcimage.getwidth();
        int height = srcimage.getheight();
        //  创建画笔，设置绘图区域
        bufferedimage bufferedimage = new bufferedimage(width, height, bufferedimage.type_int_rgb);
        graphics2d g = bufferedimage.creategraphics();
        g.drawimage(srcimage, 0, 0, width, height, null);
        //        g.drawimage(srcimage.getscaledinstance(width, height, image.scale_smooth), 0, 0, null);
        //  旋转文字
        affinetransform affinetransform = g.gettransform();
        affinetransform.rotate(math.toradians(-30), 0, 0);
        font rotatedfont = font.derivefont(affinetransform);
        g.setfont(rotatedfont); // 字体
        g.setcolor(color); // 颜色
        g.setcomposite(alphacomposite.getinstance(alphacomposite.src_atop, alpha)); // 透明度
        //  计算文字长度
        int len = g.getfontmetrics(g.getfont()).charswidth(content.tochararray(), 0, content.length());
        fontdesignmetrics metrics = fontdesignmetrics.getmetrics(g.getfont());
        int len2 = metrics.stringwidth(content);
        system.out.println(len);
        system.out.println(len2);
        //  计算水印文字坐标
        int x = width / 5;
        int y = height / 3 * 2;
        g.drawstring(content, x, y);
        g.dispose();
        //  输出文件
        fileoutputstream fos = new fileoutputstream("f:/2.png");
        imageio.write(bufferedimage, "png", fos);
        fos.flush();
        fos.close();
    }
}

画矩形框

import sun.font.fontdesignmetrics;
import javax.imageio.imageio;
import java.awt.*;
import java.awt.image.bufferedimage;
import java.io.file;
import java.io.fileoutputstream;
import java.io.ioexception;
/**
 * @author chengjiansheng
 * @date 2021/6/10
 */
public class watermarkutil
{
    // 水印透明度
    private static final float alpha = 0.5 f;
    // 水印文字字体
    private static final font font = new font("宋体", font.bold, 30);
    // 水印文字颜色
    private static final color color = color.red;
    public static void main(string[] args) throws ioexception
        {
            addtext("f:/1.jpeg", "图片由木叶村提供，仅供忍者联军使用！");
        }
        /**
         * 加文字水印
         * @param srcpath   原文件路径
         * @param content   文字内容
         * @throws ioexception
         */
    public static void addtext(string srcpath, string content) throws ioexception
    {
        //  读取原图片信息
        bufferedimage srcimage = imageio.read(new file(srcpath));
        int width = srcimage.getwidth();
        int height = srcimage.getheight();
        //  创建画笔，设置绘图区域
        bufferedimage bufferedimage = new bufferedimage(width, height, bufferedimage.type_int_rgb);
        graphics2d g = bufferedimage.creategraphics();
        g.drawimage(srcimage, 0, 0, width, height, null);
        g.setfont(font); // 字体
        g.setcolor(color); // 颜色
        g.setcomposite(alphacomposite.getinstance(alphacomposite.src_atop, alpha)); // 透明度
        //  计算文字宽高度
        fontdesignmetrics metrics = fontdesignmetrics.getmetrics(font);
        int textwidth = metrics.stringwidth(content); //  文字宽度
        int textheight = metrics.getheight(); //  文字高度
        //  计算文字坐标
        int x = (width - textwidth) / 2;
        int y = (height + textheight) / 2;
        //  写文字
        g.drawstring(content, x, y);
        //  画矩形
        int padding = 10; // 内边距
        g.drawrect(x - padding / 2, y - textheight, textwidth + padding, textheight + padding);
        g.dispose();
        //  输出文件
        fileoutputstream fos = new fileoutputstream("f:/2.png");
        imageio.write(bufferedimage, "png", fos);
        fos.flush();
        fos.close();
    }
}

3.  旋转坐标轴

import sun.font.fontdesignmetrics;
import javax.imageio.imageio;
import java.awt.*;
import java.awt.image.bufferedimage;
import java.io.file;
import java.io.fileoutputstream;
import java.io.ioexception;
/**
 * @author chengjiansheng
 * @date 2021/6/10
 */
public class watermarkutil
{
    // 水印透明度
    private static final float alpha = 0.5 f;
    // 水印文字字体
    private static final font font = new font("宋体", font.bold, 30);
    // 水印文字颜色
    private static final color color = color.red;
    public static void main(string[] args) throws ioexception
        {
            addtext("f:/1.jpeg", "图片由木叶村提供，仅供忍者联军使用！");
        }
        /**
         * 加文字水印
         * @param srcpath   原文件路径
         * @param content   文字内容
         * @throws ioexception
         */
    public static void addtext(string srcpath, string content) throws ioexception
    {
        //  读取原图片信息
        bufferedimage srcimage = imageio.read(new file(srcpath));
        int width = srcimage.getwidth();
        int height = srcimage.getheight();
        //  创建画笔，设置绘图区域
        bufferedimage bufferedimage = new bufferedimage(width, height, bufferedimage.type_int_rgb);
        graphics2d g = bufferedimage.creategraphics();
        g.drawimage(srcimage, 0, 0, width, height, null);
        g.setfont(font); // 字体
        g.setcolor(color); // 颜色
        g.setcomposite(alphacomposite.getinstance(alphacomposite.src_atop, alpha)); // 透明度
        //  计算文字宽高度
        fontdesignmetrics metrics = fontdesignmetrics.getmetrics(font);
        int textwidth = metrics.stringwidth(content); //  文字宽度
        int textheight = metrics.getheight(); //  文字高度
        //  旋转坐标轴
        g.translate(-width / 5, height / 4);
        g.rotate(-30 * math.pi / 180);
        //  计算文字坐标
        int x = (width - textwidth) / 2;
        int y = (height + textheight) / 2;
        //  写文字
        g.drawstring(content, x, y);
        //  画矩形
        int padding = 10; // 内边距
        g.drawrect(x - padding / 2, y - textheight, textwidth + padding, textheight + padding);
        g.dispose();
        //  输出文件
        fileoutputstream fos = new fileoutputstream("f:/2.png");
        imageio.write(bufferedimage, "png", fos);
        fos.flush();
        fos.close();
    }
}

结合下载功能，完整的代码如下：

/**
 * 下载
 */
@
getmapping("/download")
public void download(@requestparam("mediaid") string mediaid, httpservletrequest request, httpservletresponse response) throws ioexception
{
    sysfile sysfile = sysfileservice.getbymediaid(mediaid);
    if(null == sysfile)
    {
        throw new illegalargumentexception("文件不存在");
    }
    string mimetype = request.getservletcontext().getmimetype(sysfile.getpath());
    system.out.println(mimetype);
    response.setcontenttype(sysfile.getcontenttype());
    response.setheader(httpheaders.content_disposition, "attachment;filename=" + urlencoder.encode(sysfile.getoriginalfilename(), "utf-8"));
    //        fileinputstream fis = new fileinputstream(sysfile.getpath());
    servletoutputstream sos = response.getoutputstream();
    watermarkutil.addtext(sysfile.getpath(), "哈哈哈哈", sos);
    //        ioutils.copy(fis, sos);
    //        ioutils.closequietly(fis);
    ioutils.closequietly(sos);
}

import sun.font.fontdesignmetrics;
import javax.imageio.imageio;
import java.awt.*;
import java.awt.image.bufferedimage;
import java.io.file;
import java.io.ioexception;
import java.io.outputstream;
/**
 * @author chengjiansheng
 * @date 2021/6/10
 */
public class watermarkutil
{
    // 水印透明度
    private static final float alpha = 0.5 f;
    // 水印文字字体
    private static final font font = new font("宋体", font.bold, 30);
    // 水印文字颜色
    private static final color color = color.red;
    /**
     * 加文字水印
     * @param srcpath   原文件路径
     * @param content   文字内容
     * @throws ioexception
     */
    public static void addtext(string srcpath, string content, outputstream outputstream) throws ioexception
    {
        //  读取原图片信息
        bufferedimage srcimage = imageio.read(new file(srcpath));
        int width = srcimage.getwidth();
        int height = srcimage.getheight();
        //  画板
        bufferedimage bufferedimage = new bufferedimage(width, height, bufferedimage.type_int_rgb);
        //  画笔
        graphics2d g = bufferedimage.creategraphics();
        g.drawimage(srcimage, 0, 0, width, height, null);
        g.setfont(font); // 字体
        g.setcolor(color); // 颜色
        g.setcomposite(alphacomposite.getinstance(alphacomposite.src_atop, alpha)); // 透明度
        //  计算文字宽高度
        fontdesignmetrics metrics = fontdesignmetrics.getmetrics(font);
        int textwidth = metrics.stringwidth(content); //  文字宽度
        int textheight = metrics.getheight(); //  文字高度
        //  旋转坐标轴
        g.translate(-width / 5, height / 4);
        g.rotate(-30 * math.pi / 180);
        //  计算文字坐标
        int x = (width - textwidth) / 2;
        int y = (height + textheight) / 2;
        //  写文字
        g.drawstring(content, x, y);
        //  画矩形
        int padding = 10; // 内边距
        g.drawrect(x - padding / 2, y - textheight, textwidth + padding, textheight + padding);
        g.dispose();
        //  输出
        imageio.write(bufferedimage, "png", outputstream);
    }
}

另外的写法

import javax.imageio.imageio;
import java.awt.*;
import java.awt.image.bufferedimage;
import java.io.file;
import java.io.fileoutputstream;

/**
 * @projectname: test
 * @package: com.test.utils
 * @classname: mytest
 * @author: luqiming
 * @description:
 * @date: 2020/10/29 11:48
 * @version: 1.0
 */
public class addwatermarkutil {
    public static void waterpress(string srcimgpath, string outimgpath,
                           color markcontentcolor, int fontsize, string watermarkcontent) {
        try {
            string[] watermarkcontents = watermarkcontent.split("\\|\\|");
            // 读取原图片信息
            file srcimgfile = new file(srcimgpath);
            image srcimg = imageio.read(srcimgfile);
            int srcimgwidth = srcimg.getwidth(null);
            int srcimgheight = srcimg.getheight(null);
            // 加水印
            bufferedimage bufimg = new bufferedimage(srcimgwidth, srcimgheight, bufferedimage.type_int_rgb);
            // 得到画笔对象
            graphics2d g = bufimg.creategraphics();
            // 设置起点
            g.drawimage(srcimg, 0, 0, srcimgwidth, srcimgheight, null);
            font font = new font("宋体", font.plain, fontsize);
            // 根据图片的背景设置水印颜色
            g.setcolor(markcontentcolor);
            // 设置水印文字字体
            g.setfont(font);
            // 数组长度
            int contentlength = watermarkcontents.length;
            // 获取水印文字中最长的
            int maxlength = 0;
            for (int i = 0; i < contentlength; i++) {
                int fontlen = getwatermarklength(watermarkcontents[i], g);
                if (maxlength < fontlen) {
                    maxlength = fontlen;
                }
            }

            for (int j = 0; j < contentlength; j++) {
                watermarkcontent = watermarkcontents[j];
                int tempx = 10;
                int tempy = fontsize;
                // 单字符长度
                int tempcharlen = 0;
                // 单行字符总长度临时计算
                int templinelen = 0;
                stringbuffer sb = new stringbuffer();
                for (int i = 0; i < watermarkcontent.length(); i++) {
                    char tempchar = watermarkcontent.charat(i);
                    tempcharlen = getcharlen(tempchar, g);
                    templinelen += tempcharlen;
                    if (templinelen >= srcimgwidth) {
                        // 长度已经满一行,进行文字叠加
                        g.drawstring(sb.tostring(), tempx, tempy);
                        // 清空内容,重新追加
                        sb.delete(0, sb.length());
                        templinelen = 0;
                    }
                    // 追加字符
                    sb.append(tempchar);
                }
                // 通过设置后两个输入参数给水印定位
                g.drawstring(sb.tostring(), 20, srcimgheight - (contentlength - j - 1) * tempy-50);
            }
            g.dispose();

            // 输出图片
            fileoutputstream outimgstream = new fileoutputstream(outimgpath);
            imageio.write(bufimg, "jpg", outimgstream);
            outimgstream.flush();
            outimgstream.close();
        } catch (exception e) {
            e.printstacktrace();
        }
    }

    public static int getcharlen(char c, graphics2d g) {
        return g.getfontmetrics(g.getfont()).charwidth(c);
    }

    /**
     * 获取水印文字总长度
     *
     * @paramwatermarkcontent水印的文字
     * @paramg
     * @return水印文字总长度
     */
    public static int getwatermarklength(string watermarkcontent, graphics2d g) {
        return g.getfontmetrics(g.getfont()).charswidth(
                watermarkcontent.tochararray(), 0, watermarkcontent.length());
    }


    public static void main(string[] args) {
        // 原图位置, 输出图片位置, 水印文字颜色, 水印文字
        string font = "张天爱||就很完美||2020-05-27 17:00:00";
        string inputaddress = "f:/upupoowallpaper/1.jpg";
        string outputaddress = "f:/upupoowallpaper/1.jpg";
        color color = color.green;
        waterpress(inputaddress, outputaddress, color, 50, font);
    }
}

添加效果

关于水印位置，需要修改：

//左下角
 g.drawstring(sb.tostring(), 0, srcimgheight - (contentlength - j - 1) * tempy);

//右下角
 g.drawstring(sb.tostring(), srcimgwidth - maxlength, srcimgheight - (contentlength - j - 1) * tempy);

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