这期内容当中小编将会给大家带来有关利用JAVA怎么给图片添加水印，文章内容丰富且以专业的角度为大家分析和叙述，阅读完这篇文章希望大家可以有所收获。
印的类型：
单文字水印
单图片水印
多文字水印
多图片水印
水印的开发流程：
创建图片缓存对象
创建Java绘图工具对象
使用绘图工具工具对象将原图绘制到缓存图片对象
使用绘图工具对象将水印（文字/图片）绘制到缓存图片
创建图像编码工具类
使用图像编码工具类，输出缓存图像到目标文件
单文字水印开发
所谓但文字水印，就是在一张图片上添加一条文字水印。其中我们主要的流程是通过ImageIO工具类解码对应的图片，然后创建BufferImage对象，通过BufferImage对象创建Graphics2D对象，再通过Graphics2D对象绘制原图到BufferImage对象。然后，我们还可以使用Graphics2D对象来设置水印的相关信息，如水印内容、字体大小、字体风格等。
这里需要说明的是我们需要计算水印文本的宽度，中文长度即文本宽度，英文长度为文本宽度的二分之一。具体可以参考我源码中的相关内容。
//计算水印文本长度 //1、中文长度即文本长度 2、英文长度为文本长度二分之一 public int getTextLength(String text){ //水印文字长度 int length = text.length(); for (int i = 0; i < text.length(); i++) { String s =String.valueOf(text.charAt(i)); if (s.getBytes().length>1) { length++; } } length = length%2==0?length/2:length/2+1; return length; }//添加单条文字水印方法public String textWaterMark(MultipartFile myFile,String imageFileName) {InputStream is =null;OutputStream os =null;int X = 636;int Y = 700; try { //使用ImageIO解码图片 Image image = ImageIO.read(myFile.getInputStream()); //计算原始图片宽度长度 int width = image.getWidth(null); int height = image.getHeight(null); //创建图片缓存对象 BufferedImage bufferedImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB); //创建java绘图工具对象 Graphics2D graphics2d = bufferedImage.createGraphics(); //参数主要是，原图，坐标，宽高 graphics2d.drawImage(image, 0, 0, width, height, null); graphics2d.setFont(new Font(FONT_NAME, FONT_STYLE, FONT_SIZE)); graphics2d.setColor(FONT_COLOR); //使用绘图工具将水印绘制到图片上 //计算文字水印宽高值 int waterWidth = FONT_SIZE*getTextLength(MARK_TEXT); int waterHeight = FONT_SIZE; //计算水印与原图高宽差 int widthDiff = width-waterWidth; int heightDiff = height-waterHeight; //水印坐标设置 if (X > widthDiff) { X = widthDiff; } if (Y > heightDiff) { Y = heightDiff; } //水印透明设置 graphics2d.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_ATOP, ALPHA)); //纵坐标在下方，不增加字体高度会靠上 graphics2d.drawString(MARK_TEXT, X, Y+FONT_SIZE); graphics2d.dispose(); os = new FileOutputStream(UPLOAD_PATH+"/"+imageFileName); //创建图像编码工具类 JPEGImageEncoder en = JPEGCodec.createJPEGEncoder(os); //使用图像编码工具类，输出缓存图像到目标文件 en.encode(bufferedImage); if(is!=null){ is.close(); } if(os!=null){ os.close(); } } catch (IOException e) { e.printStackTrace(); } return "success"; }单图片水印开发
单图片水印和上面单文字的代码流程大致一致，这里只讲解不同之处。
首先我们需要获得水印图片的路径，然后创建水印文件对象，同样通过ImageIO工具类解码水印图片，中间我们就不需要计算文本长宽了，因为单文字中的长宽即是我们水印图片的长宽。
//水印图片路径 //水印坐标设置 String logoPath = "/img/logo.png"; String realPath = request.getSession().getServletContext().getRealPath(logoPath); File logo = new File(realPath); Image imageLogo = ImageIO.read(logo); int widthLogo = imageLogo.getWidth(null); int heightLogo = imageLogo.getHeight(null); int widthDiff = width-widthLogo; int heightDiff = height-heightLogo; //水印坐标设置 if (X > widthDiff) { X = widthDiff; } if (Y > heightDiff) { Y = heightDiff; } //水印透明设置 graphics2d.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_ATOP, ALPHA)); graphics2d.drawImage(imageLogo, X, Y, null);多文字水印开发
其实多文字水印开发和单文字也是类似的，主要的不同点是我们需要将BufferImage对象进行旋转。因为绘制水印并不支持旋转水印绘制，所以我们需要对原图进行旋转绘制，然后通过循环，我们就可以将一个文字水印多次绘制在原图上了。
//旋转原图，注意旋转角度为弧度制。后面两个参数为旋转的坐标中心 graphics2d.rotate(Math.toRadians(30), bufferedImage.getWidth()/2, bufferedImage.getHeight()/2); int x = -width/2; int y = -height/2; while(x < width*1.5){ y = -height/2; while(y < height*1.5){ graphics2d.drawString(MARK_TEXT, x, y); y+=waterHeight+100; } x+=waterWidth+100; }多图片水印开发
与上文相同，多图片水印需要先读取水印图片，然后对水印设置透明度，在对原图进行旋转，然后通过循环，我们就可以将一个图片水印多次绘制在原图上。
//水印图片路径 String logoPath = "/img/logo.png"; String realPath = request.getSession().getServletContext().getRealPath(logoPath); File logo = new File(realPath); Image imageLogo = ImageIO.read(logo); int widthLogo = imageLogo.getWidth(null); int heightLogo = imageLogo.getHeight(null); //水印透明设置 graphics2d.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_ATOP, ALPHA)); graphics2d.rotate(Math.toRadians(30), bufferedImage.getWidth()/2, bufferedImage.getHeight()/2); int x = -width/2; int y = -height/2; while(x < width*1.5){ y = -height/2; while(y < height*1.5){ graphics2d.drawImage(imageLogo, x, y, null); y+=heightLogo+100; } x+=widthLogo+100; }业务类完整代码：
import java.awt.AlphaComposite;import java.awt.Color;import java.awt.Font;import java.awt.Graphics2D;import java.awt.Image;import java.awt.image.BufferedImage;import java.io.File;import java.io.FileOutputStream;import java.io.IOException;import java.io.InputStream;import java.io.OutputStream;import javax.imageio.ImageIO;import javax.servlet.http.HttpServletRequest;import org.springframework.stereotype.Service;import org.springframework.web.multipart.MultipartFile;import com.allan.service.WaterMarkService;import com.sun.image.codec.jpeg.JPEGCodec;import com.sun.image.codec.jpeg.JPEGImageEncoder;@Servicepublic class WaterMarkServiceImpl implements WaterMarkService{ //定义上传的文件夹 private static final String UPLOAD_PATH = "E:/save"; //定义水印文字样式 private static final String MARK_TEXT = "小卖铺的老爷爷"; private static final String FONT_NAME = "微软雅黑"; private static final int FONT_STYLE = Font.BOLD; private static final int FONT_SIZE = 60; private static final Color FONT_COLOR = Color.black; private static final float ALPHA = 0.3F; //1、上传图片 public String uploadImage(MultipartFile myFile,String imageFileName) { InputStream is =null; OutputStream os =null; try{ is = myFile.getInputStream(); os = new FileOutputStream(UPLOAD_PATH+"/"+imageFileName); byte[] buffer =new byte[1024]; int len = 0; while ((len=is.read(buffer))>0){ os.write(buffer); } }catch(Exception e){ e.printStackTrace(); }finally{ if(is!=null){ try { is.close(); } catch (IOException e) { e.printStackTrace(); } } if(os!=null){ try { os.close(); } catch (IOException e2) { e2.printStackTrace(); } } } return "success"; } //添加单条文字水印 public String textWaterMark(MultipartFile myFile,String imageFileName) { InputStream is =null; OutputStream os =null; int X = 636; int Y = 700; try { Image image = ImageIO.read(myFile.getInputStream()); //计算原始图片宽度长度 int width = image.getWidth(null); int height = image.getHeight(null); //创建图片缓存对象 BufferedImage bufferedImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB); //创建java绘图工具对象 Graphics2D graphics2d = bufferedImage.createGraphics(); //参数主要是，原图，坐标，宽高 graphics2d.drawImage(image, 0, 0, width, height, null); graphics2d.setFont(new Font(FONT_NAME, FONT_STYLE, FONT_SIZE)); graphics2d.setColor(FONT_COLOR); //使用绘图工具将水印绘制到图片上 //计算文字水印宽高值 int waterWidth = FONT_SIZE*getTextLength(MARK_TEXT); int waterHeight = FONT_SIZE; //计算水印与原图高宽差 int widthDiff = width-waterWidth; int heightDiff = height-waterHeight; //水印坐标设置 if (X > widthDiff) { X = widthDiff; } if (Y > heightDiff) { Y = heightDiff; } //水印透明设置 graphics2d.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_ATOP, ALPHA)); graphics2d.drawString(MARK_TEXT, X, Y+FONT_SIZE); graphics2d.dispose(); os = new FileOutputStream(UPLOAD_PATH+"/"+imageFileName); //创建图像编码工具类 JPEGImageEncoder en = JPEGCodec.createJPEGEncoder(os); //使用图像编码工具类，输出缓存图像到目标文件 en.encode(bufferedImage); if(is!=null){ is.close(); } if(os!=null){ os.close(); } } catch (IOException e) { e.printStackTrace(); } return "success"; } //添加单图片水印 public String imageWaterMark(MultipartFile myFile,String imageFileName,HttpServletRequest request) { InputStream is =null; OutputStream os =null; int X = 636; int Y = 763; try { Image image = ImageIO.read(myFile.getInputStream()); //计算原始图片宽度长度 int width = image.getWidth(null); int height = image.getHeight(null); //创建图片缓存对象 BufferedImage bufferedImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB); //创建java绘图工具对象 Graphics2D graphics2d = bufferedImage.createGraphics(); //参数主要是，原图，坐标，宽高 graphics2d.drawImage(image, 0, 0, width, height, null); graphics2d.setFont(new Font(FONT_NAME, FONT_STYLE, FONT_SIZE)); graphics2d.setColor(FONT_COLOR); //水印图片路径 String logoPath = "/img/logo.png"; String realPath = request.getSession().getServletContext().getRealPath(logoPath); File logo = new File(realPath); Image imageLogo = ImageIO.read(logo); int widthLogo = imageLogo.getWidth(null); int heightLogo = imageLogo.getHeight(null); int widthDiff = width-widthLogo; int heightDiff = height-heightLogo; //水印坐标设置 if (X > widthDiff) { X = widthDiff; } if (Y > heightDiff) { Y = heightDiff; } //水印透明设置 graphics2d.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_ATOP, ALPHA)); graphics2d.drawImage(imageLogo, X, Y, null); graphics2d.dispose(); os = new FileOutputStream(UPLOAD_PATH+"/"+imageFileName); //创建图像编码工具类 JPEGImageEncoder en = JPEGCodec.createJPEGEncoder(os); //使用图像编码工具类，输出缓存图像到目标文件 en.encode(bufferedImage); if(is!=null){ is.close(); } if(os!=null){ os.close(); } } catch (IOException e) { e.printStackTrace(); } return "success"; } //添加多条文字水印 public String moreTextWaterMark(MultipartFile myFile,String imageFileName) { InputStream is =null; OutputStream os =null; int X = 636; int Y = 763; try { Image image = ImageIO.read(myFile.getInputStream()); //计算原始图片宽度长度 int width = image.getWidth(null); int height = image.getHeight(null); //创建图片缓存对象 BufferedImage bufferedImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB); //创建java绘图工具对象 Graphics2D graphics2d = bufferedImage.createGraphics(); //参数主要是，原图，坐标，宽高 graphics2d.drawImage(image, 0, 0, width, height, null); graphics2d.setFont(new Font(FONT_NAME, FONT_STYLE, FONT_SIZE)); graphics2d.setColor(FONT_COLOR); //使用绘图工具将水印绘制到图片上 //计算文字水印宽高值 int waterWidth = FONT_SIZE*getTextLength(MARK_TEXT); int waterHeight = FONT_SIZE; //水印透明设置 graphics2d.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_ATOP, ALPHA)); graphics2d.rotate(Math.toRadians(30), bufferedImage.getWidth()/2, bufferedImage.getHeight()/2); int x = -width/2; int y = -height/2; while(x < width*1.5){ y = -height/2; while(y < height*1.5){ graphics2d.drawString(MARK_TEXT, x, y); y+=waterHeight+100; } x+=waterWidth+100; } graphics2d.dispose(); os = new FileOutputStream(UPLOAD_PATH+"/"+imageFileName); //创建图像编码工具类 JPEGImageEncoder en = JPEGCodec.createJPEGEncoder(os); //使用图像编码工具类，输出缓存图像到目标文件 en.encode(bufferedImage); if(is!=null){ is.close(); } if(os!=null){ os.close(); } } catch (IOException e) { e.printStackTrace(); } return "success"; } //多图片水印 public String moreImageWaterMark(MultipartFile myFile,String imageFileName,HttpServletRequest request) { InputStream is =null; OutputStream os =null; int X = 636; int Y = 763; try { Image image = ImageIO.read(myFile.getInputStream()); //计算原始图片宽度长度 int width = image.getWidth(null); int height = image.getHeight(null); //创建图片缓存对象 BufferedImage bufferedImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB); //创建java绘图工具对象 Graphics2D graphics2d = bufferedImage.createGraphics(); //参数主要是，原图，坐标，宽高 graphics2d.drawImage(image, 0, 0, width, height, null); graphics2d.setFont(new Font(FONT_NAME, FONT_STYLE, FONT_SIZE)); graphics2d.setColor(FONT_COLOR); //水印图片路径 String logoPath = "/img/logo.png"; String realPath = request.getSession().getServletContext().getRealPath(logoPath); File logo = new File(realPath); Image imageLogo = ImageIO.read(logo); int widthLogo = imageLogo.getWidth(null); int heightLogo = imageLogo.getHeight(null); //水印透明设置 graphics2d.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_ATOP, ALPHA)); graphics2d.rotate(Math.toRadians(30), bufferedImage.getWidth()/2, bufferedImage.getHeight()/2); int x = -width/2; int y = -height/2; while(x < width*1.5){ y = -height/2; while(y < height*1.5){ graphics2d.drawImage(imageLogo, x, y, null); y+=heightLogo+100; } x+=widthLogo+100; } graphics2d.dispose(); os = new FileOutputStream(UPLOAD_PATH+"/"+imageFileName); //创建图像编码工具类 JPEGImageEncoder en = JPEGCodec.createJPEGEncoder(os); //使用图像编码工具类，输出缓存图像到目标文件 en.encode(bufferedImage); if(is!=null){ is.close(); } if(os!=null){ os.close(); } } catch (IOException e) { e.printStackTrace(); } return "success"; } //计算水印文本长度 //1、中文长度即文本长度 2、英文长度为文本长度二分之一 public int getTextLength(String text){ //水印文字长度 int length = text.length(); for (int i = 0; i < text.length(); i++) { String s =String.valueOf(text.charAt(i)); if (s.getBytes().length>1) { length++; } } length = length%2==0?length/2:length/2+1; return length; }}最后再说明下，本Demo是在上次的文件导入导出的框架基础上编写的，源码中有些其它Demo的代码，主要使用的类有WaterMarkController.java、WaterMarkService.java、WaterMarkServiceImpl.java，因为代码中我是硬编码到E:/save文件夹下的，如果要运行的话，还请先新建此文件夹，或者改为其他文件夹也行。
上述就是小编为大家分享的利用JAVA怎么给图片添加水印了，如果刚好有类似的疑惑，不妨参照上述分析进行理解。如果想知道更多相关知识，欢迎关注编程网行业资讯频道。
