前言：在做网站的时候经常用的功能就是，用户上传图片对自己上传的图片进行截图，DIV自己的头像。或者上传幻灯片大图进行DIV设置小图。
解决方案：目前我知道的解决方案有两个如下：
一、flash用户上传头像组件 ，地址： http://www.hdfu.net/index.html （但收费）
二、jq插件imgAreaSelect， 地址：http://odyniec.net/projects/imgareaselect/
注：官网文档为英文的，如果想看中文的这里也有，http://www.jb51.net/article/28485.htm（不一定定保证是最新的）
说了这么多先看看效果吧
直接上代码:
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>imgAreaSelect图片截图</title>
<script type="text/javascript" src="imgareaselect/scripts/jquery.min.js"></script>
<script type="text/javascript" src="swfupload/swfupload.js"></script>
<script type="text/javascript" src="imgareaselect/scripts/jquery.imgareaselect.pack.js"></script>
<link href="css/style.css" rel="stylesheet" type="text/css"/>
<link href="css/default.css" rel="stylesheet" type="text/css"/>
<link href="imgareaselect/css/imgareaselect-default.css" rel="stylesheet" type="text/css"/>
<script type="text/javascript">
$(function () {
//回调方法
function preview(img, selection) {
if (!selection.width || !selection.height)
return; var scaleX = 100 / selection.width;
var scaleY = 100 / selection.height; $('#preview img').css({
width: Math.round(scaleX * 300),
height: Math.round(scaleY * 300),
marginLeft: -Math.round(scaleX * selection.x1),
marginTop: -Math.round(scaleY * selection.y1)
}); //完成后对表单进行赋值
$('input[name="x1"]').val(selection.x1);
$('input[name="y1"]').val(selection.y1);
$('input[name="x2"]').val(selection.x2);
$('input[name="y2"]').val(selection.y2);
$('input[name="path"]').val($('img#photo').attr("src")); $('#x1').val(selection.x1);
$('#y1').val(selection.y1);
$('#x2').val(selection.x2);
$('#y2').val(selection.y2);
$('#w').val(selection.width);
$('#h').val(selection.height); $('#btn').show();
} $('#photo').imgAreaSelect({
aspectRatio: '1:1', //设置区域的比例
handles: true, //设置区域的四角显示
fadeSpeed: 200, //动画效果时间
onSelectChange: preview //选择完成后调用的方法
}); //表单提交事件
$('#btn').click(function () {
if ($('#x1').val() == '') {
alert('还没有进行截图');
return;
}
$.ajax({
type: 'POST',
url: '/uploadarea?operate=2',
data: $('#dataForm').serialize(),
dataType: 'json',
cache: false,
success: function (data) {
if (data.success) {
var imgLi = $("<li></li>");
var newImg = $('<div" class=\"img_box ' + '">' +
'<img src="' + data.imgs + '" />').appendTo(imgLi);
$("#show_list ul").append(imgLi);
}
}
});
});
});
</script>
</head>
<body>
<h2 style="text-align: center">截图演示</h2> <div class="container demo">
<div style="float: left; width: 50%;">
<p class="instructions">
点击这里，选择截图区域，<font color="red">必须为等比例图片</font>
</p> <div class="frame" style="margin: 0 0.3em; width: 300px; height: 300px;">
<img id="photo" src="img/605.jpg">
</div>
</div> <div style="float: left; width: 50%;">
<p style="font-size: 110%; font-weight: bold; padding-left: 0.1em;">
选择区域预览
</p> <div class="frame" style="margin: 0 1em; width: 100px; height: 100px;">
<div id="preview" style="width: 100px; height: 100px; overflow: hidden;">
<img src="img/605.jpg" style="width: 100px; height: 100px;">
</div>
</div>
<%--表单数据--%>
<form id="dataForm" style="position: absolute;top:25%;left:60%;">
<input type="hidden" name="x1" value=""/>
<input type="hidden" name="y1" value=""/>
<input type="hidden" name="x2" value=""/>
<input type="hidden" name="y2" value=""/>
<input type="hidden" name="path"/>
<input type="button" id="btn" style="display: none;" value="进行截图"/>
</form> <table style="margin-top: 1em;">
<thead>
<tr>
<th colspan="2" style="font-size: 110%; font-weight: bold; text-align: left; padding-left: 0.1em;">
坐标
</th>
<th colspan="2" style="font-size: 110%; font-weight: bold; text-align: left; padding-left: 0.1em;">
尺寸
</th>
</tr>
</thead>
<tbody>
<tr>
<td style="width: 10%;"><b>X<sub>1</sub>:</b></td>
<td style="width: 30%;"><input type="text" id="x1" value="-"></td>
<td style="width: 20%;"><b>Width:</b></td>
<td><input type="text" value="-" id="w"></td>
</tr>
<tr>
<td><b>Y<sub>1</sub>:</b></td>
<td><input type="text" id="y1" value="-"></td>
<td><b>Height:</b></td>
<td><input type="text" id="h" value="-"></td>
</tr>
<tr>
<td><b>X<sub>2</sub>:</b></td>
<td><input type="text" id="x2" value="-"></td>
<td></td>
<td></td>
</tr>
<tr>
<td><b>Y<sub>2</sub>:</b></td>
<td><input type="text" id="y2" value="-"></td>
<td></td>
<td></td>
</tr>
</tbody>
</table>
</div>
</div>
<div style="margin: 0 auto;width:960px;">
<h3>所得截图</h3> <div id="show_list">
<ul> </ul>
</div>
</div>
</body>
</html>
上传的Servlet代码：
package com.zxd.tool; import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload; import javax.jws.WebService;
import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.File;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.List;
import java.util.UUID; /**
* 图片上传后进行，处理的裁剪类
*
* @author 张晓东
*/
@WebServlet("/uploadarea")
public class UploadArea extends HttpServlet {
private File tempDir; //临时路径
private File saveDir; //保存路径
private File cutDir; //裁剪图片保存的路径 /**
* servlet初始化事件
*
* @param config
* @throws ServletException
*/
public void init(ServletConfig config) throws ServletException {
String uploadPath = config.getServletContext().getRealPath("/");
StringBuffer sb = new StringBuffer(uploadPath);
saveDir = new File(sb.append("\\upload").toString());
tempDir = new File(sb.append("\\temp").toString());
cutDir = new File(uploadPath + "\\upload\\cut");
if (!saveDir.exists()) {
saveDir.mkdir();
}
if (!tempDir.exists()) {
tempDir.mkdir();
}
if (!cutDir.exists()) {
cutDir.mkdir();
} } protected void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException {
this.doPost(request, response);
} public void doPost(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException {
int operate = request.getParameter("operate").isEmpty() ? 0 : Integer.valueOf(request.getParameter("operate")); //方法操作
switch (operate) {
case 1: //上传操作
uploadImg(request, response);
break;
case 2: //截图操作
cutImg(request, response);
break;
}
} //上传图片
private void uploadImg(HttpServletRequest request, HttpServletResponse response) throws IOException {
DiskFileItemFactory factory = new DiskFileItemFactory();
factory.setSizeThreshold(1 * 1024 * 1024); //设置缓冲区大小
factory.setRepository(tempDir); //设置临时保存目录
ServletFileUpload sfu = new ServletFileUpload(factory); //Servelt文件上传对象
sfu.setFileSizeMax(200 * 1024 * 1024); //200M 文件上传大小
sfu.setHeaderEncoding("utf-8");
List<FileItem> list = null;
try {
list = sfu.parseRequest(request); //得到文件
} catch (FileUploadException e) {
e.printStackTrace();
}
int size = list.size();
StringBuffer json = new StringBuffer("{\"success\":true,\"imgs\":["); //输出到页面的json
PrintWriter out = response.getWriter();
for (int i = 0; i < size; i++) { //循环保存文件
FileItem file = list.get(i);
if (file.isFormField()) { //如果是表单字段
String name = file.getFieldName(); // 获得该字段名称
String value = file.getString("utf-8"); //获得该字段值
} else {
String extName = file.getName().substring( //得到扩展名
file.getName().lastIndexOf("."));
String fname = UUID.randomUUID() + extName;
try {
file.write(new File(saveDir, fname)); // 写入文件
String path = request.getSession().getServletContext().getRealPath("/");
if (i == size) {
json.append(saveDir.toString() + "\\" + fname + "]}"); //回传上传图片路径
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
out.flush();
out.print(json);
out.close();
} //裁剪图片
private void cutImg(HttpServletRequest request, HttpServletResponse response) throws IOException {
StringBuffer json = new StringBuffer("{\"success\":true,\"imgs\":"); //输出到页面的json
response.setContentType("text/plain;charset=utf-8");
response.setCharacterEncoding("utf-8");
//得到坐标
Integer x1 = Integer.parseInt(request.getParameter("x1"));
Integer y1 = Integer.parseInt(request.getParameter("y1"));
Integer x2 = Integer.parseInt(request.getParameter("x2"));
Integer y2 = Integer.parseInt(request.getParameter("y2"));
String basePath = request.getSession().getServletContext().getRealPath("/"); //项目物理路径
String path = request.getParameter("path"); //原图片路径
String extName = path.substring(path.lastIndexOf(".")); //文件扩展名
int width = x2 - x1; //图像的宽度
int height = y2 - y1;//图像的高度
String cutFileName ="\\cut_" + UUID.randomUUID() + extName;
ImageUtils.cut(basePath + "\\" + path, cutDir.toString() + cutFileName, x1, y1, width, height);
json.append("\"upload\\\\cut\\"+cutFileName+"\"}");
PrintWriter out = response.getWriter();
out.flush();
out.print(json);
out.close(); }
}
ImagesUtils.java
package com.zxd.tool; /**
* Created by zhang on 14-3-1.
* 图片的常用操作类
*/ import java.awt.AlphaComposite;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.Toolkit;
import java.awt.color.ColorSpace;
import java.awt.geom.AffineTransform;
import java.awt.image.AffineTransformOp;
import java.awt.image.BufferedImage;
import java.awt.image.ColorConvertOp;
import java.awt.image.CropImageFilter;
import java.awt.image.FilteredImageSource;
import java.awt.image.ImageFilter;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO; /**
* 图片处理工具类：<br>
* 功能：缩放图像、切割图像、图像类型转换、彩色转黑白、文字水印、图片水印等
*
* @author Administrator
*/
public class ImageUtils {
/**
* 几种常见的图片格式
*/
public static String IMAGE_TYPE_GIF = "gif";// 图形交换格式
public static String IMAGE_TYPE_JPG = "jpg";// 联合照片专家组
public static String IMAGE_TYPE_JPEG = "jpeg";// 联合照片专家组
public static String IMAGE_TYPE_BMP = "bmp";// 英文Bitmap（位图）的简写，它是Windows操作系统中的标准图像文件格式
public static String IMAGE_TYPE_PNG = "png";// 可移植网络图形
public static String IMAGE_TYPE_PSD = "psd";// Photoshop的专用格式Photoshop /**
* 缩放图像（按比例缩放）
*
* @param srcImageFile 源图像文件地址(绝对路径)
* @param result 缩放后的图像地址(绝对路径)
* @param scale 缩放比例
* @param flag 缩放选择:true 放大; false 缩小;
*/
public final static void scale(String srcImageFile, String result,
int scale, boolean flag) {
try {
BufferedImage src = ImageIO.read(new File(srcImageFile)); // 读入文件
int width = src.getWidth(); // 得到源图宽
int height = src.getHeight(); // 得到源图长
if (flag) {// 放大
width = width * scale;
height = height * scale;
} else {// 缩小
width = width / scale;
height = height / scale;
}
Image image = src.getScaledInstance(width, height,
Image.SCALE_DEFAULT);
BufferedImage tag = new BufferedImage(width, height,
BufferedImage.TYPE_INT_RGB);
Graphics g = tag.getGraphics();
g.drawImage(image, 0, 0, null); // 绘制缩小后的图
g.dispose();
ImageIO.write(tag, "JPEG", new File(result));// 输出到文件流
} catch (IOException e) {
e.printStackTrace();
}
} /**
* 缩放图像（按高度和宽度缩放）
*
* @param srcImageFile 源图像文件地址(绝对路径)
* @param result 缩放后的图像地址(绝对路径)
* @param height 缩放后的高度
* @param width 缩放后的宽度
* @param bb 比例不对时是否需要补白：true为补白; false为不补白;
*/
public final static void scale2(String srcImageFile, String result, int height, int width, boolean bb) {
try {
double ratio = 0.0; // 缩放比例
File f = new File(srcImageFile);
BufferedImage bi = ImageIO.read(f);
Image itemp = bi.getScaledInstance(width, height, bi.SCALE_SMOOTH);
// 计算比例
if ((bi.getHeight() > height) || (bi.getWidth() > width)) {
if (bi.getHeight() > bi.getWidth()) {
ratio = (new Integer(height)).doubleValue()
/ bi.getHeight();
} else {
ratio = (new Integer(width)).doubleValue() / bi.getWidth();
}
AffineTransformOp op = new AffineTransformOp(AffineTransform
.getScaleInstance(ratio, ratio), null);
itemp = op.filter(bi, null);
}
if (bb) {//补白
BufferedImage image = new BufferedImage(width, height,
BufferedImage.TYPE_INT_RGB);
Graphics2D g = image.createGraphics();
g.setColor(Color.white);
g.fillRect(0, 0, width, height);
if (width == itemp.getWidth(null))
g.drawImage(itemp, 0, (height - itemp.getHeight(null)) / 2,
itemp.getWidth(null), itemp.getHeight(null),
Color.white, null);
else
g.drawImage(itemp, (width - itemp.getWidth(null)) / 2, 0,
itemp.getWidth(null), itemp.getHeight(null),
Color.white, null);
g.dispose();
itemp = image;
}
ImageIO.write((BufferedImage) itemp, "JPEG", new File(result));
} catch (IOException e) {
e.printStackTrace();
}
} /**
* 图像切割(按指定起点坐标和宽高切割)
*
* @param srcImageFile 源图像地址 (绝对路径)
* @param result 切片后的图像地址 (绝对路径)
* @param x 目标切片起点坐标X
* @param y 目标切片起点坐标Y
* @param width 目标切片宽度
* @param height 目标切片高度
*/
public final static void cut(String srcImageFile, String result,
int x, int y, int width, int height) {
try {
// 读取源图像
BufferedImage bi = ImageIO.read(new File(srcImageFile));
int srcWidth = bi.getHeight(); // 源图宽度
int srcHeight = bi.getWidth(); // 源图高度
if (srcWidth > 0 && srcHeight > 0) {
Image image = bi.getScaledInstance(srcWidth, srcHeight,
Image.SCALE_DEFAULT);
// 四个参数分别为图像起点坐标和宽高
// 即: CropImageFilter(int x,int y,int width,int height)
ImageFilter cropFilter = new CropImageFilter(x, y, width, height);
Image img = Toolkit.getDefaultToolkit().createImage(
new FilteredImageSource(image.getSource(),
cropFilter));
BufferedImage tag = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
Graphics g = tag.getGraphics();
g.drawImage(img, 0, 0, width, height, null); // 绘制切割后的图
g.dispose();
// 输出为文件
ImageIO.write(tag, "JPEG", new File(result));
}
} catch (Exception e) {
e.printStackTrace();
}
} /**
* 图像切割（指定切片的行数和列数）
*
* @param srcImageFile 源图像地址 (绝对路径)
* @param descDir 切片目标文件夹
* @param rows 目标切片行数。默认2，必须是范围 [1, 20] 之内
* @param cols 目标切片列数。默认2，必须是范围 [1, 20] 之内
*/
public final static void cut2(String srcImageFile, String descDir,
int rows, int cols) {
try {
if (rows <= 0 || rows > 20) rows = 2; // 切片行数
if (cols <= 0 || cols > 20) cols = 2; // 切片列数
// 读取源图像
BufferedImage bi = ImageIO.read(new File(srcImageFile));
int srcWidth = bi.getHeight(); // 源图宽度
int srcHeight = bi.getWidth(); // 源图高度
if (srcWidth > 0 && srcHeight > 0) {
Image img;
ImageFilter cropFilter;
Image image = bi.getScaledInstance(srcWidth, srcHeight, Image.SCALE_DEFAULT);
int destWidth = srcWidth; // 每张切片的宽度
int destHeight = srcHeight; // 每张切片的高度
// 计算切片的宽度和高度
if (srcWidth % cols == 0) {
destWidth = srcWidth / cols;
} else {
destWidth = (int) Math.floor(srcWidth / cols) + 1;
}
if (srcHeight % rows == 0) {
destHeight = srcHeight / rows;
} else {
destHeight = (int) Math.floor(srcWidth / rows) + 1;
}
// 循环建立切片
// 改进的想法:是否可用多线程加快切割速度
for (int i = 0; i < rows; i++) {
for (int j = 0; j < cols; j++) {
// 四个参数分别为图像起点坐标和宽高
// 即: CropImageFilter(int x,int y,int width,int height)
cropFilter = new CropImageFilter(j * destWidth, i * destHeight,
destWidth, destHeight);
img = Toolkit.getDefaultToolkit().createImage(
new FilteredImageSource(image.getSource(),
cropFilter));
BufferedImage tag = new BufferedImage(destWidth,
destHeight, BufferedImage.TYPE_INT_RGB);
Graphics g = tag.getGraphics();
g.drawImage(img, 0, 0, null); // 绘制缩小后的图
g.dispose();
// 输出为文件
ImageIO.write(tag, "JPEG", new File(descDir
+ "_r" + i + "_c" + j + ".jpg"));
}
}
}
} catch (Exception e) {
e.printStackTrace();
}
} /**
* 图像切割（指定切片的宽度和高度）
*
* @param srcImageFile 源图像地址 (绝对路径)
* @param descDir 切片目标文件夹
* @param destWidth 目标切片宽度。默认200
* @param destHeight 目标切片高度。默认150
*/
public final static void cut3(String srcImageFile, String descDir,
int destWidth, int destHeight) {
try {
if (destWidth <= 0) destWidth = 200; // 切片宽度
if (destHeight <= 0) destHeight = 150; // 切片高度
// 读取源图像
BufferedImage bi = ImageIO.read(new File(srcImageFile));
int srcWidth = bi.getHeight(); // 源图宽度
int srcHeight = bi.getWidth(); // 源图高度
if (srcWidth > destWidth && srcHeight > destHeight) {
Image img;
ImageFilter cropFilter;
Image image = bi.getScaledInstance(srcWidth, srcHeight, Image.SCALE_DEFAULT);
int cols = 0; // 切片横向数量
int rows = 0; // 切片纵向数量
// 计算切片的横向和纵向数量
if (srcWidth % destWidth == 0) {
cols = srcWidth / destWidth;
} else {
cols = (int) Math.floor(srcWidth / destWidth) + 1;
}
if (srcHeight % destHeight == 0) {
rows = srcHeight / destHeight;
} else {
rows = (int) Math.floor(srcHeight / destHeight) + 1;
}
// 循环建立切片
// 改进的想法:是否可用多线程加快切割速度
for (int i = 0; i < rows; i++) {
for (int j = 0; j < cols; j++) {
// 四个参数分别为图像起点坐标和宽高
// 即: CropImageFilter(int x,int y,int width,int height)
cropFilter = new CropImageFilter(j * destWidth, i * destHeight,
destWidth, destHeight);
img = Toolkit.getDefaultToolkit().createImage(
new FilteredImageSource(image.getSource(),
cropFilter));
BufferedImage tag = new BufferedImage(destWidth,
destHeight, BufferedImage.TYPE_INT_RGB);
Graphics g = tag.getGraphics();
g.drawImage(img, 0, 0, null); // 绘制缩小后的图
g.dispose();
// 输出为文件
ImageIO.write(tag, "JPEG", new File(descDir
+ "_r" + i + "_c" + j + ".jpg"));
}
}
}
} catch (Exception e) {
e.printStackTrace();
}
} /**
* 图像类型转换：GIF->JPG、GIF->PNG、PNG->JPG、PNG->GIF(X)、BMP->PNG
*
* @param srcImageFile 源图像地址 (绝对路径)
* @param formatName 包含格式非正式名称的 String：如JPG、JPEG、GIF等
* @param destImageFile 目标图像地址 (绝对路径)
*/
public final static void convert(String srcImageFile, String formatName, String destImageFile) {
try {
File f = new File(srcImageFile);
f.canRead();
f.canWrite();
BufferedImage src = ImageIO.read(f);
ImageIO.write(src, formatName, new File(destImageFile));
} catch (Exception e) {
e.printStackTrace();
}
} /**
* 彩色转为黑白
*
* @param srcImageFile 源图像地址 (绝对路径)
* @param destImageFile 目标图像地址 (绝对路径)
*/
public final static void gray(String srcImageFile, String destImageFile) {
try {
BufferedImage src = ImageIO.read(new File(srcImageFile));
ColorSpace cs = ColorSpace.getInstance(ColorSpace.CS_GRAY);
ColorConvertOp op = new ColorConvertOp(cs, null);
src = op.filter(src, null);
ImageIO.write(src, "JPEG", new File(destImageFile));
} catch (IOException e) {
e.printStackTrace();
}
} /**
* 给图片添加文字水印
*
* @param pressText 水印文字
* @param srcImageFile 源图像地址 (绝对路径)
* @param destImageFile 目标图像地址 (绝对路径)
* @param fontName 水印的字体名称
* @param fontStyle 水印的字体样式
* @param color 水印的字体颜色
* @param fontSize 水印的字体大小
* @param x 修正值
* @param y 修正值
* @param alpha 透明度：alpha 必须是范围 [0.0, 1.0] 之内（包含边界值）的一个浮点数字
*/
public final static void pressText(String pressText,
String srcImageFile, String destImageFile, String fontName,
int fontStyle, Color color, int fontSize, int x,
int y, float alpha) {
try {
File img = new File(srcImageFile);
Image src = ImageIO.read(img);
int width = src.getWidth(null);
int height = src.getHeight(null);
BufferedImage image = new BufferedImage(width, height,
BufferedImage.TYPE_INT_RGB);
Graphics2D g = image.createGraphics();
g.drawImage(src, 0, 0, width, height, null);
g.setColor(color);
g.setFont(new Font(fontName, fontStyle, fontSize));
g.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_ATOP,
alpha));
// 在指定坐标绘制水印文字
g.drawString(pressText, (width - (getLength(pressText) * fontSize))
/ 2 + x, (height - fontSize) / 2 + y);
g.dispose();
ImageIO.write((BufferedImage) image, "JPEG", new File(destImageFile));// 输出到文件流
} catch (Exception e) {
e.printStackTrace();
}
} /**
* 给图片添加文字水印
*
* @param pressText 水印文字
* @param srcImageFile 源图像地址 (绝对路径)
* @param destImageFile 目标图像地址 (绝对路径)
* @param fontName 字体名称
* @param fontStyle 字体样式
* @param color 字体颜色
* @param fontSize 字体大小
* @param x 修正值
* @param y 修正值
* @param alpha 透明度：alpha 必须是范围 [0.0, 1.0] 之内（包含边界值）的一个浮点数字
*/
public final static void pressText2(String pressText, String srcImageFile, String destImageFile,
String fontName, int fontStyle, Color color, int fontSize, int x,
int y, float alpha) {
try {
File img = new File(srcImageFile);
Image src = ImageIO.read(img);
int width = src.getWidth(null);
int height = src.getHeight(null);
BufferedImage image = new BufferedImage(width, height,
BufferedImage.TYPE_INT_RGB);
Graphics2D g = image.createGraphics();
g.drawImage(src, 0, 0, width, height, null);
g.setColor(color);
g.setFont(new Font(fontName, fontStyle, fontSize));
g.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_ATOP,
alpha));
// 在指定坐标绘制水印文字
g.drawString(pressText, (width - (getLength(pressText) * fontSize))
/ 2 + x, (height - fontSize) / 2 + y);
g.dispose();
ImageIO.write((BufferedImage) image, "JPEG", new File(destImageFile));
} catch (Exception e) {
e.printStackTrace();
}
} /**
* 给图片添加图片水印
*
* @param pressImg 水印图片 (绝对路径)
* @param srcImageFile 源图像地址 (绝对路径)
* @param destImageFile 目标图像地址 (绝对路径)
* @param x 修正值。 默认在中间
* @param y 修正值。 默认在中间
* @param alpha 透明度：alpha 必须是范围 [0.0, 1.0] 之内（包含边界值）的一个浮点数字
*/
public final static void pressImage(String pressImg, String srcImageFile, String destImageFile,
int x, int y, float alpha) {
try {
File img = new File(srcImageFile);
Image src = ImageIO.read(img);
int wideth = src.getWidth(null);
int height = src.getHeight(null);
BufferedImage image = new BufferedImage(wideth, height,
BufferedImage.TYPE_INT_RGB);
Graphics2D g = image.createGraphics();
g.drawImage(src, 0, 0, wideth, height, null);
// 水印文件
Image src_biao = ImageIO.read(new File(pressImg));
int wideth_biao = src_biao.getWidth(null);
int height_biao = src_biao.getHeight(null);
g.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_ATOP,
alpha));
g.drawImage(src_biao, (wideth - wideth_biao) / 2,
(height - height_biao) / 2, wideth_biao, height_biao, null);
// 水印文件结束
g.dispose();
ImageIO.write((BufferedImage) image, "JPEG", new File(destImageFile));
} catch (Exception e) {
e.printStackTrace();
}
} /**
* 计算text的长度（一个中文算两个字符）
*
* @param text
* @return
*/
public final static int getLength(String text) {
int length = 0;
for (int i = 0; i < text.length(); i++) {
if (new String(text.charAt(i) + "").getBytes().length > 1) {
length += 2;
} else {
length += 1;
}
}
return length / 2;
}
}
注：如果在JQ中ajax方法没有执行，请检查Json返回的数据格式是否正确！