Java实现图片裁剪预览功能
在项目中，我们需要做些类似头像上传，图片裁剪的功能，ok看下面文章！
需要插件：jQuery Jcrop
后端代码：
package org.csg.upload; import java.awt.Rectangle; import java.awt.image.BufferedImage; import java.io.File; import java.io.FileInputStream; import java.io.IOException; import java.util.Iterator; import javax.imageio.ImageIO; import javax.imageio.ImageReadParam; import javax.imageio.ImageReader; import javax.imageio.stream.ImageInputStream; public class Upload { /** * @author 小夜的传说 * @param path1 图片原路径 * @param path2 裁剪后存储的路径 * @param x x轴 * @param y y轴 * @param w * @param h */ public static void CutImage(String path1,String path2,int x,int y,int w,int h){ FileInputStream fileInputStream=null; ImageInputStream iis=null; try { //读取图片文件，建立文件输入流 fileInputStream=new FileInputStream(path1); //创建图片的文件流 迭代器 Iterator<ImageReader> it = ImageIO.getImageReadersByFormatName("jpg"); ImageReader reader=it.next(); //获取图片流 建立文图 文件流 iis=ImageIO.createImageInputStream(fileInputStream); //获取图片默认参数 reader.setInput(iis, true); ImageReadParam param=reader.getDefaultReadParam(); //定义裁剪区域 Rectangle rect=new Rectangle(x,y,w,h); param.setSourceRegion(rect); BufferedImage bi=reader.read(0,param); ImageIO.write(bi, "jpg", new File(path2)); } catch (Exception e) { e.printStackTrace(); System.out.println("裁剪失败"); }finally{ try { if(fileInputStream!=null){ fileInputStream.close(); } if(iis!=null){ iis.close(); } } catch (IOException e) { e.printStackTrace(); } } } } 访问代码：
<%@ page language="java" import="java.util.*,org.csg.upload.*" pageEncoding="utf-8"%> <% //图片的相对路径 String imagPath=request.getParameter("imgPath"); String relPath=request.getRealPath("/");//获取图片服务器绝对地址 String newFileName=new Date().getTime()+".jpg"; //实际图片路径 String path1=relPath+imagPath; //裁剪后存储到服务器的图片路径 String path2=relPath+"/images/"+newFileName; int x=Integer.parseInt(request.getParameter("x")); int y=Integer.parseInt(request.getParameter("y")); int w=Integer.parseInt(request.getParameter("w")); int h=Integer.parseInt(request.getParameter("h")); try{ Upload.CutImage(path1, path2, x, y, w, h); out.print("<img src='images/"+newFileName+"'/>"); }catch(Exception e){ e.printStackTrace(); out.print("图片裁剪失败"); } %> jsp代码：
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%> <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <title>Jsp开发头像裁剪</title> <meta http-equiv="pragma" content="no-cache"> <meta http-equiv="cache-control" content="no-cache"> <meta http-equiv="expires" content="0"> <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"> <meta http-equiv="description" content="This is my page"> <link rel="stylesheet" href="css/jquery.Jcrop.css" type="text/css" /> <script type="text/javascript" src="js/jquery.min.js"></script> <script type="text/javascript" src="js/jquery.Jcrop.min.js"></script> <style type="text/css"> *{margin: 0;padding: 0;} .cut{ margin-top: 20px; } #preview-pane { display: block; position: absolute; z-index: 2000; top: 10px; right: -280px; padding: 6px; border: 1px rgba(0,0,0,.4) solid; background-color: white; -webkit-border-radius: 6px; -moz-border-radius: 6px; border-radius: 6px; -webkit-box-shadow: 1px 1px 5px 2px rgba(0, 0, 0, 0.2); -moz-box-shadow: 1px 1px 5px 2px rgba(0, 0, 0, 0.2); box-shadow: 1px 1px 5px 2px rgba(0, 0, 0, 0.2); } #preview-pane .preview-container { width: 250px; height: 170px; overflow: hidden; } </style> <script type="text/javascript"> $(function(){ var jcrop_api, boundx="", boundy="", $preview = $('#preview-pane'), $pcnt = $('#preview-pane .preview-container'), $pimg = $('#preview-pane .preview-container img'), xsize = $pcnt.width(), ysize = $pcnt.height(); $('#cutImage').Jcrop({ onChange:showCoords,//获取选中的值 onSelect:showCoords,//获取拖拽的值 aspectRatio: xsize / ysize },function(){ var bounds = this.getBounds(); boundx = bounds[0]; boundy = bounds[1]; jcrop_api = this; $preview.appendTo(jcrop_api.ui.holder); }); function showCoords(c){ var x=c.x; var y=c.y; var w=c.w; var h=c.h; $("#x1").val(parseInt(x)); $("#y1").val(parseInt(y)); $("#w").val(parseInt(w)); $("#h").val(parseInt(h)); if (parseInt(c.w) > 0){ var rx = xsize / c.w; var ry = ysize / c.h; $pimg.css({ width: Math.round(rx * boundx) + 'px', height: Math.round(ry * boundy) + 'px', marginLeft: '-' + Math.round(rx * c.x) + 'px', marginTop: '-' + Math.round(ry * c.y) + 'px' }); } } }); </script> </head> <body> <h1>Java开发QQ头像裁剪系统</h1> <div class="cut"> <img id="cutImage" alt="" src="images/1.jpg" > <div id="preview-pane"> <div class="preview-container"> <img src="images/1.jpg" class="jcrop-preview" alt="Preview" /> </div> </div> </div> <form action="success.jsp" method="post" > <input type="text" value="images/1.jpg" name="imgPath"> x轴:<input type="text" size="4" id="x1" name="x" /> y轴:<input type="text" size="4" id="y1" name="y"/> 宽度:<input type="text" size="4" id="w" name="w"/> 高度:<input type="text" size="4" id="h" name="h"/> <input type="submit" value="裁剪"/> </form> </body> </html>