jQuery+Jcrop 实现图片裁剪预览功能

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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>