头像上传裁剪预览功能-java

1.实现说明

原文是开源中国上的一个demo，文章最后给出原文链接，上面有源码。实现框架是：maven+springmvc+jcrop。需要的主要js和css文件为jquery.Jcrop.css，jquery.min.js，jquery.Jcrop.js。

2.一言不合上代码

2.1 controller层

import java.io.File;import javax.servlet.http.HttpServletRequest;import org.springframework.stereotype.Controller;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RequestMethod;import org.springframework.web.bind.annotation.RequestParam;import org.springframework.web.multipart.MultipartFile;@Controller @RequestMapping("/UploadDemo")public class UploadImgController {    @RequestMapping(value = "/uploadHeadImage",method = RequestMethod.POST)    public String uploadHeadImage(            HttpServletRequest request,            @RequestParam(value = "x") String x,            @RequestParam(value = "y") String y,            @RequestParam(value = "h") String h,            @RequestParam(value = "w") String w,            @RequestParam(value = "imgFile") MultipartFile imageFile    ) throws Exception{        System.out.println("==========Start=============");        String realPath = request.getSession().getServletContext().getRealPath("/");        String resourcePath = "resources/uploadImages/";        if(imageFile!=null){            if(FileUploadUtil.allowUpload(imageFile.getContentType())){                String fileName = FileUploadUtil.rename(imageFile.getOriginalFilename());                int end = fileName.lastIndexOf(".");                String saveName = fileName.substring(0,end);                File dir = new File(realPath + resourcePath);                if(!dir.exists()){                    dir.mkdirs();                }                File file = new File(dir,saveName+"_src.jpg");                imageFile.transferTo(file);                String srcImagePath = realPath + resourcePath + saveName;                int imageX = Integer.parseInt(x);                int imageY = Integer.parseInt(y);                int imageH = Integer.parseInt(h);                int imageW = Integer.parseInt(w);                //这里开始截取操作                System.out.println("==========imageCutStart=============");                ImgCut.imgCut(srcImagePath,imageX,imageY,imageW,imageH);                System.out.println("==========imageCutEnd=============");                request.getSession().setAttribute("imgSrc",resourcePath + saveName+"_src.jpg");//成功之后显示用                request.getSession().setAttribute("imgCut",resourcePath + saveName+"_cut.jpg");//成功之后显示用            }        }        return "success";    }}

2.2 两个工具类

文件上传工具类：

import java.util.Arrays;import java.util.Date;import java.util.List;import java.util.Random;public class FileUploadUtil {     public static final List<String> ALLOW_TYPES = Arrays.asList(                "image/jpg","image/jpeg","image/png","image/gif"        );    //文件重命名        public static String rename(String fileName){            int i = fileName.lastIndexOf(".");            String str = fileName.substring(i);            return new Date().getTime()+""+ new Random().nextInt(99999999) +str;        }    //校验文件类型是否是被允许的        public static boolean allowUpload(String postfix){            return ALLOW_TYPES.contains(postfix);        }}

图片裁剪工具类：
import java.awt.Graphics;
import java.awt.Image;
import java.awt.Toolkit;
import java.awt.image.BufferedImage;
import java.awt.image.CropImageFilter;
import java.awt.image.FilteredImageSource;
import java.awt.image.ImageFilter;
import java.io.File;

import javax.imageio.ImageIO;

public class ImgCut {
/**
* 截取图片
* @param srcImageFile 原图片地址
* @param x 截取时的x坐标
* @param y 截取时的y坐标
* @param desWidth 截取的宽度
* @param desHeight 截取的高度
*/
public static void imgCut(String srcImageFile, int x, int y, int desWidth,
int desHeight) {
try {
Image img;
ImageFilter cropFilter;
BufferedImage bi = ImageIO.read(new File(srcImageFile+”_src.jpg”));
int srcWidth = bi.getWidth();
int srcHeight = bi.getHeight();
if (srcWidth >= desWidth && srcHeight >= desHeight) {
Image image = bi.getScaledInstance(srcWidth, srcHeight,Image.SCALE_DEFAULT);
cropFilter = new CropImageFilter(x, y, desWidth, desHeight);
img = Toolkit.getDefaultToolkit().createImage(
new FilteredImageSource(image.getSource(), cropFilter));
BufferedImage tag = new BufferedImage(desWidth, desHeight,
BufferedImage.TYPE_INT_RGB);
Graphics g = tag.getGraphics();
g.drawImage(img, 0, 0, null);
g.dispose();
//输出文件
ImageIO.write(tag, “JPEG”, new File(srcImageFile+”_cut.jpg”));
}
} catch (Exception e) {
e.printStackTrace();
}
}
}

2.3 Jsp页面

index.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"    pageEncoding="UTF-8"%><%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>demo</title><link rel="stylesheet" href="<c:url value="/resources/jcrop/css/jquery.Jcrop.css"/>" type="text/css"></link><script type="text/javascript" src="<c:url value="/resources/jcrop/js/jquery.min.js"/>"></script><script type="text/javascript" src="<c:url value="/resources/jcrop/js/jquery.Jcrop.js"/>"></script></head><body>    <form name="form" action="<%=request.getContextPath()%>/UploadDemo/uploadHeadImage" class="form-horizontal" method="post" enctype="multipart/form-data">        <div class="modal-body text-center">            <div class="zxx_main_con">                <div class="zxx_test_list">                    <input class="photo-file" type="file" name="imgFile" id="fcupload" onchange="readURL(this);" />                    <img alt="" src="" id="cutimg" />                     <input type="hidden" id="x" name="x" />                     <input type="hidden" id="y" name="y" />                     <input type="hidden" id="w" name="w" />                     <input type="hidden" id="h" name="h" />                </div>            </div>        </div>        <div id="preview-pane">            <div class="preview-container">                <img src="" class="jcrop-preview" alt="预览">            </div>        </div>        <div class="modal-footer">            <button id="submit" onclick="">上传</button>        </div>    </form>    <script type="text/javascript">        //定义一个全局api，这样操作起来比较灵活        var api = null,         boundx,         boundy,         $preview = $('#preview-pane'),         $pcnt = $('#preview-pane .preview-container'),         $pimg = $('#preview-pane .preview-container img'),        xsize = $pcnt.width(),         ysize = $pcnt.height();        function readURL(input) {            if (input.files && input.files[0]) {                var reader = new FileReader();                reader.readAsDataURL(input.files[0]);                reader.onload = function(e) {                    $('#cutimg').removeAttr('src');                    $('#cutimg').attr('src', e.target.result);                    $pimg.removeAttr('src');                    $pimg.attr('src', e.target.result);                    api = $.Jcrop('#cutimg', {                        setSelect: [ 20, 20, 200, 200 ],                        aspectRatio: 1,                        onSelect: updateCoords,                        onChange:updateCoords                    });                    var bounds = api.getBounds();                    boundx = bounds[0];                    boundy = bounds[1];                    $preview.appendTo(api.ui.holder);                };                if (api != undefined) {                    api.destroy();                }            }            function updateCoords(obj) {                $("#x").val(obj.x);                $("#y").val(obj.y);                $("#w").val(obj.w);                $("#h").val(obj.h);                if (parseInt(obj.w) > 0) {                    var rx = xsize / obj.w;                    var ry = ysize / obj.h;                    $pimg.css({                        width : Math.round(rx * boundx) + 'px',                        height : Math.round(ry * boundy) + 'px',                        marginLeft : '-' + Math.round(rx * obj.x) + 'px',                        marginTop : '-' + Math.round(ry * obj.y) + 'px'                    });                }            }            ;        }    </script></body></html>

原文链接：http://my.oschina.net/zhengweishan/blog/700677。