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);

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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。