因为项目当中用到图片裁剪，本来可以不用到后台进行裁剪的，但是要兼容万恶的IE浏览器，所以不得不使用后台进行裁剪。
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这次使用到imgareaselect 插件获取需要裁剪区域的坐标，再由后台进行裁剪操作。
但是这里有一个坑就是上传的图片过大，可能会造成裁剪的区域跟插件中显示的不一样，所以得现在后台对云图片进行压缩在裁剪。
/**
* 等比例压缩算法：
* 算法思想：根据压缩基数和压缩比来压缩原图，生产一张图片效果最接近原图的缩略图
* @param srcURL 原图地址
* @param deskURL 缩略图地址
* @param comBase 压缩基数
* @param scale 压缩限制(宽/高)比例 一般用1：
* 当scale>=1,缩略图height=comBase,width按原图宽高比例;若scale<1,缩略图width=comBase,height按原图宽高比例
* @throws Exception
*/
public static void saveMinPhoto(String srcURL, String deskURL, double comBase,
double scale) throws Exception {
File srcFile = new java.io.File(srcURL);
String ext = srcURL.substring(srcURL.lastIndexOf(".") + 1);
Image src = ImageIO.read(srcFile);
int srcHeight = src.getHeight(null);
int srcWidth = src.getWidth(null);
int deskHeight = 0;// 缩略图高
int deskWidth = 0;// 缩略图宽
double srcScale = (double) srcHeight / srcWidth;
/**缩略图宽高算法*/
if ((double) srcHeight > comBase || (double) srcWidth > comBase) {
if (srcScale >= scale || 1 / srcScale > scale) {
if (srcScale >= scale) {
deskHeight = (int) comBase;
deskWidth = srcWidth * deskHeight / srcHeight;
} else {
deskWidth = (int) comBase;
deskHeight = srcHeight * deskWidth / srcWidth;
}
} else {
if ((double) srcHeight > comBase) {
deskHeight = (int) comBase;
deskWidth = srcWidth * deskHeight / srcHeight;
} else {
deskWidth = (int) comBase;
deskHeight = srcHeight * deskWidth / srcWidth;
}
}
} else {
deskHeight = srcHeight;
deskWidth = srcWidth;
}
BufferedImage tag = new BufferedImage(deskWidth, deskHeight, BufferedImage.TYPE_3BYTE_BGR);
tag.getGraphics().drawImage(src, 0, 0, deskWidth, deskHeight, null); //绘制缩小后的图
FileOutputStream deskImage = new FileOutputStream(deskURL); //输出到文件流
ImageIO.write(tag, ext, new File(deskURL));
deskImage.close();
}
这就是压缩之后在进行裁剪了，好了上完整代码先
js 代码
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)
});
$('#x1').val(selection.x1);
$('#y1').val(selection.y1);
$('#x2').val(selection.x2);
$('#y2').val(selection.y2);
$('#w').val(selection.width);
$('#h').val(selection.height);
}
$(function () {
});
//上传原始图片
function uplodImage(target) {
if(checkImage(target)){
var url = httpUtils.rootPath+'/component/upload.do';
$.ajaxFileUpload({
url: url, //用于文件上传的服务器端请求地址
secureuri: false, //是否需要安全协议，一般设置为false
fileElementId: 'uplodimage', //文件上传域的ID
dataType: 'json', //返回值类型 一般设置为json
success: function (data) //服务器成功响应处理函数
{
var filePath = data.filePath;
$('#photo').attr('src',httpUtils.rootPath+'/component/upload.do?action=download&filepath='+filePath);
$('#smallImage').attr('src',httpUtils.rootPath+'/component/upload.do?action=download&filepath='+filePath);
$('#imgUrl').val(filePath);
$('#photo').imgAreaSelect({
aspectRatio: '1:1',
x1: 50, y1: 50, x2: 241, y2: 241,
handles: true,
fadeSpeed: 200,
onSelectChange: preview
});
$('#x1').val("50");
$('#y1').val("50");
$('#x2').val("241");
$('#y2').val("241");
$('#w').val("191");
$('#h').val("191");
}
});
}
}
//上传裁剪后的图片
function upold() {
if($('#imgUrl').val()==''){
layer.alert("请先选择图片在上传");
return false;
}
$.ajax({
type: "post",
url:httpUtils.rootPath+'/user/setHeadPicture',
beforeSend: function(request) {
request.setRequestHeader("jmtcp", header);
},
async:false,
data: {
x:$('#x1').val(),
y:$('#y1').val(),
width: $('#w').val(),
imgUrl : $('#imgUrl').val(),
heigth: $('#h').val()
},
dataType: "json",
success: function(data){
if(data.code==1){
layer.alert(data.message,function(){
window.location.href = '../user/grzy.html';
});
}else{
layer.alert(data.message);
}
}
});
}
function checkImage(target) {
var isIE = /msie/i.test(navigator.userAgent) && !window.opera;
var fileSize = 0;
var filepath = target.value;
// 为了避免转义反斜杠出问题，这里将对其进行转换
var re = /(\+)/g;
var filename = filepath.replace(re, "#");
// 对路径字符串进行剪切截取
var one = filename.split("#");
// 获取数组中最后一个，即文件名
var two = one[one.length - 1];
// 再对文件名进行截取，以取得后缀名
var three = two.split(".");
// 获取截取的最后一个字符串，即为后缀名
var last = three[three.length - 1];
// 添加需要判断的后缀名类型
var tp = "jpg,gif,bmp,JPG,GIF,BMP,png";
// 返回符合条件的后缀名在字符串中的位置
var rs = tp.indexOf(last);
// 如果返回的结果大于或等于0，说明包含允许上传的文件类型
if(rs < 0){
layer.alert('您选择的上传文件不是有效的图片文件');
return false;
}
// if (isIE && !target.files) { // IE浏览器
// var filePath = target.value; // 获得上传文件的绝对路径
// var fileSystem = new ActiveXObject("Scripting.FileSystemObject");
// // GetFile(path) 方法从磁盘获取一个文件并返回。
// var file = fileSystem.GetFile(filePath);
// fileSize = file.Size; // 文件大小，单位：b
// }
// else { // 非IE浏览器
// fileSize = target.files[0].size;
// }
var img1 = document.getElementById('photo');
//img1.dynsrc=target.value;
//img1.fileSize：IE ， fileObj.files[0].fileSize：chrome， fileObj.files[0].size：FF
var fileSize = img1.fileSize || target.files[0].fileSize || target.files[0].size;
var size = fileSize / 1024 / 1024;
if (size > 5) {
layer.alert("图片不能大于5M");
return false;
}
return true;
}
后台代码
public class CutImageUtils {
public static SecureRandom rnd = new SecureRandom();
public static String cutImage(int x, int y, int width, int height,String srcPath) throws Exception{
String root = ApplicationContext.getProperty("upload_folder");
String imagePath = root+srcPath;
FileInputStream is = null;
ImageInputStream iis = null;
String uploadFolder = null ;
String filepath = null ;
String serverName = null ;
uploadFolder = ApplicationContext.getProperties().getProperty("upload_folder").toString() ;
filepath = generateServerFolder() ;
serverName = generateServerName(srcPath) ;
File file = new File(uploadFolder + filepath);
if (!file.exists()) {
file.mkdirs();
}
try {
// 读取图片文件
saveMinPhoto(imagePath, imagePath, 300, 0.9d);
//resetsize(imagePath, imagePath);
is = new FileInputStream(imagePath);
String ext = srcPath.substring(srcPath.lastIndexOf(".") + 1);
Iterator it = ImageIO.getImageReadersByFormatName(ext);
ImageReader reader = it.next();
// 获取图片流
iis = ImageIO.createImageInputStream(is);
reader.setInput(iis, true);
ImageReadParam param = reader.getDefaultReadParam();
/**
*
* 图片裁剪区域。Rectangle 指定了坐标空间中的一个区域，通过 Rectangle 对象
*
* 的左上顶点的坐标(x，y)、宽度和高度可以定义这个区域。
*/
Rectangle rect = new Rectangle(x, y, width, height);
// 提供一个 BufferedImage，将其用作解码像素数据的目标。
param.setSourceRegion(rect);
BufferedImage bi = reader.read(0, param);
// 保存新图片
ImageIO.write(bi, ext, new File(uploadFolder + filepath + serverName));
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
if (is != null)
is.close();
if (iis != null)
iis.close();
e.printStackTrace();
}
return filepath + serverName ;
}
/**
*
* @param config
* @param file
* @param request
* @return
*/
public static String generateServerName(String clientPath) {
//按当前时间的分钟毫秒+3位随机数
Calendar c = Calendar.getInstance();
String min = get(c,Calendar.MINUTE);
String sec = get(c,Calendar.SECOND);
String mis = get(c,Calendar.MILLISECOND);
String rnd = random();
String ext = getFileExt(getClientName(clientPath));
return min + sec + mis + rnd + ext ;
}
/** 客户端文件名 */
public static String getClientName(String clientPath) {
if(null != clientPath){
int index1 = clientPath.lastIndexOf("/");
int index2 = clientPath.lastIndexOf("\\");
if(index2 > index1){
index1 = index2;
}
return clientPath.substring(index1+1,clientPath.length());
}
return null;
}
public static String getFileExt(String fileName){
if(null != fileName){
int dot = fileName.lastIndexOf(".");
if(dot >= 0){
return fileName.substring(dot);
}
}
return "";
}
public static String random(){
String value = String.valueOf(rnd.nextInt(1000));
if(value.length() < 3){
for(int i=value.length();i<3;i++){
value = "0" + value;
}
}
return value;
}
public static String generateServerFolder() {
//按当前年月日和小时生成文件路径
Calendar c = Calendar.getInstance();
String year = get(c,Calendar.YEAR);
String mon = get(c,Calendar.MONTH);
String day = get(c,Calendar.DAY_OF_MONTH);
String hour = get(c,Calendar.HOUR_OF_DAY);
return year + "/" + mon + "/" + day + "/" + hour + "/";
}
public static String get(Calendar c,int field){
int v = c.get(field);
if(field == Calendar.MONTH){
v += 1;
}
String value = String.valueOf(v);
if(value.length() == 1){
value = "0" + value;
}
return value;
}
/**
* 缩小图片到固定长高
* @param srcImagePath 读取图片路径
* @param toImagePath 写入图片路径
* @param width 缩小后图片宽度
* @param height 缩小后图片长度
* @throws IOException
*/
public static void reduceImageByWidthHeight(String srcImagePath, String toImagePath, int width, int height) throws IOException{
FileOutputStream out = null;
try{
//读入文件
File file = new File(srcImagePath);
String ext = srcImagePath.substring(srcImagePath.lastIndexOf(".") + 1);
// 构造Image对象
BufferedImage src = javax.imageio.ImageIO.read(file);
// 缩小边长
BufferedImage tag = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
// 绘制缩小后的图片
tag.getGraphics().drawImage(src, 0, 0, width, height, null);
out = new FileOutputStream(toImagePath);
ImageIO.write(tag, ext, new File(toImagePath));
}catch(Exception e){
e.printStackTrace();
}finally{
if(out != null){
out.close();
}
out = null;
System.gc();
}
}
/**
* 等比例压缩算法：
* 算法思想：根据压缩基数和压缩比来压缩原图，生产一张图片效果最接近原图的缩略图
* @param srcURL 原图地址
* @param deskURL 缩略图地址
* @param comBase 压缩基数
* @param scale 压缩限制(宽/高)比例 一般用1：
* 当scale>=1,缩略图height=comBase,width按原图宽高比例;若scale<1,缩略图width=comBase,height按原图宽高比例
* @throws Exception
*/
public static void saveMinPhoto(String srcURL, String deskURL, double comBase,
double scale) throws Exception {
File srcFile = new java.io.File(srcURL);
String ext = srcURL.substring(srcURL.lastIndexOf(".") + 1);
Image src = ImageIO.read(srcFile);
int srcHeight = src.getHeight(null);
int srcWidth = src.getWidth(null);
int deskHeight = 0;// 缩略图高
int deskWidth = 0;// 缩略图宽
double srcScale = (double) srcHeight / srcWidth;
/**缩略图宽高算法*/
if ((double) srcHeight > comBase || (double) srcWidth > comBase) {
if (srcScale >= scale || 1 / srcScale > scale) {
if (srcScale >= scale) {
deskHeight = (int) comBase;
deskWidth = srcWidth * deskHeight / srcHeight;
} else {
deskWidth = (int) comBase;
deskHeight = srcHeight * deskWidth / srcWidth;
}
} else {
if ((double) srcHeight > comBase) {
deskHeight = (int) comBase;
deskWidth = srcWidth * deskHeight / srcHeight;
} else {
deskWidth = (int) comBase;
deskHeight = srcHeight * deskWidth / srcWidth;
}
}
} else {
deskHeight = srcHeight;
deskWidth = srcWidth;
}
BufferedImage tag = new BufferedImage(deskWidth, deskHeight, BufferedImage.TYPE_3BYTE_BGR);
tag.getGraphics().drawImage(src, 0, 0, deskWidth, deskHeight, null); //绘制缩小后的图
FileOutputStream deskImage = new FileOutputStream(deskURL); //输出到文件流
ImageIO.write(tag, ext, new File(deskURL));
deskImage.close();
}
public static void main(String[] args) {
try {
String src = CutImageUtils.cutImage(11, 12, 100, 100, "2017/01/04/17/6348162d-5b50-4e7d-b414-93140498f8de.jpg");
System.out.println(src);
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持创新互联。
新闻标题：利用imgareaselect辅助后台实现图片上传裁剪
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