1.前端上传图片JS压缩
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<%
String contextPath = request.getContextPath();
%>
<!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">
<meta name="viewport" content="initial-scale=1,maximum-scale=1,user-scalable=no,width=device-width,height=device-height">
<script src="<%=contextPath%>/js/jquery-1.11.3.js"></script>
<title>图片上传</title>
<style type="text/css">
.float_zm{
float_zm:left;
width : 200px;
height: 200px;
overflow: hidden;
border: 1px solid #CCCCCC;
border-radius: 10px;
padding: 5px;
margin: 5px;
position:absolute;
left:50%;
margin-left: -100px;
}
.result{
width: 200px;
height: 200px;
text-align: center;
box-sizing: border-box;
}
</style>
<script type="text/javascript">
$(function(){
var input = document.getElementById("file_input_zm");
if(typeof FileReader==='undefined'){
alert("抱歉，你的浏览器不支持 FileReader");
input.setAttribute('disabled','disabled');
}else{
input.addEventListener('change',readFile,false);
}
function readFile(){
var iLen = this.files.length;
var index = 0;
for(var i=0;i<iLen;i++){
if (!input['value'].match(/.jpg|.gif|.png|.jpeg|.bmp/i)){ //判断上传文件格式
return alert("上传的图片格式不正确，请重新选择");
}
/* if (this.files[i].size > 1048576){
return alert("上传的图片大小超过1M，请重新选择"); //判断上传图片大小
} */
var reader = new FileReader();
reader.index = i;
reader.readAsDataURL(this.files[i]); //转成base64
reader.fileName = this.files[i].name;
$("#sfzzm_name").val(reader.fileName);
reader.onload = function(e){
$("#zmtp").empty();
var result = '<div class="float_zm"><div onclick="select_zm()" class="result"><img id="sfzzm" src="'+this.result+'" /></div></div>';
$("#zmtp").html(result);
var img = document.getElementById('sfzzm');
img.onload = function(){
var nowHeight = ReSizePic(this); //设置图片预览大小
this.parentNode.style.display = 'block';
var oParent = this.parentNode;
if(nowHeight){
oParent.style.paddingTop = (oParent.offsetHeight - nowHeight)/2 + 'px';
}
//压缩照片
var base64 = yszp(img,this);
$("#sfzzm_base64").val(base64);
}
}
}
}
})
//压缩照片
function yszp(img,ThisPic){
//缩放图片需要的canvas
var canvas = document.createElement('canvas');
var context = canvas.getContext('2d');
// 图片原始尺寸
var originWidth = ThisPic.width;
var originHeight = ThisPic.height;
// 最大尺寸限制
var maxWidth = 200, maxHeight = 200;
// 目标尺寸
var targetWidth = originWidth, targetHeight = originHeight;
// 图片尺寸超过200x200的限制
if (originWidth > maxWidth || originHeight > maxHeight) {
if (originWidth / originHeight > maxWidth / maxHeight) {
// 更宽，按照宽度限定尺寸
targetWidth = maxWidth;
targetHeight = Math.round(maxWidth * (originHeight / originWidth));
} else {
targetHeight = maxHeight;
targetWidth = Math.round(maxHeight * (originWidth / originHeight));
}
}
// canvas对图片进行缩放
canvas.width = targetWidth;
canvas.height = targetHeight;
// 清除画布
context.clearRect(0, 0, targetWidth, targetHeight);
// 图片压缩
context.drawImage(img, 0, 0, targetWidth, targetHeight);
// 返回压缩后的base64
return canvas.toDataURL();
}
function ReSizePic(ThisPic) {
var RePicWidth = 200; //目标宽度
var TrueWidth = ThisPic.width; //图片实际宽度
var TrueHeight = ThisPic.height; //图片实际高度
if(TrueWidth>TrueHeight){
//宽大于高
var reWidth = RePicWidth;
ThisPic.width = reWidth;
//垂直居中
var nowHeight = TrueHeight * (reWidth/TrueWidth);
return nowHeight; //将图片修改后的高度返回，供垂直居中用
}else{
//宽小于高
var reHeight = RePicWidth;
ThisPic.height = reHeight;
}
}
//选择照片
function select_zm(){
$("#file_input_zm").click();
}
//上传
function myCheck(){
var sfzzm = $("#sfzzm").attr("src");
if(sfzzm == ''){
alert("请选择照片");
return false;
}
$("#form").submit();
}
</script>
</head>
<body>
<form id="form" action="wap_ajbj_upload_save.htm" method="post" enctype="multipart/form-data">
<input type="hidden" id="sfzzm_name" name="sfzzm_name">
<input type="hidden" id="sfzzm_base64" name="sfzzm_base64">
<input type="file" id="file_input_zm" name="file_input_zm" style="display: none;"/>
<div id="zmtp" style="width: 100%;height: 240px;position:relative;">
<div class="float_zm">
<div class="result" onclick="select_zm()">
<img id="sfzzm" name="sfzzm" />
<span id="zpbz" style="font-size: 16px;line-height: 200px;">照片(点击上传)</span>
</div>
</div>
</div>
<div style="text-align: center;margin: 0 auto;">
<button style="width: 80%;" type="button" onclick="myCheck()">上传</button>
</div>
</form>
</body>
</html>2.后端保存图片
@RequestMapping(value = "wap_ajbj_upload_save.htm", method = { RequestMethod.GET,RequestMethod.POST })
public ModelAndView wap_ajbj_upload_save(MultipartHttpServletRequest request) throws Exception {
ModelAndView mv = new ModelAndView("wap/ajbj_index");
String sfzzm_base64 = request.getParameter("sfzzm_base64");
String sfzzm_name = request.getParameter("sfzzm_name");
String suffix = sfzzm_name.substring(sfzzm_name.lastIndexOf(".") + 1);
String filename = System.currentTimeMillis() + "." + suffix;
String path = filePath + "/ajbj/zm/"+filename;
sfzzm_base64 = sfzzm_base64.split(",")[1];
GenerateImage(sfzzm_base64, path);
return mv;
}
/**
* @Description: 将base64编码字符串转换为图片
* @param imgStr base64编码字符串
* @param path 图片路径-具体到文件
*/
public static boolean GenerateImage(String imgStr,String imgFilePath){
if (imgStr == null) //图像数据为空
return false;
BASE64Decoder decoder = new BASE64Decoder();
try{
//Base64解码
byte[] b = decoder.decodeBuffer(imgStr);
for(int i=0;i<b.length;++i){
if(b[i] < 0){//调整异常数据
b[i] += 256;
}
}
OutputStream out = new FileOutputStream(imgFilePath);
out.write(b);
out.flush();
out.close();
return true;
}
catch (Exception e){
return false;
}
}