java怎么读取指定url的图片

你使用URL.openStream,将内容输入到一个文件里，发现其实这不是一张图片，而是一张HTML页面。内部是一段加密的js.
解密后，发现这端js的执行如下逻辑:

var dynamicurl = "http://shixin.court.gov.cn/image.jsp";
var wzwschallenge = "RANDOMSTR11904";
var wzwschallengex = "STRRANDOM11904";
var template = 10;
var encoderchars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
function KTKY2RBD9NHPBCIHV9ZMEQQDARSLVFDU(str) {
var out, i, len;
var c1, c2, c3;
len = str.length;
i = 0;
out = "";
while (i < len) {
c1 = str.charCodeAt(i++) & 0xff;
if (i == len) {
out += encoderchars.charAt(c1 >> 2);
out += encoderchars.charAt((c1 & 0x3) << 4);
out += "==";
break;
}
c2 = str.charCodeAt(i++);
if (i == len) {
out += encoderchars.charAt(c1 >> 2);
out += encoderchars.charAt(((c1 & 0x3) << 4) | ((c2 & 0xf0) >> 4));
out += encoderchars.charAt((c2 & 0xf) << 2);
out += "=";
break;
}
c3 = str.charCodeAt(i++);
out += encoderchars.charAt(c1 >> 2);
out += encoderchars.charAt(((c1 & 0x3) << 4) | ((c2 & 0xf0) >> 4));
out += encoderchars.charAt(((c2 & 0xf) << 2) | ((c3 & 0xc0) >> 6));
out += encoderchars.charAt(c3 & 0x3f);
}
return out;
}
function findDimensions() {
var w = window.innerWidth || document.documentElement.clientWidth || document.body.clientWidth;
var h = window.innerHeight || document.documentElement.clientHeight || document.body.clientHeight;
if (w * h <= 120000) {
return true;
}
var x = window.screenX;
var y = window.screenY;
if (x + w <= 0 || y + h <= 0 || x >= window.screen.width || y >= window.screen.height) {
return true;
}
return false;
}
function QWERTASDFGXYSF() {
var tmp = wzwschallenge + wzwschallengex;
var hash = 0;
var i = 0;
for (i = 0; i < tmp.length; i++) {
hash += tmp.charCodeAt(i);
}
hash *= 31;
hash += 111111;
return "WZWS_CONFIRM_PREFIX_LABEL10" + hash;
}
function HXXTTKKLLPPP5() {
if (findDimensions()) {} else {
var cookieString = "";
cookieString = "wzwstemplate=" + KTKY2RBD9NHPBCIHV9ZMEQQDARSLVFDU(template.toString()) + "; path=/";
document.cookie = cookieString;
var confirm = QWERTASDFGXYSF();
cookieString = "wzwschallenge=" + KTKY2RBD9NHPBCIHV9ZMEQQDARSLVFDU(confirm.toString()) + "; path=/";
document.cookie = cookieString;
window.location = dynamicurl;
}
}
HXXTTKKLLPPP5();

//粗略看下，逻辑应该是：
服务端拿cookie信息，判断是不是一笔正常的请求，如果是，下发图片，如果不是下面之前拉下来的页面，重新初始化cookie.