JSP XMLHttpRequest dynamic no refresh and its Chinese garble processing

1. On the page < script type="text/JavaScript" > To join in
// xmlhttp request with no refresh request
var http_request=false;
function createRequest(url)
{
http_request = false;
if (window.XMLHttpRequest) { // Mozilla, Safari,...
http_request = new XMLHttpRequest();
if (http_request.overrideMimeType) {
http_request.overrideMimeType('text/html');
}
} else if (window.ActiveXObject) { // IE
try {
http_request = new ActiveXObject("Msxml2.XMLHTTP");
} catch (e) {
try {
http_request = new ActiveXObject("Microsoft.XMLHTTP");
} catch (e) {}
}
}
if (!http_request) {
alert(' cannot create XMLHTTP instance! ');
return false;
}
http_request.onreadystatechange=alertContents;
http_request.open("POST",url,true);
http_request.send(null);
}
2. Call -- call request in js [CONTROL for servlet configuration of url-mapping, pass the same url 1 as url]
createRequest('CONTROL'+'?cmd=listen');
3. Dealing with [Chinese garble] in servlet
PrintWriter out;
response. setContentType (" html/text "); // this 5 lines must be used to output Chinese, otherwise garbled
response.setCharacterEncoding("UTF-8");
response.setHeader("Cache-Control","no-cache");
out=response.getWriter();
out.println(" sorry, the system is busy, please try again later!" ); // is the result of the response returned, displayed directly on the page as alert()