当采用post方式向服务器发送请求时，并且表单中被输入了中文时，往往会出现乱码的状况。
request.setCharacterEncoding("UTF-8");对于利用Ajax发送post请求，浏览器统一使用UTF-8进行编码。此行代码的作用就是以编程的方式指定让Tomcat服务器以UTF-8进行解码，这样编码和解码就保持了一致。
测试代码如下：
register.jsp :
<%@ page contentType="text/html;charset=UTF-8" pageEncoding="UTF-8"%>
<html>
<head>
<title>Insert title here</title>
<script type="text/javascript" src="js/prototype1.6.js"></script>
<script type="text/javascript">
function getXmlHttpRequest(){
var xhr=null;
if((typeof XMLHttpRequest)!='undefined'){
xhr=new XMLHttpRequest();
}else{
xhr=new ActiveXObject("Microsoft.XMLHttp");
}
return xhr;
}
function valiUsername(){
var xhr=getXmlHttpRequest();
xhr.onreadystatechange=function(){
if(xhr.readyState==4){
if(xhr.status==200){
var doc=xhr.responseText;
document.getElementById('username_msg').innerHTML=doc;
}else{
document.getElementById('username_msg').innerHTML="系统错误...";
}
}else{
document.getElementById('username_msg').innerHTML="验证中...";
}
}
var url="valiusername.do";
xhr.open("post",url,true);
xhr.setRequestHeader("Content-Type","application/x-www-form-urlencoded");
xhr.send("username="+document.getElementById('n1').value);
}
</script>
</head>
<body>
<form action="register.do" method="post">
姓名:<input type="text" name="username" id="n1" onblur="valiUsername();">
<span style="color:red" id="username_msg"></span><br>
密码:<input type="password" name="password"><br>
<input type="submit" value="注册">
</form>
</body>
</html>
UsernameServlet.java :
public class UsernameServlet extends HttpServlet {
public void service(HttpServletRequest request,HttpServletResponse response)
throws ServletException,IOException {
request.setCharacterEncoding("UTF-8");
String uri=request.getRequestURI();
String path=uri.substring(uri.lastIndexOf("/"),uri.lastIndexOf("."));
response.setContentType("text/html;charset=UTF-8");
PrintWriter pw=response.getWriter();
if(path.equals("/valiusername")){
String username=request.getParameter("username");
System.out.println("姓名:"+username);
if(username.equals("格林")){
pw.println("用户名已经占用");
}else{
pw.println("用户名可以使用");
}
}
if(path.equals("/register")){
String username=request.getParameter("username");
String password=request.getParameter("password");
response.sendRedirect("login.jsp");
}
}
}
原文链接：https://www.f2er.com/ajax/166224.html