Ajax快速入门
- 编写AjaxServlet,并使用response输出字符串
- 创建XMLHttpRequest对象:用于和服务器交换数据
- 向服务器发送请求
- 获取服务器响应数据
//AjaxServlet.java
@WebServlet("/ajaxServlet")
public class AjaxServlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// 1. 响应数据
response.getWriter().write("hello ajax~");
}
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doGet(request, response);
}
}
<!--客户端代码-->
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
</head>
<body>
<script>
// 1. 创建核心对象
var xhttp;
if (window.XMLHttpRequest) {
xhttp = new XMLHttpRequest();
} else {
// code for IE6, IE5
xhttp = new ActiveXObject("Microsoft.XMLHTTP");
}
// 2. 向服务器发送请求
xhttp.open("GET", "http://localhost:8080/ajax-demo/ajaxServlet", true);
xhttp.send();
// 3. 获取服务器的响应数据
xhttp.onreadystatechange = function() {
if (this.readyState == 4 && this.status == 200) {
alert(this.responseText);
}
};
</script>
</body>
</html>