2.3 步骤
步骤一： 新建ajax02.html页面
步骤二： 添加getText()方法，并补充超链接对该方法的调用
<html>
<head>
<title>ajax02.html</title>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<script type="text/javascript">
function getXhr(){
var xhr = null;
if(window.XMLHttpRequest){
xhr = new XMLHttpRequest();
}else{
xhr = new ActiveXObject("Microsoft.XMLHttp");
}
return xhr;
}
function getText(){
//1.获取Ajax对象
var xhr = getXhr();
//2.设置回调函数
xhr.onreadystatechange=function(){
if(xhr.readyState==4 && xhr.status==200){
var txt = xhr.responseText;
alert(txt);
}
};
//3.创建请求
xhr.open("get","get_text.do",true);
//4.发送请求
xhr.send(null);
}
</script>
</head>
<body>
<!-- 获取服务器端一小段文本 -->
<a href="javascript:;" onclick="getText()">获取文本</a>
</body>
</html>
步骤三： 编写ActionServlet类
package web;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class ActionServlet extends HttpServlet {
public void service(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html;charset=UTF-8");
PrintWriter out = response.getWriter();
//获取请求资源路径
String uri = request.getRequestURI();
String path = uri.substring(
uri.lastIndexOf("/"),
uri.lastIndexOf("."));
if(path.equals("/get_text")){//get请求
out.println("get请求-服务器返回的数据");
}
out.close();
}
}
步骤四： 部署、运行，查看结果
点击链接：
2.4 完整代码
ajax02.html页面代码：
<html>
<head>
<title>ajax02.html</title>
<meta http-equiv="Content-Type"
content="text/html; charset=UTF-8">
<script type="text/javascript">
function getXhr(){
var xhr = null;
if(window.XMLHttpRequest){
xhr = new XMLHttpRequest();
}else{
xhr = new ActiveXObject("Microsoft.XMLHttp");
}
return xhr;
}
function getText(){
//1.获取Ajax对象
var xhr = getXhr();
//2.设置回调函数
xhr.onreadystatechange=function(){
if(xhr.readyState==4 && xhr.status==200){
var txt = xhr.responseText;
alert(txt);
}
};
//3.创建请求
xhr.open("get","get_text.do",true);
//4.发送请求
xhr.send(null);
}
</script>
</head>
<body>
<!-- 获取服务器端一小段文本 -->
<a href="javascript:;" onclick="getText()">获取文本</a>
</body>
</html>
