最简单的ajax示例

 

首先我们创建一个some.jsp如下(注意:不要将JSP文件放在子文件夹中,如果你这样做,请相应地更改servlet URL):

<!DOCTYPE html>

<html lang="en">

    <head>

        <title>TestAjax</title>

        <script src="http://code.jquery.com/jquery-latest.min.js"></script>

        <script>

            $(document).on("click", "#somebutton", function() {

                $.get("someservlet", function(responseText) {   

                    $("#somediv").text(responseText);         

                });

            });

        </script>

    </head>

    <body>

        <button id="somebutton">press here</button>

        <div id="somediv"></div>

    </body>

</html>

使用如下doGet()方法创建一个servlet 

@Override

protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

    String text = "some text";

    response.setContentType("text/plain");  // Set content type of the response so that jQuery knows what it can expect.

    response.setCharacterEncoding("UTF-8"); // You want world domination, huh?

    response.getWriter().write(text);       // Write response body.

}

将该servlet映射到URL模式/someservlet/someservlet/*下面(URL模式可以自由选择,但需要将someservlet所有位置相应地更改JS代码示例中的URL):

@WebServlet("/someservlet/*")

public class SomeServlet extends HttpServlet {

    // ...

}

或者,当尚未使用Servlet 3.0兼容容器(Tomcat 7Glassfish 3JBoss AS 6等或更新版本)时,请以web.xml旧式进行映射:

<servlet>

    <servlet-name>someservlet</servlet-name>

    <servlet-class>com.example.SomeServlet</servlet-class>

</servlet>

<servlet-mapping>

    <servlet-name>someservlet</servlet-name>

    <url-pattern>/someservlet/*</url-pattern>

</servlet-mapping>

现在在浏览器中打开http// localhost8080 / context / some.jsp,然后按按钮。将看到,使用servlet响应更新了的div内容。

原文地址:https://www.cnblogs.com/woniuxy/p/7428779.html