@WebServlet("/greeting") //以@WebServlet注释开头，注释指定相对于上下文根的URL模式，即在根目录下使用/greeting来访问
public class GreetingServlet extends HttpServlet {
@Override
public void doGet(HttpServletRequest request, //该servlet重写该doGet方法，实现GET HTTP方法
HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html"); //指定响应页面的类型为html
response.setBufferSize(8192); //指定缓冲区大小
try (PrintWriter out = response.getWriter()) { //实例化对象out,作为向html页面输出的对象
//使用println属性，向html页面输出html标签,这里输出的是：
//<html lang=en>
// <head>
// <title>Servlet Hello</title>
// </head>
out.println("<html lang="en">"
+ "<head><title>Servlet Hello</title></head>");
//使用println属性，向html页面输出html标签,这里输出的是：
//<body bgcolor=#ffffff>
// <img src=resources/images/duke.waving.gif alt=Duke waving his hand>
// <form method=get>
// <h2>Hello, my name is Duke. What's yours?</h2>
// <input title=My name is: type=text name=username size=25/>
// <p></p>
// <input type=submit value=Submit/>
// <input type=reset value=Reset/>
// </form>)
out.println("<body bgcolor="#ffffff">"
+ "<img src="resources/images/duke.waving.gif" "
+ "alt="Duke waving his hand">"
+ "<form method="get">"
+ "<h2>Hello, my name is Duke. What's yours?</h2>"
+ "<input title="My name is: " type="text" "
+ "name="username" size="25"/>"
+ "<p></p>"
+ "<input type="submit" value="Submit"/>"
+ "<input type="reset" value="Reset"/>"
+ "</form>");
//使用一个字符串username来获取，第一个input标签内的username的值
String username = request.getParameter("username");
if (username != null && username.length() > 0) {
RequestDispatcher dispatcher =
getServletContext().getRequestDispatcher("/response");
//指定要跳转的页面相对于上下文根的URL模式为/response
if (dispatcher != null) {
//整合request, response然后跳转
dispatcher.include(request, response);
}
}
//使用println属性，向html页面输出html标签,这里输出的是：
// </body>
//</html>
out.println("</body></html>");
}
}
@Override
public String getServletInfo() {
return "The Hello servlet says hello.";
}
}