JSP 中Servlet的自己实现

一步骤

1、继承HttpServlet
2、重写doGet()或者doPost()方法
3、在web.xml中注册Servlet

二 HttpServlet类继承图

三实例

1、创建MyFirstServletDemo web project.

2、编辑index.jsp

<%@ page language=\”java\” import=\”java.util.*\” contentType=\”text/html; charset=utf-8\”%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+\”://\”+request.getServerName()+\”:\”+request.getServerPort()+path+\”/\”;
%>

<!DOCTYPE HTML PUBLIC \”-//W3C//DTD HTML 4.01 Transitional//EN\”>
<html>
<head>
<base href=\”<%=basePath%>\” rel=\”external nofollow\” >

<title>My JSP \’index.jsp\’ starting page</title>
<meta http-equiv=\”pragma\” content=\”no-cache\”>
<meta http-equiv=\”cache-control\” content=\”no-cache\”>
<meta http-equiv=\”expires\” content=\”0\”>
<meta http-equiv=\”keywords\” content=\”keyword1,keyword2,keyword3\”>
<meta http-equiv=\”description\” content=\”This is my page\”>
<!–
<link rel=\”stylesheet\” type=\”text/css\” href=\”styles.css\” rel=\”external nofollow\” >
–>
</head>

<body>
<h1>第一个Servlet小例子</h1>
<a href=\”servlet/HelloServlet\” rel=\”external nofollow\” >Get方式请求HelloServlet</a>
<form action=\”servlet/HelloServlet\” method=\”post\”>
<input type=\”submit\” value=\”Post方式请求HelloServlet\”>
</form>
</body>
</html>

3、编写HelloServlet

package servlet;

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;

//继承于HttpServlet
public class HelloServlet extends HttpServlet {

@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
// TODO Auto-generated method stub
System.out.println(\”处理get（）请求…\”);
PrintWriter out = response.getWriter();
response.setContentType(\”text/html; charset=utf-8\”);
out.println(\”<strong>Hello Servlet!</strong><br>\”);
}

@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
System.out.println(\”处理post（）请求…\”);
PrintWriter out = response.getWriter();
response.setContentType(\”text/html; charset=utf-8\”);
out.println(\”<strong>Hello Servlet!</strong><br>\”);
}

}

4、编写web.xml

<?xml version=\”1.0\” encoding=\”UTF-8\”?>
<web-app version=\”2.5\”
xmlns=\”http://java.sun.com/xml/ns/javaee\”;
xmlns:xsi=\”http://www.w3.org/2001/XMLSchema-instance\”;
xsi:schemaLocation=\”http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd\”;>
<display-name></display-name>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
<servlet>
<servlet-name>HelloServlet</servlet-name>
<servlet-class>servlet.HelloServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>HelloServlet</servlet-name>
<url-pattern>/servlet/HelloServlet</url-pattern>
</servlet-mapping>
</web-app>