Servlet 是 Java 服务端程序，Servlet 程序是运行在服务器上的
Seervlet 程序代码：
package g.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;public class HelloWorldServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {response.setContentType("text/html");
PrintWriter out = response.getWriter();
out.println("<html><head><title>Hello World</title></head>");
out.println("<body><h1>hello, world</h1></body><html>");
out.println("<br>" + new java.util.Date().toString());
out.flush();
}
}
web.xml 设置：
<servlet>
<servlet-name>HelloWorld</servlet-name>
<servlet-class>g.servlet.HelloWorldServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>HelloWorld</servlet-name>
<url-pattern>/HelloWorld</url-pattern>
</servlet-mapping>
浏览器访问：
http://localhost:8080/JavaWeb/HelloWorld
即可
新建 JSP 文件 HelloWorld.jsp：
<%@page import="java.util.Date"%>
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<h1>hello, world</h1>
<%= new Date().toString() %>
</body>
</html>
浏览器访问：
http://localhost:8080/JavaWeb/HelloWorld.jsp
即可
一个用户登录程序
LoginServlet：
package g.servlet;import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;public class LoginServlet extends HttpServlet {
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doPost(request, response);
}public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {String username = request.getParameter("username");
String password = request.getParameter("password");System.out.println(username + ":" + password);
}
}
login.jsp：
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Login</title>
</head>
<body>
<form action="LoginServlet" method="post">
username:<input type="text" name="username">
password:<input type="password" name="password">
<input type="submit" value="submit">
<input type="reset" value="reset">
</form></body>
</html>
web.xml 配置：
<servlet>
<servlet-name>LoginServlet</servlet-name>
<servlet-class>g.servlet.LoginServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>LoginServlet</servlet-name>
<url-pattern>/LoginServlet</url-pattern>
</servlet-mapping>
GET 和 POST 的区别：
get，默认方式：
GET /LoginServlet?username=user&password=pass HTTP/1.1
post：（文件上传必须用 post）
POST /LoginServlet HTTP/1.1
两者向服务器端发送请求时的形式是不同的
Java Web(2)：第一个 Servlet 程序,布布扣,bubuko.com