Servlet小例子

1.首页面

<%@ page language="java" contentType="text/html; charset=UTF-8"
	pageEncoding="UTF-8"%>
<html>
	<head>
		<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
		<title>Test测试</title>
	</head>
	<body>
		<form action="/test/hello" method="post">
			请输入名称：
			<input type="text" name="yourname" value=""/>
			<br/>
			<input type="submit" value="提交"/>
		</form>
<br/>
<br/>
		<form action="/test/hello" method="get">
			请输入名称：
			<input type="text" name="yourname" value=""/>
			<br/>
			<input type="submit" value="提交"/>
		</form>
<br/>
<br/>
		<form action="/test/login" method="get">
			用户名：
			<input type="text" name="username" value=""/>
			<br/>
			密码：
			<input type="text" name="password" value=""/>
			<br/>
			<input type="submit" value="提交"/>
		</form>
	</body>
</html>

2.Hello类可以处理中文

package com.test;

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 Hello extends HttpServlet {
	private static final long serialVersionUID = 8905488072908091282L;

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

		String yourname = request.getParameter("yourname");
		String welcome = "";
		if (yourname != null && !yourname.trim().equals("")) {
			welcome = "Get Hello 显示:" + new String(yourname.getBytes("ISO-8859-1"), "UTF-8");
		}
		System.out.println(welcome);
		response.setCharacterEncoding("UTF-8");
		PrintWriter out = response.getWriter();
		out.println("<html><head><title>");
		out.println("欢迎页Welcome");
		out.println("</title></head><body><h1>");
		out.println(welcome);
		out.println("</h1></body></html>");
		out.close();
	}

	public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

		request.setCharacterEncoding("UTF-8");
		String yourname = request.getParameter("yourname");
		String welcome = "Post Hello 显示:" + yourname;
		System.out.println(welcome);

		response.setCharacterEncoding("UTF-8");
		PrintWriter out = response.getWriter();
		out.println("<html><head><title>");
		out.println("欢迎页Welcome");
		out.println("</title></head><body><h1>");
		out.println(welcome);
		out.println("</h1></body></html>");
		out.close();
	}
}

3.Login类

package com.test;

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 Login extends HttpServlet {
	private static final long serialVersionUID = 8905488072908091282L;

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

		String username = request.getParameter("username");
		String password = request.getParameter("password");
		if (username != null && username.trim().equals("admin") && password != null && password.trim().equals("123456")) {
			request.getSession().setAttribute("user", username);
			response.sendRedirect("main.jsp");
		} else {
			response.sendError(HttpServletResponse.SC_SERVICE_UNAVAILABLE, "用户名或密码错误！");
		}
	}

	public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

		doGet(request, response);
	}
}

4.Web.xml

<web-app version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
	<display-name>TEST</display-name>
	<servlet>
		<servlet-name>hello</servlet-name>
		<servlet-class>com.test.Hello</servlet-class>
	</servlet>
	<servlet>
		<servlet-name>login</servlet-name>
		<servlet-class>com.test.Login</servlet-class>
	</servlet>
	<servlet-mapping>
		<servlet-name>hello</servlet-name>
		<url-pattern>/hello</url-pattern>
	</servlet-mapping>
	<servlet-mapping>
		<servlet-name>login</servlet-name>
		<url-pattern>/login</url-pattern>
	</servlet-mapping>
</web-app>

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