WBE15_HttpServletRequest

1．HttpServletRequest概述

我们在创建Servlet时会覆盖service()方法，或doGet()/doPost(),这些方法都有两个参数，一个为代表请求的request和代表响应response。

service方法中的request的类型是ServletRequest，而doGet/doPost方法的request的类型是HttpServletRequest，HttpServletRequest是ServletRequest的子接口，功能和方法更加强大，今天我们学习HttpServletRequest。

2．request的运行流程

3．通过抓包工具抓取Http请求

因为request代表请求，所以我们可以通过该对象分别获得Http请求的请求行，请 求头和请求体

4．通过request获得请求行

获得客户端的请求方式：String getMethod()

获得请求的资源：

String getRequestURI() 

StringBuffer getRequestURL() 

String getContextPath() ---web应用的名称

String getQueryString() ---- get提交url地址后的参数字符串

username=zhangsan&password=123

注意：

request获得客户机（客户端）的一些信息

request.getRemoteAddr() --- 获得访问的客户端IP地址

//1、获得请求方式
		String method = request.getMethod();
		System.out.println("method:" + method);
		//2.获得请求的资源相关的内容
		String requestURI = request.getRequestURI();
		System.out.println("uri:"+requestURI);
		StringBuffer requestURL = request.getRequestURL();
		System.out.println("url:"+requestURL);
		//获得Web应用的名称
		String contextPath = request.getContextPath();
		System.out.println("web应用：" + contextPath);
		//地址后的参数字符串
		String queryString = request.getQueryString();
		System.out.println(queryString);
		//3.获得客户端的信息--获得访问者的IP地址
		String remoteAddr = request.getRemoteAddr();
		System.out.println(remoteAddr);

method:post

5．通过request获得请求头

long getDateHeader(String name)

String getHeader(String name)

Enumeration getHeaderNames()

Enumeration getHeaders(String name)

int getIntHeader(String name)

//1.获得指定的头
		String header = request.getHeader("User-Agent");
		System.out.println(header);
		//2.获得所有头的名称
		Enumeration<String> headerNames = request.getHeaderNames();
		while(headerNames.hasMoreElements()){
			String headerName = headerNames.nextElement();
			String headerValue = request.getHeader(headerName);
			System.out.println(headerName + ":" + headerValue);
		}

输出：

Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:65.0) Gecko/20100101 Firefox/65.0
host:localhost:8080
user-agent:Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:65.0) Gecko/20100101 Firefox/65.0
accept:text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8
accept-language:zh-CN,zh;q=0.8,zh-TW;q=0.7,zh-HK;q=0.5,en-US;q=0.3,en;q=0.2
accept-encoding:gzip, deflate
connection:keep-alive
upgrade-insecure-requests:1

referer头的作用：执行该此访问的的来源

做防盗链

//对新闻的来源进行判断
		String header = request.getHeader("referer");
		if(header != null && header.startsWith("http://localhost")){
			//从自己网站跳转过来,可以看新闻
			response.setContentType("text/html;charset=UTF-8");
			response.getWriter().write("奖牌");
		}else{
			response.setContentType("text/html;charset=UTF-8");
			response.getWriter().write("盗链者,可耻");
		}

6．通过request获得请求体

请求体中的内容是通过post提交的请求参数，格式是：
username=zhangsan&password=123&hobby=football&hobby=basketball
key ---------------------- value
username [zhangsan]
password [123]
hobby [football，basketball]

以上面参数为例，通过一下方法获得请求参数：
String getParameter(String name)
String[] getParameterValues(String name)
Enumeration getParameterNames()
Map<String,String[]> getParameterMap()

注意：get请求方式的请求参数 上述的方法一样可以获得

  解决post提交方式的乱码：request.setCharacterEncoding("UTF-8");
  解决get提交的方式的乱码：
        parameter = new String(parameter.getbytes("iso8859-1"),"utf-8");

//1.获得单个表单值
		String username = request.getParameter("username");
		System.out.println(username);//zhangsan
		String password = request.getParameter("password");
		System.out.println(password);//123
		//2.获得多个表单的值
		String[] hobbys = request.getParameterValues("hobby");
		for(String hobby : hobbys){
			System.out.println(hobby);
		}
		//3.获得所有请求参数的名称
		Enumeration<String> parameterNames = request.getParameterNames();
		while(parameterNames.hasMoreElements()){
			System.out.println(parameterNames.nextElement());
		}
		System.out.println("---------------------------");
		Map<String, String[]> parameterMap = request.getParameterMap();
		for(Map.Entry<String, String[]> entry : parameterMap.entrySet()){
			System.out.println(entry.getKey());
			for(String str : entry.getValue()){
				System.out.println(str);
			}
			System.out.println("---------------------------");
		}

7．request的其他功能

(1) request是一个域对象

request对象也是一个存储数据的区域对象，所以也具有如下方法：
setAttribute(String name, Object o)
getAttribute(String name)
removeAttribute(String name)

注意：request域的作用范围：一次请求中（重定向就没有数据,原因还是出在只在一次请求中，而重定向是两次请求）

(2) request完成请求转发

获得请求转发器----path是转发的地址

RequestDispatcher getRequestDispatcher(String path)

通过转发器对象转发

requestDispathcer.forward(ServletRequest request, ServletResponse response)

注意：ServletContext域与Request域的生命周期比较？

		ServletContext：
			创建：服务器启动
			销毁：服务器关闭
			域的作用范围：整个web应用
		request：
			创建：访问时创建request
			销毁：响应结束request销毁
			域的作用范围：一次请求中

注意：转发与重定向的区别？

		1）重定向两次请求，转发一次请求
		2）重定向地址栏的地址变化，转发地址不变
		3）重新定向可以访问外部网站 转发只能访问内部资源
		4）转发的性能要优于重定向

Servlet1

        //想request域中存储数据
		request.setAttribute("name", "tom");
		
		//将servlet1请求转发给servlet2
		RequestDispatcher requestDispatcher = request.getRequestDispatcher("/servlet2");
		//执行转发的方法
		requestDispatcher.forward(request, response);

Servlet2

        //从request域中取出数据
		Object attribute = request.getAttribute("name");
		response.getWriter().write("hello haohao..." + attribute);

注意：客户端地址与服务器端地址的写法？

		客户端地址：
			是客户端去访问服务器的地址，服务器外部的地址，
			特点：写上web应用名称			
			直接输入地址：
			重定向
			
		服务器端地址：
			服务器内部资源的跳转的地址，
			特点：不需要写web应用的名称
			转发

案例一、完成用户注册

/WEB15A/WebContent/register.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
	pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head></head>
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>会员注册</title>
<link rel="stylesheet" href="css/bootstrap.min.css" type="text/css" />
<script src="js/jquery-1.11.3.min.js" type="text/javascript"></script>
<script src="js/bootstrap.min.js" type="text/javascript"></script>
<!-- 引入自定义css文件 style.css -->
<link rel="stylesheet" href="css/style.css" type="text/css" />

<style>
body {
	margin-top: 20px;
	margin: 0 auto;
}

.carousel-inner .item img {
	width: 100%;
	height: 300px;
}

font {
	color: #3164af;
	font-size: 18px;
	font-weight: normal;
	padding: 0 10px;
}
</style>
</head>
<body>

	<!-- 引入header.jsp -->
	<jsp:include page="/header.jsp"></jsp:include>

	<div class="container"
		style="width: 100%; background: url('image/regist_bg.jpg');">
		<div class="row">
			<div class="col-md-2"></div>
			<div class="col-md-8"
				style="background: #fff; padding: 40px 80px; margin: 30px; border: 7px solid #ccc;">
				<font>会员注册</font>USER REGISTER
				<!-- 当你点击button按钮提交的时候，浏览器的地址为/WEB15/register，页面会刷新但是地址不变 -->
				<form class="form-horizontal" style="margin-top: 5px;" action="/WEB15A/register" method="post">
					<div class="form-group">
						<label for="username" class="col-sm-2 control-label">用户名</label>
						<div class="col-sm-6">
							<input type="text" class="form-control" id="username" name="username" 
								placeholder="请输入用户名">
						</div>
					</div>
					<div class="form-group">
						<label for="inputPassword3" class="col-sm-2 control-label">密码</label>
						<div class="col-sm-6">
							<input type="password" class="form-control" id="inputPassword3" name="password"
								placeholder="请输入密码">
						</div>
					</div>
					<div class="form-group">
						<label for="confirmpwd" class="col-sm-2 control-label">确认密码</label>
						<div class="col-sm-6">
							<input type="password" class="form-control" id="confirmpwd"
								placeholder="请输入确认密码">
						</div>
					</div>
					<div class="form-group">
						<label for="inputEmail3" class="col-sm-2 control-label">Email</label>
						<div class="col-sm-6">
							<input type="email" class="form-control" id="inputEmail3" name="email"
								placeholder="Email">
						</div>
					</div>
					<div class="form-group">
						<label for="usercaption" class="col-sm-2 control-label">姓名</label>
						<div class="col-sm-6">
							<input type="text" class="form-control" id="usercaption" name="name"
								placeholder="请输入姓名">
						</div>
					</div>
					<div class="form-group opt">
						<label for="inlineRadio1" class="col-sm-2 control-label">性别</label>
						<div class="col-sm-6">
							<label class="radio-inline"> <input type="radio"
								name="sex" id="inlineRadio1" value="male">
								男
							</label> <label class="radio-inline"> <input type="radio"
								name="sex" id="inlineRadio2" value="female">
								女
							</label>
						</div>
					</div>
					<div class="form-group">
						<label for="date" class="col-sm-2 control-label">出生日期</label>
						<div class="col-sm-6">
							<input type="date" class="form-control" name="birthday">
						</div>
					</div>

					<div class="form-group">
						<label for="date" class="col-sm-2 control-label">验证码</label>
						<div class="col-sm-3">
							<input type="text" class="form-control">

						</div>
						<div class="col-sm-2">
							<img src="./image/captcha.jhtml" />
						</div>

					</div>

					<div class="form-group">
						<div class="col-sm-offset-2 col-sm-10">
							<input type="submit" width="100" value="注册" name="submit"
								style="background: url('./images/register.gif') no-repeat scroll 0 0 rgba(0, 0, 0, 0); height: 35px; width: 100px; color: white;">
						</div>
					</div>
				</form>
			</div>

			<div class="col-md-2"></div>

		</div>
	</div>

	<!-- 引入footer.jsp -->
	<jsp:include page="/footer.jsp"></jsp:include>

</body>
</html>

/WEB15A/src/cn/ithiema/register/RegisterServlet.java

package cn.ithiema.register;

import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.sql.SQLException;
import java.util.Map;
import java.util.UUID;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.beanutils.BeanUtils;
import org.apache.commons.dbutils.QueryRunner;

import cn.ithiema.utils.DataSourceUtils;

public class RegisterServlet extends HttpServlet {

	public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		
		//设置request的编码---只适合post方式
		request.setCharacterEncoding("UTF-8");
		
		//get方式乱码解决
		//String username = request.getParameter("username");//乱码
		//先用iso8859-1编码 在使用utf-8解码
		//username = new String(username.getBytes("iso8859-1"),"UTF-8");
		
		
		//1、获取数据
		String username = request.getParameter("username");
		System.out.println(username);
		//String password = request.getParameter("password");
		//.....

		//2、将散装的封装到javaBean
		//User user = new User();
		//user.setUsername(username);
		//user.setPassword(password);

		//使用BeanUtils进行自动映射封装
		//BeanUtils工作原理：将map中的数据 根据key与实体的属性的对应关系封装
		//只要key的名字与实体的属性 的名字一样 就自动封装到实体中
		Map<String, String[]> properties = request.getParameterMap();
		User user = new User();
		try {
			BeanUtils.populate(user, properties);
		} catch (IllegalAccessException | InvocationTargetException e) {
			e.printStackTrace();
		}

		//现在这个位置 user对象已经封装好了
		//手动封装uid----uuid---随机不重复的字符串32位--java代码生成后是36位
		user.setUid(UUID.randomUUID().toString());

		//3、将参数传递给一个业务操作方法
		try {
			regist(user);
		} catch (SQLException e) {
			e.printStackTrace();
		}
		
		//4、认为注册成功跳转到登录页面
		//response.sendRedirect(request.getContextPath()+"/login.jsp");
	}

	//注册的方法
	public void regist(User user) throws SQLException{
		//操作数据库
		QueryRunner runner = new QueryRunner(DataSourceUtils.getDataSource());
		String sql = "insert into user values(?,?,?,?,?,?,?,?,?,?)";
		
		runner.update(sql,user.getUid(),user.getUsername(),user.getPassword(),user.getName(),
				user.getEmail(),null,user.getBirthday(),user.getSex(),null,null);
	}
	
	public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		doGet(request, response);
	}
}

/WEB15A/src/cn/ithiema/register/User.java

package cn.ithiema.register;

public class User {
	private String uid;
	private String username;
	private String password;
	private String name;
	private String email;
	private String sex;
	private String birthday;
	public String getUid() {
		return uid;
	}
	public void setUid(String uid) {
		this.uid = uid;
	}
	public String getUsername() {
		return username;
	}
	public void setUsername(String username) {
		this.username = username;
	}
	public String getPassword() {
		return password;
	}
	public void setPassword(String password) {
		this.password = password;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public String getEmail() {
		return email;
	}
	public void setEmail(String email) {
		this.email = email;
	}
	public String getSex() {
		return sex;
	}
	public void setSex(String sex) {
		this.sex = sex;
	}
	public String getBirthday() {
		return birthday;
	}
	public void setBirthday(String birthday) {
		this.birthday = birthday;
	}
	@Override
	public String toString() {
		return "User [uid=" + uid + ", username=" + username + ", password=" + password + ", name=" + name + ", email="
				+ email + ", sex=" + sex + ", birthday=" + birthday + "]";
	}
	
	
}

注册乱码的解决：

当method=“post”，
//设置request的编码—只适合post方式
//request.setCharacterEncoding(“UTF-8”);
乱码的情况：


当method=“get”，
//设置request的编码—只适合post方式
//request.setCharacterEncoding(“UTF-8”);
乱码的情况：

//get方式乱码解决
String username = request.getParameter("username");//乱码
//先用iso8859-1编码 在使用utf-8解码
username = new String(username.getBytes("iso8859-1"),"UTF-8");
System.out.println(username);

案例二、完成登录错误信息的回显

<%@ page language="java" contentType="text/html; charset=UTF-8"
	pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>会员登录</title>
<link rel="stylesheet" href="css/bootstrap.min.css" type="text/css" />
<script src="js/jquery-1.11.3.min.js" type="text/javascript"></script>
<script src="js/bootstrap.min.js" type="text/javascript"></script>
<!-- 引入自定义css文件 style.css -->
<link rel="stylesheet" href="css/style.css" type="text/css" />

<style>
body {
	margin-top: 20px;
	margin: 0 auto;
}

.carousel-inner .item img {
	width: 100%;
	height: 300px;
}

.container .row div {
	/* position:relative;
				 float:left; */
	
}

font {
	color: #666;
	font-size: 22px;
	font-weight: normal;
	padding-right: 17px;
}
</style>
</head>
<body>

	<!-- 引入header.jsp -->
	<jsp:include page="/header.jsp"></jsp:include>


	<div class="container"
		style="width: 100%; height: 460px; background: #FF2C4C url('images/loginbg.jpg') no-repeat;">
		<div class="row">
			<div class="col-md-7">
				<!--<img src="./image/login.jpg" width="500" height="330" alt="会员登录" title="会员登录">-->
			</div>

			<div class="col-md-5">
				<div
					style="width: 440px; border: 1px solid #E7E7E7; padding: 20px 0 20px 30px; border-radius: 5px; margin-top: 60px; background: #fff;">
					<font>会员登录</font>USER LOGIN
					<div><%=request.getAttribute("loginInfo")==null?"":request.getAttribute("loginInfo") %></div>
					<form class="form-horizontal" action="/WEB15/login" method="post">
						<div class="form-group">
							<label for="username" class="col-sm-2 control-label">用户名</label>
							<div class="col-sm-6">
								<input type="text" class="form-control" id="username" name="username"
									placeholder="请输入用户名">
							</div>
						</div>
						<div class="form-group">
							<label for="inputPassword3" class="col-sm-2 control-label">密码</label>
							<div class="col-sm-6">
								<input type="password" class="form-control" id="inputPassword3" name="password"
									placeholder="请输入密码">
							</div>
						</div>
						<div class="form-group">
							<label for="inputPassword3" class="col-sm-2 control-label">验证码</label>
							<div class="col-sm-3">
								<input type="text" class="form-control" id="inputPassword3"
									placeholder="请输入验证码">
							</div>
							<div class="col-sm-3">
								<img src="./image/captcha.jhtml" />
							</div>
						</div>
						<div class="form-group">
							<div class="col-sm-offset-2 col-sm-10">
								<div class="checkbox">
									<label> <input type="checkbox"> 自动登录
									</label>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <label> <input
										type="checkbox"> 记住用户名
									</label>
								</div>
							</div>
						</div>
						<div class="form-group">
							<div class="col-sm-offset-2 col-sm-10">
								<input type="submit" width="100" value="登录" name="submit"
									style="background: url('./images/login.gif') no-repeat scroll 0 0 rgba(0, 0, 0, 0); height: 35px; width: 100px; color: white;">
							</div>
						</div>
					</form>
				</div>
			</div>
		</div>
	</div>

	<!-- 引入footer.jsp -->
	<jsp:include page="/footer.jsp"></jsp:include>

</body>
</html>

package cn.ithiema.login;

import java.io.IOException;
import java.sql.SQLException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.BeanHandler;

import cn.ithiema.register.User;
import cn.ithiema.utils.DataSourceUtils;

public class LoginServlet extends HttpServlet {

	public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		//设置request的编码---只适合post方式
		request.setCharacterEncoding("UTF-8");
		
		//1.获得用户名和密码
		String username = request.getParameter("username");
		String password = request.getParameter("password");
		//2.调用一个业务方法进行该用户查询
		User login = null;
		try {
			login = login(username, password);
		} catch (Exception e) {
			System.out.println(e);
		}
		//3.通过user是否为null,判断用户名和密码是否正确
		if(login != null){
			//用户名和密码正确
			//登录成功,跳转到网站的首页
			response.sendRedirect(request.getContextPath());
		}else{
			//用户名或密码错误
			//跳回当前login.jsp
			//使用转发,转发到login.jsp 向request域中存储错误信息
			request.setAttribute("loginInfo", "用户名或密码错误");
			request.getRequestDispatcher("/login.jsp").forward(request, response);
		}
		
	}
	public User login(String username,String password){
		User user = null;
		try {
			QueryRunner runner = new QueryRunner(DataSourceUtils.getDataSource());
			String sql = "select * from user where username=? and password=?";
			user = runner.query(sql, new BeanHandler<User>(User.class),username,password);
		} catch (SQLException e) {		
			e.printStackTrace();
		}
		return user;
	}
	
	public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		doGet(request, response);
	}
}

注册界面


登录成功

总结：

request获得行的内容

request.getMethod()
request.getRequestURI()
request.getRequestURL()
request.getContextPath()
request.getRemoteAddr()

request获得头的内容

request.getHeader(name)

request获得体（请求参数）

String request.getParameter(name)
Map<String,String[]> request.getParameterMap();
String[] request.getParameterValues(name);
注意：客户端发送的参数 到服务器端都是字符串

获得中文乱码的解决：

post:request.setCharacterEncoding(“UTF-8”);
get:
//get方式乱码解决
String username = request.getParameter("username");//乱码
//先用iso8859-1编码 在使用utf-8解码
username = new String(username.getBytes("iso8859-1"),"UTF-8");

request转发和域

request.getRequestDispatcher(转发的地址).forward(req,resp);
request.setAttribute(name,value)
request.getAttribute(name)