HttpServletRequest介绍和使用

偏执的太偏执、 2023-10-01 20:17 31阅读 0赞

## 基本介绍 ##

httpServletRequest对象对http请求进行了封装，我们使用这个对象就可以方便快捷的获取http中的信息。HttpServletRequest 对象代表客户端的请求，在里面就包含了所有的客服端信息，我们通过这个对象的方法便可以获取所有的客服端信息，包括请求头和请求体中的所有数据。

## 常见方法 ##

*  getRequestURL()：得到请求的URI
 *  getRequestURL()：得到请求的URL
 *  getHeader(String s)：getHeader表示得到请求头，参数s表示想要获取请求头中的什么数据
 *  getHeader("Host")：获取请求的主机
 *  getHeader("Referer")：获取请求来自于哪里，一般用来做防盗链
 *  getRemotetAddr()：得到请求的ip
 *  getParameter(String s)：得到请求参数的值
 *  getParameterValues(String s)：得到请求参数的值，用于参数有多个值，返回一个数组

--------------------

## 方法演示 ##

**我们创建一个注册页面来提交数据，服务器将获取数据并进行展示，代码如下**

<!DOCTYPE html>
    <html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>登录</title>
    </head>
    <body>
    <form action="http://localhost:8080/servlet/requestTest" method="post">
        用户名:<input type="text" name="username"> <br>
        密　码:<input type="password" name="password"><br>
        爱好 <input type="checkbox" name="hobby" value="lq">篮球
        <input type="checkbox" name="hobby" value="zq">足球
        <input type="checkbox" name="hobby" value="pq">排球<br>
        <input type="submit" value="注册">
    </form>
    </body>
    </html>

import javax.servlet.*;
    import javax.servlet.annotation.WebServlet;
    import javax.servlet.http.*;
    import java.io.IOException;
    import java.util.Arrays;
    
    @WebServlet("/requestTest")
    public class HttpServletRequestTest extends HttpServlet {
        @Override
        protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
            //得到请求URL
            StringBuffer requestURL = request.getRequestURL();
            System.out.println("请求的URL是：" + requestURL);
            //得到请求URI
            String requestURI = request.getRequestURI();
            System.out.println("请求的URI是：" + requestURI);
            //得到主机名Host
            String host = request.getHeader("Host");
            System.out.println("请求的主机名是：" + host);
            //得到请求的ip
            String ip = request.getRemoteAddr();
            System.out.println(ip);
            //得到请求参数，分别得到用户名，密码还有爱好
            //如果参数中有中文，需要设置编码
            request.setCharacterEncoding("utf-8");
            String username = request.getParameter("username");
            String password = request.getParameter("password");
            String[] hobbies = request.getParameterValues("hobby");
            System.out.println("用户名为：" + username);
            System.out.println("密码：" + password);
            System.out.println("爱好为：" + Arrays.toString(hobbies));
            //得到访问来自哪里
            String referer = request.getHeader("Referer");
            System.out.println("请求来自于：" + referer);
        }
    
        @Override
        protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
            this.doGet(request, response);
        }
    }

下面是我们提交的数据

![watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBA5LiN5pyN6L6T55qE5bCR5bm0_size_15_color_FFFFFF_t_70_g_se_x_16][]

**抓包进行查看**

**请求头**

POST /servlet/requestTest HTTP/1.1
    Host: localhost:8080
    Connection: keep-alive
    Content-Length: 60
    Cache-Control: max-age=0
    sec-ch-ua: " Not A;Brand";v="99", "Chromium";v="98", "Google Chrome";v="98"
    sec-ch-ua-mobile: ?0
    sec-ch-ua-platform: "Windows"
    Upgrade-Insecure-Requests: 1
    Origin: http://localhost:8080
    Content-Type: application/x-www-form-urlencoded
    User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/98.0.4758.102 Safari/537.36
    Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9
    Sec-Fetch-Site: same-origin
    Sec-Fetch-Mode: navigate
    Sec-Fetch-User: ?1
    Sec-Fetch-Dest: document
    Referer: http://localhost:8080/servlet/register_request.html
    Accept-Encoding: gzip, deflate, br
    Accept-Language: zh-CN,zh;q=0.9
    Cookie: JSESSIONID=ABEC5EA43080A0BFA70C2AABDF39BB7C; Pycharm-cb145b54=bac13d99-2d7f-4b5f-9c85-e783571ee72d; Idea-8cd34e8b=1bf6d6e0-14ee-4950-96ec-48105743bb40

**请求体**

![watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBA5LiN5pyN6L6T55qE5bCR5bm0_size_20_color_FFFFFF_t_70_g_se_x_16][]

**我们查看控制台输出**

![watermark_type_d3F5LXplbmhlaQ_shadow_50_text_Q1NETiBA5LiN5pyN6L6T55qE5bCR5bm0_size_20_color_FFFFFF_t_70_g_se_x_16 1][]

**发现完全一样，我们可以通过HttpServletRequest获取http请求的所有信息。 HttpServletRequest方法众多，想要了解查看Api文档即可**

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