HTTP之request请求

Posted 2022-01-03 hejh

HTTP之request请求

 

request:请求
    作用:获取浏览器发送过来的数据
    组成部分:
        请求行 请求头 请求体
    操作请求行 
        格式:
            请求方式 请求资源 协议/版本
        常用方法:HttpServletRequest
            掌握
                String getMethod():获取请求方式
                String getRemoteAddr():获取ip地址
                String getContextPath() :在java中获取项目名称  (/day10)
 
            
            了解:
                getRequestURI():获取的是 从项目名到参数之前的内容  /day10/regist
                getRequestURL():获取的带协议的完整路径   http://localhost/day10/regist
                String getQueryString():get请求的所有参数   username=tom&password=123
                String getProtocol():获取协议和版本
                
        例如:请求行
            GET /day10/row?username=tom&password=123 HTTP/1.1

 

案例：请求头方法

 

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd" id="WebApp_ID" version="3.1">
 
  <servlet>
    <servlet-name>RowServlet</servlet-name>
    <servlet-class>com.hjh.servlet.request.RowServlet</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>RowServlet</servlet-name>
    <url-pattern>/row</url-pattern>
  </servlet-mapping>
  
</web-app>

 

 

package com.hjh.servlet.request;

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 RowServlet extends HttpServlet 
    private static final long serialVersionUID = 1L;
    
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException 
        //获取请求方式
        String method = request.getMethod();
        System.out.println("请求方式："+method);
        
        //获取请求资源
        String uri = request.getRequestURI();
        String url = request.getRequestURL().toString();
        System.out.println("uri："+uri+"                "+" url："+url);
        
        //获取请求参数的字符串
        String query = request.getQueryString();
        System.out.println("请求参数字符串："+query);
        
        //获取协议版本
        String protocol = request.getProtocol();
        System.out.println("协议版本："+protocol);
        
        System.out.println("---------------------------以下为重要方法----------------------------");
        
        //获取请求IP
        String addr = request.getRemoteAddr();
        System.out.println("请求IP:"+addr);
        
        //获取项目名
        String contextPath = request.getContextPath();
        System.out.println("项目名："+contextPath);        
    

    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException 
        doGet(request, response);
    

 

 

启动项目，浏览器输入url“http://localhost:8080/Servlet/row?username=hjh&password=12345”，回车，eclipse中console输出为：

请求方式：GET
uri：/Servlet/row                 url：http://localhost:8080/Servlet/row
请求参数字符串：username=hjh&password=12345
协议版本：HTTP/1.1
---------------------------以下为重要方法----------------------------
请求IP:0:0:0:0:0:0:0:1
项目名：/Servlet

 

 

 

操作请求头 
        格式:key/value(value可以是多个值)
        常用方法:
            ★String getHeader(String key):通过key获取指定的value (一个)
            
            了解:
                Enumeration getHeaders(String name) :通过key获取指定的value(多个)
                Enumeration getHeaderNames() :获取所有的请求头的名称
                int getIntHeader(String key):获取整型的请求头
                long getDateHeader(String key):获取时间的请求头
        重要的请求头:
            user-agent:浏览器内核 msie firefox chrome
            referer:页面从那里来 防盗链

案例：请求头

 <servlet>
    <servlet-name>HeaderServlet</servlet-name>
    <servlet-class>com.hjh.servlet.request.HeaderServlet</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>HeaderServlet</servlet-name>
    <url-pattern>/header</url-pattern>
  </servlet-mapping>

 

 

package com.hjh.servlet.request;

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 HeaderServlet extends HttpServlet 
    private static final long serialVersionUID = 1L;

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException 
        //获取浏览器内核
        String user_agent = request.getHeader("user-agent");
        System.out.println("浏览器内核："+user_agent);
        
        //获取referer
        String referer = request.getHeader("referer");
        if(referer==null) 
            System.out.println("直接在地址栏输入的");
        else if(referer.contains("localhost")) 
            System.out.println("本机输入");
        else if(referer.contains("192.167.23.156")) 
            System.out.println("其他人的");
        else 
            System.out.println("兄弟，盗链可耻");
                
    

    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException 
        doGet(request, response);
    

 

 

url   http://localhost:8080/Servlet/header

 

console

浏览器内核：Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (Khtml, like Gecko) Chrome/58.0.3029.96 Safari/537.36
直接在地址栏输入的