文章目录

HTTP：

HTTP：

1. 概念：Hyper Text Transfer Protocol 超文本传输协议

传输协议：定义了，客户端和服务器端通信时，发送数据的格式
特点：
1. 基于TCP/IP的高级协议
2. 默认端口号:80
3. 基于请求/响应模型的:一次请求对应一次响应
4. 无状态的：每次请求之间相互独立，不能交互数据
历史版本：
- 1.0：每一次请求响应都会建立新的连接
- 1.1：复用连接

2. 请求消息数据格式

2.1 请求行

请求方式请求url 请求协议/版本
GET /login.html HTTP/1.1

请求方式：
- HTTP协议有7中请求方式，常用的有2种
  - GET：
    1. 请求参数在请求行中，在url后。
    2. 请求的url长度有限制的
    3. 不太安全
  - POST：
    1. 请求参数在请求体中
    2. 请求的url长度没有限制的
    3. 相对安全

2.2 请求头：客户端浏览器告诉服务器一些信息

请求头名称: 请求头值

常见的请求头：

User-Agent：浏览器告诉服务器，我访问你使用的浏览器版本信息

可以在服务器端获取该头的信息，解决浏览器的兼容性问题
Referer：http://localhost/login.html

告诉服务器，我(当前请求)从哪里来？

作用：
1. 防盗链：
2. 统计工作：

2.3 请求空行

空行，就是用于分割POST请求的请求头，和请求体的。

2.4 请求体(正文)：

封装POST请求消息的请求参数的
字符串格式：

POST /login.html	HTTP/1.1
Host: localhost
User-Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:60.0) Gecko/20100101 Firefox/60.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;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
Referer: http://localhost/login.html
Connection: keep-alive
Upgrade-Insecure-Requests: 1

username=zhangsan

3. 响应消息数据格式

3.1 Request：

在这里插入图片描述

3.1.1 request对象和response对象的原理

request和response对象是由服务器创建的。我们来使用它们
request对象是来获取请求消息，response对象是来设置响应消息

3.1.2 request对象继承体系结构：


ServletRequest	接口
继承
HttpServletRequest	接口
实现

org.apache.catalina.connector.RequestFacade@5b3cad0e
org.apache.catalina.connector.RequestFacade 类(tomcat)

3.1.3 request功能：

3.1.3.1 获取请求消息数据

1. 获取请求行数据

GET /day14/demo1?name=zhangsan HTTP/1.1
方法：
1. 获取请求方式：GET
  String getMethod()
2. (*)获取虚拟目录：/day14
  String getContextPath()
3. 获取Servlet路径: /demo1
  String getServletPath()
4. 获取get方式请求参数：name=zhangsan
  String getQueryString()
5. (*)获取请求URI：/day14/demo1
  String getRequestURI(): /day14/demo1
  StringBuffer getRequestURL() :http://localhost/day14/demo1
  
  URL:统一资源定位符： http://localhost/day14/demo1 中华人民共和国（范围小）
  URI:统一资源标识符 : /day14/demo1 共和国(范围大)
6. 获取协议及版本：HTTP/1.1
  String getProtocol()
7. 获取客户机的IP地址：
  String getRemoteAddr()

package com.example.request;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

/**
 * 演示Request对象获取请求行数据
 */

@WebServlet("/requestDemo1")
public class RequestDemo1 extends HttpServlet {
    
    
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    
    

    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    
    
        /*
            1. 获取请求方式 ：GET
                * String getMethod()
            2. (*)获取虚拟目录：/day14
                * String getContextPath()
            3. 获取Servlet路径: /requestDemo1
                * String getServletPath()
            4. 获取get方式请求参数：name=zhangsan
                * String getQueryString()
            5. (*)获取请求URI：/day14/demo1
                * String getRequestURI():		/day14/requestDemo1
                * StringBuffer getRequestURL()  :http://localhost/day14/requestDemo1
            6. 获取协议及版本：HTTP/1.1
                * String getProtocol()

            7. 获取客户机的IP地址：
                * String getRemoteAddr()

         */
        //1. 获取请求方式 ：GET
        String method = request.getMethod();
        System.out.println(method);
        //2.(*)获取虚拟目录：/day14
        String contextPath = request.getContextPath();
        System.out.println(contextPath);
        //3. 获取Servlet路径: /demo1
        String servletPath = request.getServletPath();
        System.out.println(servletPath);
        //4. 获取get方式请求参数：name=zhangsan
        String queryString = request.getQueryString();
        System.out.println(queryString);
        //5.(*)获取请求URI：/day14/demo1
        String requestURI = request.getRequestURI();
        StringBuffer requestURL = request.getRequestURL();
        System.out.println(requestURI);
        System.out.println(requestURL);
        //6. 获取协议及版本：HTTP/1.1
        String protocol = request.getProtocol();
        System.out.println(protocol);
        //7. 获取客户机的IP地址：
        String remoteAddr = request.getRemoteAddr();
        System.out.println(remoteAddr);
    }
}
/*
		GET
		/day14
		/requestDemo1
		name=zhangsan
		/day14/requestDemo1
		http://localhost:8080/day14/requestDemo1
		HTTP/1.1
		0:0:0:0:0:0:0:1
*/

2. 获取请求头数据

方法：
- (*)String getHeader(String name):通过请求头的名称获取请求头的值
- Enumeration<String> getHeaderNames():获取所有的请求头名称

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.Enumeration;

@WebServlet("/requestDemo2")
public class RequestDemo2 extends HttpServlet {
    
    
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    
    

    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    
    
        //演示获取请求头数据
        
        //1.获取所有请求头名称
        Enumeration<String> headerNames = request.getHeaderNames();
        //2.遍历
        while(headerNames.hasMoreElements()){
    
    
            String name = headerNames.nextElement();
            //根据名称获取请求头的值
            String value = request.getHeader(name);
            System.out.println(name+"---"+value);
        }

    }
}

package com.example.request;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.Enumeration;

@WebServlet("/requestDemo3")
public class RequestDemo3 extends HttpServlet {
    
    
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    
    
    }
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    
    
        //演示获取请求头数据:user-agent

        String agent = request.getHeader("user-agent");
        //判断agent的浏览器版本
        if(agent.contains("Chrome")){
    
    
            //谷歌
            System.out.println("谷歌来了...");
        }else if(agent.contains("Firefox")){
    
    
            //火狐
            System.out.println("火狐来了...");
        }
    }
}

import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

@WebServlet("/requestDemo4")
public class RequestDemo4 extends HttpServlet {
    
    
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    
    

    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    
    
        //演示获取请求头数据:referer

        String referer = request.getHeader("referer");
        System.out.println(referer);//http://localhost/day14/login.html

        //防盗链
        if(referer != null ){
    
    
            if(referer.contains("/day14")){
    
    
                //正常访问
               // System.out.println("播放电影....");
                response.setContentType("text/html;charset=utf-8");
                response.getWriter().write("播放电影....");
            }else{
    
    
                //盗链
                //System.out.println("想看电影吗？来优酷吧...");
                response.setContentType("text/html;charset=utf-8");
                response.getWriter().write("想看电影吗？来优酷吧...");
            }
        }

    }
}

3. 获取请求体数据:

请求体：只有POST请求方式，才有请求体，在请求体中封装了POST请求的请求参数
步骤：
1. 获取流对象
  BufferedReader getReader()：获取字符输入流，只能操作字符数据
  ServletInputStream getInputStream()：获取字节输入流，可以操作所有类型数据
2. 再从流对象中拿数据

3.1.3.2 其他功能：

1. 获取请求参数通用方式：不论get还是post请求方式都可以使用下列方法来获取请求参数

String getParameter(String name):根据参数名称获取参数值 username=zs&password=123
String[] getParameterValues(String name):根据参数名称获取参数值的数组 hobby=xx&hobby=game
Enumeration<String> getParameterNames():获取所有请求的参数名称
Map<String,String[]> getParameterMap():获取所有参数的map集合

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.BufferedReader;
import java.io.IOException;
import java.util.Enumeration;
import java.util.Map;
import java.util.Set;

@WebServlet("/requestDemo6")
public class RequestDemo6 extends HttpServlet {
    
    
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    
    
        //post 获取请求参数

        //根据参数名称获取参数值
        String username = request.getParameter("username");

        //根据参数名称获取参数值的数组
        String[] hobbies = request.getParameterValues("hobby");
        /*for (String hobby : hobbies) {
            System.out.println(hobby);
        }*/

        //获取所有请求的参数名称

        Enumeration<String> parameterNames = request.getParameterNames();
        /*while(parameterNames.hasMoreElements()){
            String name = parameterNames.nextElement();
            System.out.println(name);
            String value = request.getParameter(name);
            System.out.println(value);
            System.out.println("----------------");
        }*/

        // 获取所有参数的map集合
        Map<String, String[]> parameterMap = request.getParameterMap();
        //遍历
        Set<String> keyset = parameterMap.keySet();
        for (String name : keyset) {
    
    

            //获取键获取值
            String[] values = parameterMap.get(name);
            System.out.println(name);
            for (String value : values) {
    
    
                System.out.println(value);
            }

            System.out.println("-----------------");
        }


    }
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    
    
        this.doPost(request,response);
    }
}

中文乱码问题：
- get方式：tomcat 8 已经将get方式乱码问题解决了
- post方式：会乱码
  - 解决：在获取参数前，设置request的编码request.setCharacterEncoding("utf-8");

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

@WebServlet("/requestDemo7")
public class RequestDemo7 extends HttpServlet {
    
    
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    
    
        //1.设置流的编码
        request.setCharacterEncoding("utf-8");

        //获取请求参数username
        String username = request.getParameter("username");

        System.out.println(username);
    }

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

        this.doPost(request,response);
    }
}

在这里插入图片描述

2. 请求转发：一种在服务器内部的资源跳转方式

步骤：
1. 通过request对象获取请求转发器对象：RequestDispatcher getRequestDispatcher(String path)
2. 使用RequestDispatcher对象来进行转发
  forward(ServletRequest request, ServletResponse response)
特点：
1. 浏览器地址栏路径不发生变化
2. 只能转发到当前服务器内部资源中。
3. 转发是一次请求

import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

@WebServlet("/requestDemo8")
public class RequestDemo8 extends HttpServlet {
    
    
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    
    
        System.out.println("demo8888被访问了。。。");
        //转发到demo9资源
/*
        RequestDispatcher requestDispatcher = request.getRequestDispatcher("/requestDemo9");
        requestDispatcher.forward(request,response);
        */

        //存储数据到request域中
        request.setAttribute("msg","hello");

        request.getRequestDispatcher("/requestDemo9").forward(request,response);
        //request.getRequestDispatcher("https://www.baidu.com").forward(request,response);

    }

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

        this.doPost(request,response);
    }
}

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

@WebServlet("/requestDemo9")
public class RequestDemo9 extends HttpServlet {
    
    
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    
    

        //获取数据
        Object msg = request.getAttribute("msg");
        System.out.println(msg);

        System.out.println("demo9999被访问了。。。");

    }

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

        this.doPost(request,response);
    }
}

3. 共享数据：

域对象：一个有作用范围的对象，可以在范围内共享数据
request域：代表一次请求的范围，一般用于请求转发的多个资源中共享数据
方法：
1. void setAttribute(String name,Object obj):存储数据
2. Object getAttitude(String name):通过键获取值
3. void removeAttribute(String name):通过键移除键值对

4. 获取ServletContext：

ServletContext getServletContext()

import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

@WebServlet("/requestDemo10")
public class RequestDemo10 extends HttpServlet {
    
    
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    
    


        ServletContext servletContext = request.getServletContext();

        System.out.println(servletContext);

    }

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

        this.doPost(request,response);
    }
}

案例：用户登录

用户登录案例需求：
1. 编写login.html登录页面
  username & password 两个输入框
2. 使用Druid数据库连接池技术,操作mysql，day14数据库中user表
3. 使用JdbcTemplate技术封装JDBC
4. 登录成功跳转到SuccessServlet展示：登录成功！用户名,欢迎您
5. 登录失败跳转到FailServlet展示：登录失败，用户名或密码错误
分析
开发步骤

创建项目，导入html页面，配置文件，jar包
创建数据库环境

CREATE DATABASE day14;
			USE day14;
			CREATE TABLE USER(
				id INT PRIMARY KEY AUTO_INCREMENT,
				username VARCHAR(32) UNIQUE NOT NULL,
				PASSWORD VARCHAR(32) NOT NULL
			);

创建包cn.example.domain,创建类User

/**
 * 用户的实体类
 */
public class User {
    
    

    private int id;
    private String username;
    private String password;


    public int getId() {
    
    
        return id;
    }

    public void setId(int id) {
    
    
        this.id = id;
    }

    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;
    }

    @Override
    public String toString() {
    
    
        return "User{" +
                "id=" + id +
                ", username='" + username + '\'' +
                ", password='" + password + '\'' +
                '}';
    }
}

创建包cn.example.util,编写工具类JDBCUtils

import com.alibaba.druid.pool.DruidDataSourceFactory;

import javax.sql.DataSource;
import javax.xml.crypto.Data;
import java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.Properties;

/**
 * JDBC工具类 使用Durid连接池
 */
public class JDBCUtils {
    
    

    private static DataSource ds ;

    static {
    
    

        try {
    
    
            //1.加载配置文件
            Properties pro = new Properties();
            //使用ClassLoader加载配置文件，获取字节输入流
            InputStream is = JDBCUtils.class.getClassLoader().getResourceAsStream("druid.properties");
            pro.load(is);

            //2.初始化连接池对象
            ds = DruidDataSourceFactory.createDataSource(pro);

        } catch (IOException e) {
    
    
            e.printStackTrace();
        } catch (Exception e) {
    
    
            e.printStackTrace();
        }
    }

    /**
     * 获取连接池对象
     */
    public static DataSource getDataSource(){
    
    
        return ds;
    }


    /**
     * 获取连接Connection对象
     */
    public static Connection getConnection() throws SQLException {
    
    
        return  ds.getConnection();
    }
}

创建包cn.example.dao,创建类UserDao,提供login方法

import cn.example.domain.User;
import cn.example.util.JDBCUtils;
import org.springframework.dao.DataAccessException;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;

/**
 * 操作数据库中User表的类
 */
public class UserDao {
    
    

    //声明JDBCTemplate对象共用
    private JdbcTemplate template = new JdbcTemplate(JDBCUtils.getDataSource());

    /**
     * 登录方法
     * @param loginUser 只有用户名和密码
     * @return user包含用户全部数据,没有查询到，返回null
     */
    public User login(User loginUser){
    
    
        try {
    
    
            //1.编写sql
            String sql = "select * from user where username = ? and password = ?";
            //2.调用query方法
            User user = template.queryForObject(sql,
                    new BeanPropertyRowMapper<User>(User.class),
                    loginUser.getUsername(), loginUser.getPassword());


            return user;
        } catch (DataAccessException e) {
    
    
            e.printStackTrace();//记录日志
            return null;
        }
    }
}

编写cn.example.web.servlet.LoginServlet类

import cn.example.dao.UserDao;
import cn.example.domain.User;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;


@WebServlet("/loginServlet")
public class LoginServlet extends HttpServlet {
    
    


    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    
    
        //1.设置编码
        req.setCharacterEncoding("utf-8");
        //2.获取请求参数
        String username = req.getParameter("username");
        String password = req.getParameter("password");
        //3.封装user对象
        User loginUser = new User();
        loginUser.setUsername(username);
        loginUser.setPassword(password);

        //4.调用UserDao的login方法
        UserDao dao = new UserDao();
        User user = dao.login(loginUser);

        //5.判断user
        if(user == null){
    
    
            //登录失败
            req.getRequestDispatcher("/failServlet").forward(req,resp);
        }else{
    
    
            //登录成功
            //存储数据
            req.setAttribute("user",user);
            //转发
            req.getRequestDispatcher("/successServlet").forward(req,resp);
        }

    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    
    
        this.doGet(req,resp);
    }
}

编写FailServlet和SuccessServlet类

@WebServlet("/successServlet")
public class SuccessServlet extends HttpServlet {
    
    
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    
    
        //获取request域中共享的user对象
        User user = (User) request.getAttribute("user");

        if(user != null){
    
    
            //给页面写一句话

            //设置编码
            response.setContentType("text/html;charset=utf-8");
            //输出
            response.getWriter().write("登录成功！"+user.getUsername()+",欢迎您");
        }


    }		


@WebServlet("/failServlet")
public class FailServlet extends HttpServlet {
    
    
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    
    
        //给页面写一句话

        //设置编码
        response.setContentType("text/html;charset=utf-8");
        //输出
        response.getWriter().write("登录失败，用户名或密码错误");

    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    
    
        this.doPost(request,response);
    }
}

login.html中form表单的action路径的写法
- 虚拟目录+Servlet的资源路径
BeanUtils工具类，简化数据封装
- 用于封装JavaBean的
1. JavaBean：标准的Java类
  1. 要求：
    1. 类必须被public修饰
    2. 必须提供空参的构造器
    3. 成员变量必须使用private修饰
    4. 提供公共setter和getter方法
  2. 功能：封装数据
2. 概念：
  成员变量：
  属性：setter和getter方法截取后的产物
  例如：getUsername() --> Username--> username
3. 方法：
  1. setProperty()
  2. getProperty()
  3. populate(Object obj , Map map):将map集合的键值对信息，封装到对应的JavaBean对象中

package com.example.web.servlet;
import com.example.damain.User;
import com.example.dao.UserDao;
import org.apache.commons.beanutils.BeanUtils;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.util.Map;

@WebServlet("/loginServlet")
public class LoginServlet extends HttpServlet {
    
    
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    
    

        req.setCharacterEncoding("utf-8");
        //2.获取所有请求参数
        Map<String, String[]> map = req.getParameterMap();
        //3.创建User对象
        User loginUser = new User();
        //3.2 使用BeanUtils封装
        try {
    
    
            BeanUtils.populate(loginUser,map);
        } catch (IllegalAccessException e) {
    
    
            e.printStackTrace();
        } catch (InvocationTargetException e) {
    
    
            e.printStackTrace();
        }

        UserDao dao = new UserDao();
        User user = dao.login(loginUser);

        if(user == null){
    
    
            req.getRequestDispatcher("/failServlet").forward(req,resp);
        }else{
    
    
            req.setAttribute("user",user);
            req.getRequestDispatcher("/successServlet").forward(req,resp);
        }
    }

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    
    
        super.doPost(req, resp);
    }
}

public class BeanUtilsTest {
    
    

    @Test
    public void test(){
    
    

        User user = new User();
        try {
    
    
            BeanUtils.setProperty(user,"hehe","male");
            System.out.println(user);

            String gender = BeanUtils.getProperty(user, "hehe");
            System.out.println(gender);
        } catch (IllegalAccessException e) {
    
    
            e.printStackTrace();
        } catch (InvocationTargetException e) {
    
    
            e.printStackTrace();
        } catch (NoSuchMethodException e) {
    
    
            e.printStackTrace();
        }
    }
}

HTTP&Request -＞（个人学习记录笔记）

文章目录

HTTP：

1. 概念：Hyper Text Transfer Protocol 超文本传输协议

2. 请求消息数据格式

2.1 请求行

2.2 请求头：客户端浏览器告诉服务器一些信息

2.3 请求空行

2.4 请求体(正文)：

3. 响应消息数据格式

3.1 Request：

3.1.1 request对象和response对象的原理

3.1.2 request对象继承体系结构：

3.1.3 request功能：

3.1.3.1 获取请求消息数据

1. 获取请求行数据

2. 获取请求头数据

3. 获取请求体数据:

3.1.3.2 其他功能：

1. 获取请求参数通用方式：不论get还是post请求方式都可以使用下列方法来获取请求参数

2. 请求转发：一种在服务器内部的资源跳转方式

3. 共享数据：

4. 获取ServletContext：

案例：用户登录

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