Request笔记 - 爱码网

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

Request笔记

2 通过 request 获得【请求行】

1 通过抓包工具抓取 Http 请求

Request笔记

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。

2 通过 request 获得请求行

Request笔记

html部分代码：

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
    <form action="/WEBTest13/line" method="get">
        <input type="text" name="username"><br> <input
            type="password" name="password"><br> <input
            type="submit" value="提交"><br>
    </form>
</body>
</html>

servlet代码：

package p5.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 LineServlet extends HttpServlet {

    public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //首先解决respone中文乱码
        response.setContentType("text/html;charset=UTF-8");
        
        // 1 获取客户端的请求方法
        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();
        StringBuffer requestURL = request.getRequestURL();
        System.out.println("requestURI:"+requestURI);
        System.out.println("requestURL:"+requestURL);
        
        // 3 获取web应用的名称
        String contextPath = request.getContextPath();
        System.out.println("contextPath:"+contextPath);
        
        // 4 获取地址后的参数字符串
        String queryString = request.getQueryString();
        System.out.println("queryString:"+queryString);

        // 5 获得请求的协议版本
        String protocol = request.getProtocol();
        System.out.println("protocol:"+protocol);
    }

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

}

运行结果：

Request笔记

3 Resquest 获得客户机的信息

Request笔记

4 通过 request 获得【请求头】

Request笔记

servlet代码：

package header;

import java.io.IOException;
import java.util.Enumeration;

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

public class HeaderServlet extends HttpServlet {

    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        
        //1、获得指定的头
        String header = request.getHeader("User-Agent");
        System.out.println(header);
        //2、获得所有的头的名称
        Enumeration<String> headerNames = request.getHeaderNames();
        while(headerNames.hasMoreElements()){
            String headerName = headerNames.nextElement();
            String headerValue = request.getHeader(headerName);
            System.out.println(headerName+":"+headerValue);
        }
        
    }

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

html代码：

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
    <a href="/WEB15/referer">访问 headerServlet 资源</a>
    <form action="/WEBTest13/line" method="get">
        <input type="text" name="username"><br> <input
            type="password" name="password"><br> <input
            type="submit" value="提交"><br>
    </form>
</body>
</html>

Request笔记

演示做防盗链代码实现

html部分代码：

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
    <a href="/WEB15/referer">奥运会金牌100块</a>
</body>
</html>

servlet代码

package header;

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 RefererServlet extends HttpServlet {

    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        //解决乱码问题
        response.setContentType("text/html;charset=UTF-8");
        
        //对该新闻的来源的进行判断
        String header = request.getHeader("referer");
        if(header!=null&&header.startsWith("http://localhost")){
            //是从我自己的网站跳转过来的 可以看新闻
            response.getWriter().write("中国确实已经拿到100块金牌....");
        }else{
            response.getWriter().write("你是盗链者，可耻！！");
        }
        
        
    }

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

5 通过 request 获得【请求体】

Request笔记

html部分的代码：

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
    <a href="/WEBTest13/referer">访问headerServlet资源</a>
    <form action="/WEBTest13/line" method="get">
        <input type="text" name="username"><br>
        <input type="password" name="password"><br>
        <input type="submit" value="提交"><br>
    </form>
    <hr/>
    <form action="/WEBTest13/content" method="get">
        <input type="text" name="username"><br>
        <input type="password" name="password"><br>
        <input type="checkbox" name="hobby" value="zq">足球
        <input type="checkbox" name="hobby" value="pq">排球
        <input type="checkbox" name="hobby" value="ppq">乒乓球<br>
        <input type="submit" value="提交"><br>
    </form>
</body>
</html>

servlet部分代码：

package cotnet;

import java.io.IOException;
import java.util.Enumeration;
import java.util.Map;

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

public class ContentServlet extends HttpServlet {

    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        
        //1、获得单个表单值
        String username = request.getParameter("username");
        System.out.println(username);
        String password = request.getParameter("password");
        System.out.println(password);
        //2、获得多个表单的值
        String[] hobbys = request.getParameterValues("hobby");
        for(String hobby:hobbys){
            System.out.println(hobby);
        }
        //3、获得所有的请求参数的名称
        Enumeration<String> parameterNames = request.getParameterNames();
        while(parameterNames.hasMoreElements()){
            System.out.println(parameterNames.nextElement());
        }
        System.out.println("------------------");
        //4、获得所有的参数 参数封装到一个Map<String,String[]>
        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("---------------------------");
        }
        
    }
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        doGet(request, response);
    }
}

6 Resquest 域对象和请求转发

1 request 是一个域对象

Request笔记

2 request 完成请求转发

Request笔记

servlet1代码：

package forward;

import java.io.IOException;

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

public class Servlet1 extends HttpServlet {

    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        
        //想request域中存储数据
        request.setAttribute("name", "tom");
        
        
        //servlet1 将请求转发给servlet2
        RequestDispatcher dispatcher = request.getRequestDispatcher("/servlet2");
        //执行转发的方法
        dispatcher.forward(request, response);
        
    }

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

servlet2代码：

package forward;

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 Servlet2 extends HttpServlet {

    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        
        //从request域中取出数据
        Object attribute = request.getAttribute("name");
        
        response.getWriter().write("hello haohao..."+attribute);
    }

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

运行结果：

Request笔记

3 ServletContext 域与 Request 域的生命周期比较？

Request笔记

4转发与重定向的区别？

Request笔记

5 客户端地址与服务器端地址的写法？

Request笔记

7 注册分析

Request笔记

8 注册的基本实现

1 创建user表

CREATE TABLE `user` (
  `uid` varchar(50) NOT NULL,
  `username` varchar(20) DEFAULT NULL,
  `password` varchar(20) DEFAULT NULL,
  `name` varchar(20) DEFAULT NULL,
  `email` varchar(30) DEFAULT NULL,
  `telephone` varchar(20) DEFAULT NULL,
  `birthday` varchar(20) DEFAULT NULL,
  `sex` varchar(10) DEFAULT NULL,
  `state` int(11) DEFAULT NULL,
  `code` varchar(64) DEFAULT NULL,
  PRIMARY KEY (`uid`)
)

2 Servlet代码

package 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 com.ithiema.utils.DataSourceUtils;

public class RegisterServlet extends HttpServlet {

    protected 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);
    }

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

2 User类

package 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 [u
                + email + ", sex=" + sex + ", birthday=" + birthday + "]";
    }
    
    
    
    
    
}

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