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HttpServletrequest 注册和登录、request域对象、web动态shop

summarize

httpServletResponse跟 Request一个是响应一个是请求,获得客户端请求方式用getMethod 得到的是String类型，

response：属于重定向请求、地址栏URL会发生改变、想服务器发送两次请求 response解决中文乱码：response.setContentType("text/html;charset=utf-8");

request：属于请求转发，成对创建，客户端请求一次，地址栏不改变，真正给资源的是Servlet02 。获取请求转发可以直接写转发的路径，无需写项目目录，因服务器内部行为，这也是与重定向的区别

何时用重定向何时用请求转发？看需求，如果从servlet01带数据给servlet02 就用请求转发，若不带数据用重定向或看地址拦：需要地址栏改变用重定向，不需要改变用请求转发

HttpServletRequest

request代表请求，通过该对象，分别获得HTTP请求的请求行、请求头、请求体

1.通过request获得请求行

步骤：

获得客户端请求方式：String getMethod()

获取请求资源：

String getRequestURI()：返回除去host（域名或者ip）部分的路径

StringBuffer getRequestURL()：返回全路径

String getContextPath()：获取web应用名称（项目名）

String getQueryString()：获取get提交url地址后的参数字符串例如：username=zhangsan&password=123

新建个项目 WEB06-在建login.jsp 页面--在建一个Servlet

请求行代码演示

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
    <form action="/WEB06/LineServlet" method="get">
        <input type="text" name="username"><br>
        <input type="password" name="pwd"><br>
        <input type="submit" value="提交">
    </form>
</body>
</html>
------------------------------------
package com.oracle.demo01;
//通过request获得请求行里面的信息
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 {
//        获取请求方式
        String method=request.getMethod();
        System.out.println("请求方式为"+method);
//        获取请求 URI
        String URI=request.getRequestURI();
        System.out.println("URI为"+URI);
//        获取获取 URL
        StringBuffer URL=request.getRequestURL();
        System.out.println("URL为"+URL);
//        获取WEB应用名称
        String name=request.getContextPath();
        System.out.println("WEB应用名称为"+name);
//        获取get请求后url后的字符串
        String query=request.getQueryString();
        System.out.println("get请求参数为："+query);
//        获取客户端的IP地址
        String ip=request.getRemoteAddr();
        System.out.println("ip地址为: "+ip);
    }

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

以上代码的方法就是请求行里获取的信息

URI和URL的区别

URI：uniform resource identifier，统一资源标识符，用来唯一的标识一个资源。

URL：uniform resource locator，具体的URI，可以用来标识一个资源，指明了如何locate这个资源

总结：URL是一种具体的URI，它不仅唯一标识资源，而且还提供了定位该资源的信息。URI是抽象概念，可以是绝对，也可以是相对，而URL则必须提供足够的信息来定位，so，是绝对的

request获得请求头

referer头的作用做防盗链代码:

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<!-- 防盗链 -->
    <a href="/WEB06/RefereServlet">我就是我</a>
</body>
</html>
--------------------------------
新建个Servlet让jsp指向这个Servlet
package com.oracle.demo01;
//通过request的 防盗链
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 RefereServlet extends HttpServlet {
    public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//        获取refere头
        String refere=request.getHeader("Referer");
        String content=null;
//        判断refere地址以什么开头  必须加上http://
        if(refere.startsWith("http://localhost:8080")){
            content="真的离婚了!";
        }else{
            content="你是小偷";
        }
//        解决response的中文乱码
        response.setContentType("text/html;charset=utf-8");
        response.getWriter().write(content);
    }

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

请求头的作用就是，可做防盗链，当在网页打开一个链接，为了防止打开的这链接会被盗链，可以给地址设置一个地址的开头：看图得知

当我们点开这个链接时，会进入另一个地址，判断这个刚要打开的地址是以谁开头，用.startsWith后面必须+ http://localhost:8080，如果是它开头则是真的，如果不是，则显示你是小偷

通过request获得请求体

以上面参数为例，通过一下方法获得请求参数：

String getParameter(String name) ---获得单个值

String[] getParameterValues(Stringname) -----获得多个值

Enumeration getParameterNames()

代码:

------------->通过getparametermap获取所有参数，得到map集合

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
    <form action="/WEB06/BodyServlet" method="post">
        <input type="text" name="username">
        <input type="radio" name="sex" value="woman">女
        <input type="radio" name="sex" value="man">男
        <br>
        <input type="checkbox" name="hobby" value="pqq">
        乒乓球
        <input type="checkbox" name="hobby" value="pq">
        皮球
        <input type="checkbox" name="hobby" value="wq">
        网球
        <br>
        <input type="submit" value="提交">
    </form>
</body>
</html>
--------------------------------------------
package com.oracle.demo01;
//request获得请求体的方法获得参数
import java.io.IOException;
import java.util.Map;
import java.util.Set;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.swing.plaf.synth.SynthSeparatorUI;

public class BodyServlet extends HttpServlet {

    public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//        post解决中文乱码
        request.setCharacterEncoding("utf-8");//在获取参数前修改就是把整个请求体里的乱码
//        获取请求参数
//        1.获取单个值的参数  获取单个的值就parameter方法
        String name=request.getParameter("username");//name属性名
//        get方式解决乱码: 必须每一个带中文的都来一遍   表单提交：正常人不用get
//        name=new String(name.getBytes("ISO-8859-1"),"UTF-8");
        String sex=request.getParameter("sex");//获得单选框的值
        System.out.println(name+"..."+sex);//打印上面俩名字
//        2.获取多个值
        String[] hobbys=request.getParameterValues("hobby");
        System.out.println(hobbys);//打印数组
//        3.获取所有请求参数Map
        Map<String,String[]> map=request.getParameterMap();
//        遍历
        Set<String> set=map.keySet();
        for(String str:set){
            String[] value=map.get(str);
            for(String v:value){
                System.out.println(str+"..."+v);
            }
        }
    }

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

解决post提交中文乱码：

解决中文乱码:在获取参数之前+一行代码

request.setCharacterEncoding("utf-8"); 注意：在获取参数以前设置

在最顶上设置中文乱码后，解决整个请求体里所有参数都可接收中文看加上代码后的效果显示图

解决get提交乱码：parameter = new String(parameter.getbytes("iso8859-1"),"utf-8");

一般人不会用这个麻烦

request其他功能

1.request 是一个域对象----存储数据的区域对象 Servlet一共三个域对象，功能一样，作用域范围不一样。

方法：

setAttribute(String name, Object o) 存值

getAttribute(String name) 取值

removeAttribute(String name)

注意：request域的作用范围：一次请求中

request 请求转发原理图：

重定向：特点：1客户端请求两次 2地址栏改变举例原理：客户端向servlet01借钱，servlet01回复客户端没钱，并告诉客户端Servlet 02有钱，然后servlet又向02发送请求借钱

请求转发：跟重定向功能一样：客户端发送一次请求，地址栏不变。举例原理：客户端向servlet01请求借钱，servlet01没钱，但他又向servlet02借钱给客户端，实际上是servlet02借给客户端，这种行为是服务器内部行为，servlet01请求servlet02，客户端只发送一次

(1)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)

package com.oracle.demo02;
//request完成请求转发
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 Servlet01 extends HttpServlet {

    public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//        请求转发                                        获得转发器 forward方法
        request.getRequestDispatcher("/Servlet02").forward(request, response);//因为是服务器内部行为，无需写/WEB目录，so：是重定向区别
        
    }

    public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doGet(request, response);
    }
}
------------------------------------
package com.oracle.demo02;

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 Servlet02 extends HttpServlet {

    public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//        从request域中取值 get是取值
        String name=(String)request.getAttribute("name");
//        解决resonance中文乱码
        response.setContentType("text/html;charset=utf-8");
        response.getWriter().write("hello sensen..."+name);
    }

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

做一个注册web页面

创建 Shop动态项目

导入3个包

创建三层包

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 {
     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=" 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
                <form class="form-horizontal" style="margin-top: 5px;" action="/Shop/RegisterServlet" 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"
                                placeholder="请输入用户名" name="username">
                        </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"
                                placeholder="请输入密码" name="password">
                        </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"
                                placeholder="Email" name="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"
                                placeholder="请输入姓名" name="name">
                        </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="sex1" value="male">
                                男
                            </label> 
                            <label class="radio-inline"> 
                            <input type="radio" name="sex" id="sex2" 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" name="checkCode">

                        </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;  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>

RegisterServlet

package com.oracle.web;
RegisterServlet
import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
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 com.oracle.domain.Users;
import com.oracle.service.UserService;

public class RegisterServlet extends HttpServlet {
    private UserService userService=new UserService();
    public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        
//        解决request的中文乱码 
        request.setCharacterEncoding("UTF-8");
//        获取所有请求参数的map集合
        Map<String,String[]> map=request.getParameterMap();
//        创建Users对象
        Users users=new Users();
//        用BeanUtiles中的方法将map集合中的参数封装到Users对象中 
//        原理：根据map中的key跟user对象中的属性名一一映射
        try {
            BeanUtils.populate(users,map);
        } catch (IllegalAccessException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (InvocationTargetException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
//        封装uid 唯一一个随机产生36位不重复字符串
        users.setUid(UUID.randomUUID().toString());
//        调用Service方法
        userService.register(users);
//        认为注册成功,重定向登录页面
        response.sendRedirect(request.getContextPath()+"/login.jsp");
    }

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

JDBCUtils

package com.oracle.tools;

import java.io.FileInputStream;
import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties;

//JDBC工具类
public class JDBCUtils {
    //获取连接对象的方法
    public static Connection getConn(){
        Connection conn=null;    
        Properties pro=new Properties();
        try {
            //1.注册驱动
            Class.forName("com.mysql.jdbc.Driver");
            //2.获取链接对象
            String url="jdbc:mysql://localhost:3306/store_v1.0?useUnicode=true&characterEncoding=UTF-8";//0603后面插这句=红娘
            String user="root";
            String password="123456";
            conn=DriverManager.getConnection(url,user,password);
        } catch (ClassNotFoundException | SQLException e) {            
            e.printStackTrace();
        }
        return conn;            
    }
    //释放资源1
    public static void close(Connection conn,Statement sta){
        if(sta!=null){
            try {
                sta.close();
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
        if(conn!=null){
            try {
                conn.close();
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }        
    }
    //释放资源2
    public static void close(Connection conn,Statement sta,ResultSet rs){
        if(rs!=null){
            try {
            rs.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        if(sta!=null){
            try {
                sta.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        if(conn!=null){
            try {
                conn.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }
}

Users

package com.oracle.domain;

public class Users {
    private String uid;
    private String username;
    private String password;
    private String name;
    private String email;
    private String telephone;
    private String birthday;
    private String sex;
    private int state;
    private String code;
    
    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 getTelephone() {
        return telephone;
    }

    public void setTelephone(String telephone) {
        this.telephone = telephone;
    }

    public String getBirthday() {
        return birthday;
    }

    public void setBirthday(String birthday) {
        this.birthday = birthday;
    }

    public String getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }

    public int getState() {
        return state;
    }

    public void setState(int state) {
        this.state = state;
    }

    public String getCode() {
        return code;
    }

    public void setCode(String code) {
        this.code = code;
    }

    @Override
    public String toString() {
        return "Users [uid=" + uid + ", username=" + username + ", password=" + password + ", name=" + name + ", email="
                + email + ", telephone=" + telephone + ", birthday=" + birthday + ", sex=" + sex + ", state=" + state
                + ", code=" + code + "]";
    }
    
}

创建 UsersDao

package com.oracle.dao;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.SQLException;

import com.oracle.domain.Users;
import com.oracle.tools.JDBCUtils;

public class UsersDao {
//    登录  需要导包
    public void register(Users users) throws SQLException{
    
//        获得连接对象
        Connection conn=JDBCUtils.getConn();
//        获得sql语句
//        String sql="insert into users(uid,username,password,email,name,sex,birthday) values(?,?,?,?,?,?,?)";
        String sql="insert into users(uid,username,"
                + "password,email,name,sex,birthday) "
                + "values(?,?,?,?,?,?,?)";

        PreparedStatement pst=conn.prepareStatement(sql);
        pst.setString(1,users.getUid());
        pst.setString(2,users.getUsername());
        pst.setString(3,users.getPassword());
        pst.setString(4,users.getEmail());
        pst.setString(5,users.getName());
        pst.setString(6,users.getSex());
        pst.setString(7,users.getBirthday());
//        执行sql
        pst.executeUpdate();
//        释放资源
        JDBCUtils.close(conn,pst);
    }
}

创建 UserService

package com.oracle.service;

import java.sql.SQLException;

import com.oracle.dao.UsersDao;
import com.oracle.domain.Users;

public class UserService {
    private UsersDao usersDao=new UsersDao();
//    注册
    public void register(Users users){
        try {
            usersDao.register(users);
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
//    登录
    public int login(String username,String password){
//        处理异常
        int count=0;
        try {
            count=usersDao.login(username, password);
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return count;
    }
}

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原文地址：https://www.cnblogs.com/zs0322/p/11125656.html