request 和 response

request

主要使用的是HttpServletRequest 在实际的开发中我们使用的servlet都是httpservlet

请求一共分为三步
1. 请求行
  1. •String getMethod()：获取请求方式： GET
    
    •String getContextPath()：获取虚拟目录(项目访问路径)： /request-demo
    
    •StringBuffer getRequestURL(): 获取URL(统一资源定位符)：http://localhost:8080/request-demo/req1
    
    •String getRequestURI()：获取URI(统一资源标识符)： /request-demo/req1
    
    •String getQueryString()：获取请求参数（GET方式）： username=zhangsan&password=123
2. 请求头
  1. •String getHeader(String name)：根据请求头名称，获取值
3. 请求体（只有在post请求中才会有请求体的存在，在请求体中存在的是请求的数据）
  
  •ServletInputStream getInputStream()：获取字节输入流
  
  •BufferedReader getReader()：获取字符输入流
获取统一的请求参数的方法(目的是为了使doget和dopost都调用的是同一个方法这样的话减少代码的书写)

•Map<String, String[ ]> getParameterMap()：获取所有参数Map集合

•String[ ] getParameterValues(String name) ：根据名称获取参数值（数组）

•String getParameter(String name)：根据名称获取参数值（单个值）
解决中文乱码问题
post方式解决中文乱码问题
```
req.setCharacterEncoding(“UTF-8");
```
通用的方式解决中文乱码问题(其中的username是要获取的具体的值)

new String(username.getBytes("ISO-8859-1"),"UTF-8");

request请求转发

req.getRequestDispatcher("资源B路径").forward(req,resp);

response

重定向

resp.setStatus(302);
resp.setHeader(“location”,“资源B的路径");
简化的方法：resp.sendRedirect("资源B的路径");

设置字符数据的响应体

@WebServlet("/Servletresponse3")
public class Servletresponse3 extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    this.doGet(request,response);
    }

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

        PrintWriter writer = response.getWriter();
        writer.write("aaaaa");
        流不需要关闭
        如果要使用中文的话会出现乱码的情况
    }
}

案例：使用servlet来实现用户的注册和登录

首先是登录和注册页面的准备

登录页面
<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <title>login</title>
    <link href="css/login.css" rel="stylesheet">
</head>

<body>
<div id="loginDiv">
    <form action="/C/loginServlet" method="post" id="form">
        <h1 id="loginMsg">LOGIN IN</h1>
        <p>Username:<input id="username" name="username" type="text"></p>

        <p>Password:<input id="password" name="password" type="password"></p>

        <div id="subDiv">
            <input type="submit" class="button" value="login up">
            <input type="reset" class="button" value="reset">&nbsp;&nbsp;&nbsp;
            <a href="register.html">没有账号？点击注册</a>
        </div>
    </form>
</div>

</body>
</html>

css样式
* {
    margin: 0;
    padding: 0;
}

html {
    height: 100%;
    width: 100%;
    overflow: hidden;
    margin: 0;
    padding: 0;
    background: url(../imgs/Desert.jpg) no-repeat 0px 0px;
    background-repeat: no-repeat;
    background-size: 100% 100%;
    -moz-background-size: 100% 100%;
}

body {
    display: flex;
    align-items: center;
    justify-content: center;
    height: 100%;
}

#loginDiv {
    width: 37%;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 300px;
    background-color: rgba(75, 81, 95, 0.3);
    box-shadow: 7px 7px 17px rgba(52, 56, 66, 0.5);
    border-radius: 5px;
}

#name_trip {
    margin-left: 50px;
    color: red;
}

p {
    margin-top: 30px;
    margin-left: 20px;
    color: azure;
}

input {
    margin-left: 15px;
    border-radius: 5px;
    border-style: hidden;
    height: 30px;
    width: 140px;
    background-color: rgba(216, 191, 216, 0.5);
    outline: none;
    color: #f0edf3;
    padding-left: 10px;
}
#username{
    width: 200px;
}
#password{
    width: 202px;
}
.button {
    border-color: cornsilk;
    background-color: rgba(100, 149, 237, .7);
    color: aliceblue;
    border-style: hidden;
    border-radius: 5px;
    width: 100px;
    height: 31px;
    font-size: 16px;
}

#subDiv {
    text-align: center;
    margin-top: 30px;
}
#loginMsg{
    text-align: center;color: aliceblue;
}

注册页面
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>欢迎注册</title>
    <link href="css/register.css" rel="stylesheet">
</head>
<body>

<div class="form-div">
    <div class="reg-content">
        <h1>欢迎注册</h1>
        <span>已有帐号？</span> <a href="login.html">登录</a>
    </div>
    <form id="reg-form" action="/C/registerServlet" method="post">

        <table>

            <tr>
                <td>用户名</td>
                <td class="inputs">
                    <input name="username" type="text" id="username">
                    <br>
                    <span id="username_err" class="err_msg" style="display: none">用户名不太受欢迎</span>
                </td>

            </tr>

            <tr>
                <td>密码</td>
                <td class="inputs">
                    <input name="password" type="password" id="password">
                    <br>
                    <span id="password_err" class="err_msg" style="display: none">密码格式有误</span>
                </td>
            </tr>


        </table>

        <div class="buttons">
            <input value="注 册" type="submit" id="reg_btn">
        </div>
        <br class="clear">
    </form>

</div>
</body>
</html>

css样式
* {
    margin: 0;
    padding: 0;
    list-style-type: none;
}
.reg-content{
    padding: 30px;
    margin: 3px;
}
a, img {
    border: 0;
}

body {
    background-image: url("../imgs/reg_bg_min.jpg") ;
    text-align: center;
}

table {
    border-collapse: collapse;
    border-spacing: 0;
}

td, th {
    padding: 0;
    height: 90px;

}
.inputs{
    vertical-align: top;
}

.clear {
    clear: both;
}

.clear:before, .clear:after {
    content: "";
    display: table;
}

.clear:after {
    clear: both;
}

.form-div {
    background-color: rgba(255, 255, 255, 0.27);
    border-radius: 10px;
    border: 1px solid #aaa;
    width: 424px;
    margin-top: 150px;
    margin-left:1050px;
    padding: 30px 0 20px 0px;
    font-size: 16px;
    box-shadow: inset 0px 0px 10px rgba(255, 255, 255, 0.5), 0px 0px 15px rgba(75, 75, 75, 0.3);
    text-align: left;
}

.form-div input[type="text"], .form-div input[type="password"], .form-div input[type="email"] {
    width: 268px;
    margin: 10px;
    line-height: 20px;
    font-size: 16px;
}

.form-div input[type="checkbox"] {
    margin: 20px 0 20px 10px;
}

.form-div input[type="button"], .form-div input[type="submit"] {
    margin: 10px 20px 0 0;
}

.form-div table {
    margin: 0 auto;
    text-align: right;
    color: rgba(64, 64, 64, 1.00);
}

.form-div table img {
    vertical-align: middle;
    margin: 0 0 5px 0;
}

.footer {
    color: rgba(64, 64, 64, 1.00);
    font-size: 12px;
    margin-top: 30px;
}

.form-div .buttons {
    float: right;
}

input[type="text"], input[type="password"], input[type="email"] {
    border-radius: 8px;
    box-shadow: inset 0 2px 5px #eee;
    padding: 10px;
    border: 1px solid #D4D4D4;
    color: #333333;
    margin-top: 5px;
}

input[type="text"]:focus, input[type="password"]:focus, input[type="email"]:focus {
    border: 1px solid #50afeb;
    outline: none;
}

input[type="button"], input[type="submit"] {
    padding: 7px 15px;
    background-color: #3c6db0;
    text-align: center;
    border-radius: 5px;
    overflow: hidden;
    min-width: 80px;
    border: none;
    color: #FFF;
    box-shadow: 1px 1px 1px rgba(75, 75, 75, 0.3);
}

input[type="button"]:hover, input[type="submit"]:hover {
    background-color: #5a88c8;
}

input[type="button"]:active, input[type="submit"]:active {
    background-color: #5a88c8;
}
.err_msg{
    color: red;
    padding-right: 170px;
}
#password_err,#tel_err{
    padding-right: 195px;
}

#reg_btn{
    margin-right:50px; width: 285px; height: 45px; margin-top:20px;
}

Mybatis的xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    <!--起别名-->
    <typeAliases>
        <package name="com.itheima.pojo"/>
    </typeAliases>

    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"/>
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql:///db1?useSSL=false&amp;useServerPrepStmts=true"/>
                <property name="username" value="root"/>
                <property name="password" value="1234"/>
            </dataSource>
        </environment>
    </environments>
    <mappers>
        <!--扫描mapper-->
        <package name="com.itheima.mapper"/>
    </mappers>
</configuration>

用于查询的mapper接口

package com.itheima.mapper;

import com.itheima.pojo.User;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Param;
import org.apache.ibatis.annotations.Select;

public interface UserMapper {
    /*根据用户名来登录的*/
    @Select("select * from tb_user where username=#{username} and password = #{password}")

    User select(@Param("username") String username, @Param("password") String password);



    @Select("select * from tb_user where username=#{username}")
    User selectByUsername(String username);


    @Insert("insert into tb_user values(null,#{username},#{password})")
    void add(User user);

mapper的映射配置文件

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.itheima.mapper.UserMapper">

</mapper>

获取sqlsession的工具类

package com.itheima.util;

import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;

import java.io.IOException;
import java.io.InputStream;

public class SqlSessionFactoryUtils {
    private static SqlSessionFactory sqlSessionFactory;

    /*静态代码块会随着类的加载而创建而且只会创建一次*/
    static {
        try {
            String resource = "mybatis-config.xml";
            InputStream inputStream = Resources.getResourceAsStream(resource);
            sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    public static SqlSessionFactory getSqlSessionFactory()
    {
        return sqlSessionFactory;

    }
}

登录页面的servlet

package com.itheima.response;

import com.itheima.mapper.UserMapper;
import com.itheima.pojo.User;
import com.itheima.util.SqlSessionFactoryUtils;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;

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.io.InputStream;
import java.io.PrintWriter;

@WebServlet( "/loginServlet")
public class loginServlet extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        this.doGet(request,response);
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String username = request.getParameter("username");
        String password = request.getParameter("password");
        /*调用mybatis来查询数据*/
        SqlSessionFactory sqlSessionFactory = SqlSessionFactoryUtils.getSqlSessionFactory();

        SqlSession sqlSession = sqlSessionFactory.openSession();
        UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
        User user = userMapper.select(username, password);
        sqlSession.close();

        /*获取对应的字符输出流并设置contentType*/
        response.setContentType("text/html;charset=utf-8");
        PrintWriter writer = response.getWriter();

        /*判断是否为null*/
        if (user != null) {
        writer.write("登录成功");

        }
        else {
            writer.write("登录失败");

        }



    }
}

注册页面的servlet

package com.itheima.response;

import com.itheima.mapper.UserMapper;
import com.itheima.pojo.User;
import com.itheima.util.SqlSessionFactoryUtils;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;

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.io.InputStream;

@WebServlet("/registerServlet")
public class registerServlet extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        this.doGet(request,response);
    }

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

        String username = request.getParameter("username");
        String password = request.getParameter("password");
        /* 对用户对象完成封装*/
        User user = new User();
        user.setUsername(username);
        user.setPassword(password);

        SqlSessionFactory sqlSessionFactory = SqlSessionFactoryUtils.getSqlSessionFactory();

        SqlSession sqlSession = sqlSessionFactory.openSession();
        UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
        User u = userMapper.selectByUsername(username);

        /*判断查询出来的用户是否是存在的如果不存在就创建 */
        if (u == null) {
            userMapper.add(user);
            /*由于是增删改的操作所以我们需要进行提交事务*/
            sqlSession.commit();
            sqlSession.close();
        }else {
            response.setContentType("text/html;charset=utf-8");
            response.getWriter().write("用户名已经存在");

        }

    }
}

response

request

response request

upstream_response_time time request_time response

response request axios

response request amp

时长response request内容

javaweb-note response javaweb request

response request http 1.1

response request opaque return

response options request method

response对象request amp

526互联

response和request

request 和 response

request

response