JavaWeb笔记

Posted 2020-10-11 范仁义

tags:

篇首语：本文由小常识网(cha138.com)小编为大家整理，主要介绍了JavaWeb笔记相关的知识，希望对你有一定的参考价值。

JavaWeb笔记

一、servlet

真正helloServlet所在的位置

HelloServlet.java

package net.zixue.servlet;

import jdk.nashorn.internal.runtime.arrays.IteratorAction;

import javax.lang.model.element.NestingKind;

import javax.servlet.ServletConfig;

import javax.servlet.ServletException;

import javax.servlet.ServletOutputStream;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import java.io.IOException;

import java.io.PrintWriter;

import java.util.Enumeration;

import java.util.Iterator;

import java.util.Map;

/**

* Created by invinjun on 2017/5/25.

public class HelloServlet extends HttpServlet{

@Override

public void init() throws ServletException {

super.init();

ServletConfig servletConfig = this.getServletConfig();

String encoding = servletConfig.getInitParameter("encoding");

System.out.println("encoding="+encoding);

}

@Override

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

//获取请求行

// System.out.println("接收到get请求");

// System.out.println("请求方式："+request.getMethod());

// System.out.println("URI："+request.getRequestURI());

// System.out.println("发出请求客户端IP地址："+request.getRemoteAddr());

// System.out.println("服务点接收请求的IP地址："+request.getLocalAddr());

// System.out.println("访问客户端的端口号："+request.getRemotePort());

// System.out.println("web应用路径："+request.getContextPath());

// System.out.println("http协议和版本："+request.getProtocol());

// //获取请求头

// Enumeration<String> headerNames = request.getHeaderNames();

// while (headerNames.hasMoreElements()){

// String element = headerNames.nextElement();

// System.out.println(element+":"+request.getHeader(element));

// }

// //获取请求参数

// String name = request.getParameter("name");

// String passWord = request.getParameter("passWord");

// System.out.println("用户名："+name);

// System.out.println("密码："+passWord);

// String result="恭喜您登录成功";

//// ServletOutputStream outputStream = response.getOutputStream();

//// outputStream.write(result.getBytes());

// response.setContentType("text/html;charset=utf-8");

// PrintWriter writer = response.getWriter();

// writer.write(result);

request.setAttribute("name","123");

request.getRequestDispatcher("/index.jsp").forward(request,response);

}

@Override

protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

System.out.println("接收到post请求");

}

web.xml

<?xml version="1.0" encoding="UTF-8"?>

<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"

xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"

version="3.1">

<session-config>

<session-timeout>10</session-timeout>

</session-config>

<context-param>

<param-name>encoding</param-name>

<param-value>utf-8</param-value>

</context-param>

<context-param>

<param-name>encoding1</param-name>

<param-value>utf-8</param-value>

</context-param>

<servlet-name>helloServlet</servlet-name>

<servlet-class>net.zixue.servlet.HelloServlet</servlet-class>

</servlet>

<servlet-mapping>

<servlet-name>helloServlet</servlet-name>

<url-pattern>/hi</url-pattern>

</servlet-mapping>

</web-app>

二、cookie

TimeServlet.java

package net.zixue.cookie;

import javax.servlet.ServletException;

import javax.servlet.annotation.WebServlet;

import javax.servlet.http.Cookie;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import java.io.IOException;

import java.text.SimpleDateFormat;

import java.util.Date;

/**

* Created by invinjun on 2017/6/9.

@WebServlet(name = "TimeServlet", urlPatterns = "/time")

public class TimeServlet extends HttpServlet {

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

}

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

//记录访问时间并其通过cookie加入到响应头

Date date = new Date();

SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyyMMdd-hh:mm:ss");

String time = simpleDateFormat.format(date);

Cookie cookie = new Cookie("time", time);

cookie.setMaxAge(60*60*24);

response.addCookie(cookie);

response.setContentType("text/html;charset=utf-8");

//获取客户端浏览器发送过来的cookie数据

Cookie[] cookies = request.getCookies();

String timeValue = null;

for (Cookie cookie1 : cookies) {

if (cookie1.getName().equals("time")) {

timeValue = cookie1.getValue();

}

if (timeValue == null) {

response.getWriter().write("欢迎您访问我们的网站");

} else {

response.getWriter().write("您上次访问网站的时间是：" + timeValue);

}

三、JSP

JSP做页面，servlet做处理

JSP的9大内置对象

四、EL表达式+JSTL标签

servlet获取数据，传给jsp页面，jsp页面显示数据

PhoneListServlet.java

package net.zixue.JSP;

import net.zixue.bean.Phone;

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.ArrayList;

import java.util.List;

/**

* Created by invinjun on 2017/6/16.

@WebServlet(name = "PhoneListServlet",urlPatterns = "/phoneList")

public class PhoneListServlet extends HttpServlet {

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

}

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

//通过servlet从数据库中获取数据，我们这里暂时通过手动创建数据

Phone phone=new Phone();

phone.setName("iphone6");

phone.setId(001);

phone.setImage("https://img10.360buyimg.com/n7/jfs/t277/193/1005339798/768456/29136988/542d0798N19d42ce3.jpg");

phone.setPrice("3900");

Phone phone1=new Phone();

phone1.setName("坚果pro");

phone1.setId(002);

phone1.setPrice("1799");

phone1.setImage("https://img13.360buyimg.com/n7/jfs/t5377/56/1578379545/209772/32105f74/5911bcbdN7afa707b.jpg");

Phone phone2=new Phone();

phone2.setName("vivo x9");

phone2.setPrice("2345");

phone2.setId(003);

phone2.setImage("https://img12.360buyimg.com/n7/jfs/t6067/340/2101390376/231820/750cc50e/593aa83fN8b0829fc.jpg");

Phone phone3=new Phone();

phone3.setName("oppo A57");

phone3.setId(004);

phone3.setPrice("1399");

phone3.setImage("https://img10.360buyimg.com/n7/jfs/t4978/185/135948089/78285/f6a84203/58db6fa4N354322d9.jpg");

Phone phone4=new Phone();

phone4.setName("诺基亚6");

phone4.setId(005);

phone4.setPrice("1699");

phone4.setImage("https://img11.360buyimg.com/n7/jfs/t4930/86/192598423/86027/36a57ccf/58dcbfa5N5c41cbfd.jpg");

Phone phone5=new Phone();

phone5.setName("小米MIX");

phone5.setId(006);

phone5.setPrice("3999");

phone5.setImage("https://img13.360buyimg.com/n7/jfs/t4264/215/455518113/309855/38fe41f1/58b4fc81N1d924112.jpg");

List<Phone> list=new ArrayList<>();

list.add(phone);

list.add(phone1);

list.add(phone2);

list.add(phone3);

list.add(phone4);

list.add(phone5);

request.setAttribute("list",list);

request.getRequestDispatcher("/phone_list.jsp").forward(request,response);

}

phone_list.jsp

<%--

Created by IntelliJ IDEA.

User: invinjun

Date: 2017/6/16

Time: 16:57

To change this template use File | Settings | File Templates.

--%>

<%@ page contentType="text/html;charset=UTF-8" language="java" %>

<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>

<!DOCTYPE html>

<html>

<head>

</head>

<body>

<c:forEach items="${list}" var="phone">

</a>

<p>

<a href="product_info.html" style=\'color: green\'>${phone.name}</a>

</p>

<p>

<font color="#FF0000">商城价：¥${phone.price}</font>

</p>

</div>

</c:forEach>

</body>

</html>

bootstrap.min.css（前30行）

/*!

* Bootstrap v3.3.5 (http://getbootstrap.com)

* Licensed under MIT (https://github.com/twbs/bootstrap/blob/master/LICENSE)

/*! normalize.css v3.0.3 | MIT License | github.com/necolas/normalize.css */

html {

font-family: sans-serif;

-webkit-text-size-adjust: 100%;

-ms-text-size-adjust: 100%

}

body {

margin: 0

}

article, aside, details, figcaption, figure, footer, header, hgroup,

main, menu, nav, section, summary {

display: block

}

audio, canvas, progress, video {

display: inline-block;

vertical-align: baseline

}

audio:not ([controls] ){

display: none;

height: 0

}

Phone.java

package net.zixue.bean;

/**

* Created by invinjun on 2017/6/16.

public class Phone {

private int id;

private String name;

private String image;

private String price;

public int getId() {

return id;

}

public void setId(int id) {

this.id = id;

}

public String getName() {

return name;

}

public void setName(String name) {

this.name = name;

}

public String getImage() {

return image;

}

public void setImage(String image) {

this.image = image;

}

public String getPrice() {

return price;

}

public void setPrice(String price) {

this.price = price;

}

五、SQL注入

Login.java

package net.zixue.crud;

import net.zixue.utils.JDBCUtil;

import java.math.BigDecimal;

import java.sql.*;

/**

* Created by Administrator on 2017/6/24.

public class Login {

public void login(String account,String password) throws ClassNotFoundException, SQLException {

Connection connection = JDBCUtil.getConnection();

// 3.获取操作数据库的对象

Statement statement = connection.createStatement();

String sql="select * from user WHERE account=\'"+account+"\' AND password=\'"+password+"\'";

ResultSet resultSet = statement.executeQuery(sql);

// 4. 取出数据

if (resultSet.next()){

String name=resultSet.getString("nickname");

System.out.println(name+"登录成功" );

}else{

System.out.println("登陆失败");

}

release(connection, statement, resultSet);

}

private void release(Connection connection, Statement statement, ResultSet resultSet) throws SQLException {

resultSet.close();

statement.close();

connection.close();

}

public void login1(String account,String password) throws ClassNotFoundException, SQLException {

Class.forName("com.mysql.jdbc.Driver");

// 2.获取数据库连接

String url="jdbc:mysql://localhost:3306/mall";

Connection connection = DriverManager.getConnection(url, "root", "root");

// 3.获取操作数据库的对象

// Statement statement = connection.createStatement();

String sql="select * from user WHERE account=? AND password=?";

PreparedStatement preparedStatement = connection.prepareStatement(sql);

// ResultSet resultSet = statement.executeQuery(sql);

preparedStatement.setString(1,account);

preparedStatement.setString(2,password);

ResultSet resultSet = preparedStatement.executeQuery();

// 4. 取出数据

if (resultSet.next()){

String name=resultSet.getString("nickname");

System.out.println(name+"登录成功" );

}else{

System.out.println("登录失败");

}

resultSet.close();

preparedStatement.close();

connection.close();

}

LoginTest.java

package net.zixue.crud;

import org.junit.Test;

import static org.junit.Assert.*;

/**

* Created by Administrator on 2017/6/24.

public class LoginTest {

@Test

public void login() throws Exception {

}

JDBCUtil.java

package net.zixue.utils;

import java.io.IOException;

import java.io.InputStream;

import java.sql.*;

import java.util.Properties;

/**

* Created by Administrator on 2017/6/24.

public class JDBCUtil {

private static String driver;

private static String url;

private static String username;

private static String password;

//静态代码块初始化配置文件信息

static {

try {

ClassLoader classLoader = JDBCUtil.class.getClassLoader();

InputStream resourceAsStream = classLoader.getResourceAsStream("db.propertise");

Properties properties=new Properties();

properties.load(resourceAsStream);

driver = properties.getProperty("driver");

url = properties.getProperty("url");

username = properties.getProperty("username");

password = properties.getProperty("password");

} catch (IOException e) {

e.printStackTrace();

}

public static Connection getConnection() {

Connection connection = null;

//注册驱动，获取连接

try {

Class.forName(driver);

connection = DriverManager.getConnection(url, username, password);

} catch (Exception e) {

e.printStackTrace();

}

return connection;

}

public static void release(Connection connection, PreparedStatement preparedStatement, ResultSet resultSet) {

//释放资源

if (resultSet != null) {

try {

resultSet.close();

} catch (SQLException e) {

e.printStackTrace();

}

if (preparedStatement != null) {

try {

preparedStatement.close();

} catch (SQLException e) {

e.printStackTrace();

}

if (connection != null) {

try {

connection.close();

} catch (SQLException e) {

e.printStackTrace();

}

修改代码很复杂，但是修改配置文件很简单

还有就是注意一下上面为什么使用静态代码块

db.propertise

driver=com.mysql.jdbc.Driver

url=jdbc:mysql://localhost:3306/mall

username=root

password=root

以上是关于JavaWeb笔记的主要内容，如果未能解决你的问题，请参考以下文章