文章目录
- 一、Java web技术栈
- 二、Http
- 1.1 Http请求数据格式
- 1.2 Http响应数据格式
- 1.3 状态码
- 二、Tomcat
- 2.1 介绍
- 2.2 web项目结构
- 2.3 IDEA中使用Tomcat
- 三、Servlet
- 3.1 Servlet使用
- 3.2 Servlet生命周期
- 3.3 Servlet方法和体系结构
- 3.4 urlPattern配置
- 四、Request
- 4.1 获取请求数据
- 4.2 通用方式获取请求参数
- 4.3 请求参数中文乱码问题
- 4.4 请求转发
- 五、Response
- 5.1 设置响应数据
- 5.2 重定向【注意:与请求转发区别】
- 5.3 响应 字符 / 字节 数据
- 五、项目小实战【用户登录注册】
一、Java web技术栈
二、Http
1.1 Http请求数据格式
1.2 Http响应数据格式
1.3 状态码
二、Tomcat
2.1 介绍
官网:https://tomcat.apache.org/
2.2 web项目结构
2.3 IDEA中使用Tomcat
方式一:
方式二:
三、Servlet
3.1 Servlet使用
3.2 Servlet生命周期
3.3 Servlet方法和体系结构
3.4 urlPattern配置
四、Request
request接受来自浏览器的请求数据
4.1 获取请求数据
package com.bhy.web.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.BufferedReader;
import java.io.IOException;
/**
* request 获取请求数据
*/
@WebServlet("/req1")
public class RequestDemo1 extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
// String getMethod():获取请求方式: GET
String method = req.getMethod();
System.out.println(method);//GET
// String getContextPath():获取虚拟目录(项目访问路径):/request-demo
String contextPath = req.getContextPath();
System.out.println(contextPath);
// StringBuffer getRequestURL(): 获取URL(统一资源定位符):http://localhost:8080/request-demo/req1
StringBuffer url = req.getRequestURL();
System.out.println(url.toString());
// String getRequestURI():获取URI(统一资源标识符): /request-demo/req1
String uri = req.getRequestURI();
System.out.println(uri);
// String getQueryString():获取请求参数(GET方式): username=zhangsan
String queryString = req.getQueryString();
System.out.println(queryString);
//------------
// 获取请求头:user-agent: 浏览器的版本信息
String agent = req.getHeader("user-agent");
System.out.println(agent);
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//获取post 请求体:请求参数
//1. 获取字符输入流
BufferedReader br = req.getReader();
//2. 读取数据
String line = br.readLine();
System.out.println(line);
}
}
4.2 通用方式获取请求参数
package com.bhy.web.request;
import javax.servlet.*;
import javax.servlet.http.*;
import javax.servlet.annotation.*;
import java.io.IOException;
import java.util.Map;
/**
* request 通用方式获取请求参数
*/
@WebServlet("/req2")
public class RequestDemo2 extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//1. 获取所有参数的Map集合
Map<String, String[]> map = req.getParameterMap();
for (String key : map.keySet()) {
// username:zhangsan lisi
System.out.print(key+":");
//获取值
String[] values = map.get(key);
for (String value : values) {
System.out.print(value + " ");
}
System.out.println();
}
System.out.println("------------");
//2. 根据key获取参数值,数组
String[] hobbies = req.getParameterValues("hobby");
for (String hobby : hobbies) {
System.out.println(hobby);
}
//3. 根据key 获取单个参数值
String username = req.getParameter("username");
String password = req.getParameter("password");
System.out.println(username);
System.out.println(password);
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//POST请求逻辑
this.doGet(req,resp);
}
}
4.3 请求参数中文乱码问题
package com.bhy.web.request;
import javax.servlet.*;
import javax.servlet.http.*;
import javax.servlet.annotation.*;
import java.io.IOException;
import java.nio.charset.StandardCharsets;
/**
* 中文乱码问题解决方案
*/
@WebServlet("/req4")
public class RequestDemo4 extends HttpServlet {
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// 解决乱码:
// 1.POST方式,getReader()
// 解决方法:request.setCharacterEncoding("UTF-8");//设置字符输入流的编码
//3. GET方式,获取参数的方式:getQueryString
// 乱码原因:tomcat进行URL解码,默认的字符集ISO-8859-1
//获取username
String username = request.getParameter("username");
System.out.println("解决乱码前:"+username);
/*
//3.1 先对乱码数据进行编码:转为字节数组
byte[] bytes = username.getBytes(StandardCharsets.ISO_8859_1);
//3.2 字节数组解码
username = new String(bytes, StandardCharsets.UTF_8);
*/
username = new String(username.getBytes(StandardCharsets.ISO_8859_1),StandardCharsets.UTF_8);
System.out.println("解决乱码后:"+username);
}
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doGet(request, response);
}
}
4.4 请求转发
@WebServlet("/req5")
public class RequestDemo5 extends HttpServlet {
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
System.out.println("demo5...");
System.out.println(request);
//存储数据
request.setAttribute("msg","hello");
//请求转发
request.getRequestDispatcher("/req6").forward(request,response);
}
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doGet(request, response);
}
}
@WebServlet("/req6")
public class RequestDemo6 extends HttpServlet {
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
System.out.println("demo6...");
System.out.println(request);
//获取数据
Object msg = request.getAttribute("msg");
System.out.println(msg);
}
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doGet(request, response);
}
}
五、Response
Response设置响应数据
5.1 设置响应数据
5.2 重定向【注意:与请求转发区别】
@WebServlet("/resp1")
public class ResponseDemo1 extends HttpServlet {
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
System.out.println("resp1....");
//重定向
/*//1.设置响应状态码 302
response.setStatus(302);
//2. 设置响应头 Location
response.setHeader("Location","/resp2");*/
//简化方式完成重定向
//动态获取虚拟目录
String contextPath = request.getContextPath();
response.sendRedirect(contextPath+"/resp2");
//response.sendRedirect("https://www.itcast.cn");
}
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doGet(request, response);
}
}
注意:虚拟目录问题,一般来说服务器使用(不需要加上虚拟目录),浏览器使用(需要加上虚拟目录)
5.3 响应 字符 / 字节 数据
@WebServlet("/resp3")
public class ResponseDemo3 extends HttpServlet {
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// 设置浏览器要解析html代码和字符集(解决乱码)
response.setContentType("text/html;charset=utf-8");
//1. 获取字符输出流
PrintWriter writer = response.getWriter();
//设置content-type目的,告诉浏览器解析HTML代码,例如下面的<h1></h1>
//response.setHeader("content-type","text/html");
writer.write("你好");
writer.write("<h1>aaa</h1>");
//细节:流不需要关闭
}
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doGet(request, response);
}
}
@WebServlet("/resp4")
public class ResponseDemo4 extends HttpServlet {
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//1. 读取文件
FileInputStream fis = new FileInputStream("d://a.jpg");
//2. 获取response字节输出流
ServletOutputStream os = response.getOutputStream();
//3. 完成流的copy
/* byte[] buff = new byte[1024];
int len = 0;
while ((len = fis.read(buff))!= -1){
os.write(buff,0,len);
}*/
IOUtils.copy(fis,os);
fis.close();
}
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doGet(request, response);
}
}
五、项目小实战【用户登录注册】
loglin.html
<!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="/request-response/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">
<a href="register.html">没有账号?点击注册</a>
</div>
</form>
</div>
</body>
</html>
register.html
<!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="/request-response/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>
LoginServlet.java
and RegisterServlet.java
@WebServlet("/loginServlet")
public class LoginServlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//1. 接收用户名和密码
String username = request.getParameter("username");
String password = request.getParameter("password");
//2. 调用MyBatis完成查询
//2.1 获取SqlSessionFactory对象
/* String resource = "mybatis-config.xml";
InputStream inputStream = Resources.getResourceAsStream(resource);
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);*/
SqlSessionFactory sqlSessionFactory = SqlSessionFactoryUtils.getSqlSessionFactory();
//2.2 获取SqlSession对象
SqlSession sqlSession = sqlSessionFactory.openSession();
//2.3 获取Mapper
UserMapper1 userMapper = sqlSession.getMapper(UserMapper1.class);
//2.4 调用方法
User user = userMapper.select(username, password);
//2.5 释放资源
sqlSession.close();
//获取字符输出流,并设置content type
response.setContentType("text/html;charset=utf-8");
PrintWriter writer = response.getWriter();
//3. 判断user释放为null
if(user != null){
// 登陆成功
writer.write("登陆成功");
}else {
// 登陆失败
writer.write("登陆失败");
}
}
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doGet(request, response);
}
}
@WebServlet("/registerServlet")
public class RegisterServlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//1. 接收用户数据
String username = request.getParameter("username");
String password = request.getParameter("password");
//封装用户对象
User user = new User();
user.setUsername(username);
user.setPassword(password);
//2. 调用mapper 根据用户名查询用户对象
//2.1 获取SqlSessionFactory对象
/* String resource = "mybatis-config.xml";
InputStream inputStream = Resources.getResourceAsStream(resource);
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);*/
SqlSessionFactory sqlSessionFactory = SqlSessionFactoryUtils.getSqlSessionFactory();
//2.2 获取SqlSession对象
SqlSession sqlSession = sqlSessionFactory.openSession();
//2.3 获取Mapper
UserMapper1 userMapper = sqlSession.getMapper(UserMapper1.class);
//2.4 调用方法
User u = userMapper.selectByUsername(username);
//3. 判断用户对象释放为null
if( u == null){
// 用户名不存在,添加用户
userMapper.add(user);
// 提交事务
sqlSession.commit();
// 释放资源
sqlSession.close();
}else {
// 用户名存在,给出提示信息
response.setContentType("text/html;charset=utf-8");
response.getWriter().write("用户名已存在");
}
}
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doGet(request, response);
}
}