HttpServlet超类在java构建路径中没有找到
https://jingyan.baidu.com/article/6c67b1d69a37a02787bb1ee2.html
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servlet处理http请求1
客户端发送http请求的方式
HttpServletRequest接口概述
获取http请求参数的方法
客户端发送http请求的方式
地址栏直接输入URL
超链接的href指定的URL
表单标签form的action指定的URL
javascript的location.href指定URL
HttpServletRequest接口
继承自ServletRequest接口，处理http请求
封装了http请求的请求url，请求参数，请求报文等信息
由容器实现，开发中直接从doMethod的参数中获取其实例
获取http请求参数的方法
从以do开头的方法中直接获取。
servlet处理http请求2
获取表单控件中的参数
处理console乱码，临时地加入下面一行
request.setCharacterEncoding("utf-8");
空字符串 用户名与密码未填写时
null 单选框未选中时
空指针 复选框一个都不选时
<%@ 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>
<a href="Servlet1?name=tom&name=jack&gender=male">请求1</a>
<form action="Servlet2" method="post">
<input type="text" name="username"/><br />
<input type="password" name="userpwd"/><br />
<input type="radio" name="gender" value="f" />女
<input type="radio" name="gender" value="m" />男<br />
<input type="checkbox" name="favors" value="football" />足球
<input type="checkbox" name="favors" value="music" />音乐
<input type="checkbox" name="favors" value="swim" />游泳<br />
<select name="cities">
<option value="1">内蒙</option>
<option value="2">河南</option>
<option value="3">河北</option>
</select><br />
<textarea rows="3" cols="3" name="description"></textarea>
<br /> <input type="submit" value="提交" />
</form>
</body>
</html>
package com.fgy;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
@WebServlet("/Servlet2")
public class Servlet2 extends HttpServlet {
private static final long serialVersionUID = 1L;
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
System.out.println("============================");
//临时地解决一下控制台中文乱码问题
request.setCharacterEncoding("utf-8");
String userName=request.getParameter("username");
System.out.println(userName);
System.out.println(request.getParameter("userpwd"));
System.out.println(request.getParameter("gender"));
String[] favors=request.getParameterValues("favors");
if (favors != null) {
for (String s : favors) {
System.out.println(s);
}
}
System.out.println(request.getParameter("cities"));
System.out.println(request.getParameter("description"));
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doGet(request, response);
}
}
servlet处理文件上传-1
文件上传方式概述
客户端编程要点
servlet内置的文件上传配置
使用part处理文件上传
part接口及获取其实例
在multipart请求中，每一个表单控件，都会被转换成一个part
使用HttpServletRequest获取Part:
getPart：返回指定名称的part，一个文件
getParts：返回请求中所有的part，多个文件
part接口的方法
part接口方法2
write
delete
getInputStream
servlet处理文件上传-2
文件上传的相关配置
服务器端处理文件上传要点
@MultipartConfig注解及属性
maxRequestSize
maxFileSize
location
fileSizeThreshold
如果location没有指定的话，就在下面这个路径，
全局属性的值javax.servlet.context.tmpdir
apache-tomcat-8.5.15workCatalinalocalhostproject3
如果在web.xml中配置，就要用到multipart的子标签，就是上面几个属性
前端展示页面
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<form action="Upload2" method="post" enctype="multipart/form-data">
<input type="file" name="file1"><br>
<input type="file" name="file2"><br>
<input type="text" name="name"><br>
<input type="submit" value="上传">
</form>
</body>
</html>
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后端处理逻辑
package com.fgy;
import java.io.IOException;
import java.util.Collection;
import javax.servlet.ServletException;
import javax.servlet.annotation.MultipartConfig;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.Part;
/**
* Servlet implementation class UploadServlet
*/
@WebServlet("/Upload2")
@MultipartConfig(maxRequestSize=1024*1024*10,maxFileSize=1024*1024*9,location="d:\")
public class UploadServlet2 extends HttpServlet {
private static final long serialVersionUID = 1L;
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
System.out.println("=========================");
System.out.println(request.getParameter("name"));
Collection<Part> parts=request.getParts();
for (Part part : parts) {
if (part.getContentType() != null) {
String fileName=part.getSubmittedFileName();
if (!fileName.equals("")) {
part.write(fileName);
}
}
}
}
}