Java Web：附件上传，两种文件上传限制格式及大小方法，学习笔记文件操作【诗书画唱】
附件上传：
package com.jy.controller;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.List;
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 org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
/**
* Servlet implementation class UploadServlet
*/
@WebServlet("/up")
public class UploadServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public UploadServlet() {
super();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
this.doPost(request, response);
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
//乱码处理
request.setCharacterEncoding("utf-8");
//创建附件上传工厂类
DiskFileItemFactory factory = new DiskFileItemFactory();
//创建文件上传对象
ServletFileUpload upload = new ServletFileUpload(factory);
//处理选中文件中的中文乱码的
upload.setHeaderEncoding("utf-8");
//设置文件的临界值大小是50K
//1024B就是1KB
factory.setSizeThreshold(1024 * 50);
//设置临时文件夹的路径
File file = new File("D:\\java\\JavaWebFuJianShangChuan\\WebContent\\img");
factory.setRepository(file);
//限制上传文件的大小最大是5MB
//1024KB就是1MB
upload.setSizeMax(1024 * 1024 * 20);
// 1024 * 1024 * 20就是 (1*1)MB*20=20MB
try {
//解析表单提交过来的数据
List<FileItem>list = upload.parseRequest(request);
//对list进行循环遍历
for(FileItem fi : list) {
//flag只有当type="file"的时候，才会为false
Boolean flag = fi.isFormField();
if(flag) {//正常的表单元素：文本输入框，密码输入框，单选框，多选框...
//正常表单元素的处理
}else {//就是type="file"的表单元素
//附件上传的处理
//获取你选中的文件在本机上的路径
String FileFullPath = fi.getName();
System.out.println("你选中的文件路径是：" + FileFullPath);
//根据本机上的路径创建文件对象
File f = new File(FileFullPath);
//获取文件名
String fileName = f.getName();
System.out.println("你选中的文件名是：" + fileName);
//获取文件的大小
long size = fi.getSize();
System.out.println("你选中的文件的大小是：" + size + "字节");
//获取工程所在的服务器的路径
String path = request.getServletContext().getRealPath("");
System.out.println(path);
//设置将选中的文件上传到服务器的项目的img文件夹下
String fPath = path + "\\img\\" + fileName;
System.out.println("选中的附件上传到项目中的文件位置是：" + fPath);
//进行附件的拷贝
//选中的文件流不能通过f获取，只能通过fi获取
InputStream is = fi.getInputStream();
OutputStream os = new FileOutputStream(fPath);
//进行拷贝
byte []buf = new byte[1024];
int len = 0;
while((len = is.read(buf)) != -1) {
os.write(buf,0,len);
}
//关闭文件流
os.close();
is.close();
}
}
} catch (FileUploadException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
<%@ page language="java" contentType="text/html;
charset=UTF-8" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"
+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base hreff="<%=basePath%>">
<title></title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content=
"keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<style type="text/css">
* {
font-size: 23px;
}
</style>
</head>
<body>
<h1>附件上传</h1>
<!-- 如果表单中要进行附件上传的话，
就必须添加enctype="multipart/form-data" -->
<form action="up" method="post" enctype="multipart/form-data">
<input type="text" placeholder="用户名" name="act" />
<br>
<input type="password" placeholder="密码" name="pwd" />
<br>
<input type="radio" name="sex" value="男" />男
<br>
<input type="radio" name="sex" value="女" />女
<br>
<input type="file" name="upload" />
<br>
<input type="submit" value="提交" />
</form>
</body>
</html>
1、实现附件上传功能。尝试对上传文件的类型进行限制，只能传图片(png,jpg)文件。
之前的都一样，就是jsp界面加上JS事件就可以了：
方法一：
<%@ page language="java" contentType="text/html;
charset=UTF-8" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"
+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base hreff="<%=basePath%>">
<title></title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content=
"keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<style type="text/css">
* {
font-size: 23px;
}
</style>
<script type="text/javascript">
var isIE = /msie/i.test(navigator.userAgent) && !window.opera;
function fileChange(target,id) {
var fileSize = 0;
var filetypes =[".jpg",".png"];
var filepath = target.value;
var filemaxsize = 1024*2;//2M
if(filepath){
var isnext = false;
var fileend = filepath.substring(filepath.lastIndexOf("."));
if(filetypes && filetypes.length>0){
for(var i =0; i<filetypes.length;i++){
if(filetypes[i]==fileend){
isnext = true;
break;
}
}
}
if(!isnext){
alert("不接受此文件类型！只能传图片(png,jpg)文件");
target.value ="";
return false;
}
}else{
return false;
}
if (isIE && !target.files) {
var filePath = target.value;
var fileSystem = new ActiveXObject("Scripting.FileSystemObject");
if(!fileSystem.FileExists(filePath)){
alert("附件不存在，请重新输入！");
return false;
}
var file = fileSystem.GetFile (filePath);
fileSize = file.Size;
} else {
fileSize = target.files[0].size;
}
var size = fileSize / 1024;
if(size>filemaxsize){
alert("附件大小不能大于"+filemaxsize/1024+"M！");
target.value ="";
return false;
}
if(size<=0){
alert("附件大小不能为0M！");
target.value ="";
return false;
}
}
</script>
</head>
<body>
<h1>附件上传</h1>
<!-- 如果表单中要进行附件上传的话，
就必须添加enctype="multipart/form-data" -->
<form action="up" method="post" enctype="multipart/form-data">
<input type="text" placeholder="用户名" name="act" />
<br>
<input type="password" placeholder="密码" name="pwd" />
<br>
<input type="radio" name="sex" value="男" />男
<br>
<input type="radio" name="sex" value="女" />女
<br>
<input type="file" name="upload" onchange="fileChange(this);"/>
<br>
<input type="submit" value="提交" />
</form>
</body>
</html>
方法二：
前面基本一样，jsp界面的js事件去掉，就是下面的变一下：
package com.SSHC.controller;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.List;
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 org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
/**
* Servlet implementation class UploadServlet
*/
@WebServlet("/up")
public class UploadServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public UploadServlet() {
super();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
this.doPost(request, response);
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
//乱码处理
request.setCharacterEncoding("utf-8");
//创建附件上传工厂类
DiskFileItemFactory factory = new DiskFileItemFactory();
//创建文件上传对象
ServletFileUpload upload = new ServletFileUpload(factory);
//处理选中文件中的中文乱码的
upload.setHeaderEncoding("utf-8");
//设置文件的临界值大小是50K
//1024B就是1KB
factory.setSizeThreshold(1024 * 200);
//设置临时文件夹的路径
File file = new File("d:\\temp");
factory.setRepository(file);
//限制上传文件的大小最大是5MB
//1024KB就是1MB
upload.setSizeMax(1024 * 1024 * 20);
try {
//解析表单提交过来的数据
List<FileItem>list = upload.parseRequest(request);
//对list进行循环遍历
for(FileItem fi : list) {
//flag只有当type="file"的时候，才会为false
Boolean flag = fi.isFormField();
if(flag) {//正常的表单元素：文本输入框，密码输入框，单选框，多选框...
//正常表单元素的处理
}else {//就是type="file"的表单元素
//附件上传的处理
//获取你选中的文件在本机上的路径
String FileFullPath = fi.getName();
System.out.println("你选中的文件路径是：" + FileFullPath);
//根据本机上的路径创建文件对象
File f = new File(FileFullPath);
//获取文件名
String fileName = f.getName();
System.out.println("你选中的文件名是：" + fileName);
//获取选中文件的后缀名
//获取到文件中最后一个.的索引
int index = fileName.lastIndexOf('.');
//根据.的位置进行截取
String fix = fileName.substring(index + 1);
System.out.println("文件的后缀名是：" + fix);
//如果后缀名是png,jpg或者gif，就进行附件上传
if(fix.equals("png") || fix.equals("jpg")
|| fix.equals("gif")) {
//获取文件的大小
long size = fi.getSize();
System.out.println("你选中的文件的大小是：" + size + "字节");
//获取工程所在的服务器的路径
String path = request.getServletContext().getRealPath("");
System.out.println(path);
//设置将选中的文件上传到服务器的项目的img文件夹下
String fPath = path + "\\img\\" + fileName;
System.out.println("选中的附件上传到项目中的文件位置是：" + fPath);
//进行附件的拷贝
//选中的文件流不能通过f获取，只能通过fi获取
InputStream is = fi.getInputStream();
OutputStream os = new FileOutputStream(fPath);
//进行拷贝
byte []buf = new byte[1024];
int len = 0;
while((len = is.read(buf)) != -1) {
os.write(buf,0,len);
}
//关闭文件流
os.close();
is.close();
//http://localhost:8888/j1908021/img/4.png
String p = request.getContextPath();
System.out.println("工程名是：" + p);
String basePath = request.getScheme() + "://" +
request.getServerName() + ":" + request.getServerPort()
+ p + "/";
//获取上传的图片在服务器上的路径
String imgPath = basePath + "img\\" + fileName;
System.out.println("图片的显示路径是：" + imgPath);
//将图片的路径传递到show.jsp页面去
request.setAttribute("imgPath", imgPath);
//上传成功以后，跳转到一个show.jsp页面
request.getRequestDispatcher("show.jsp")
.forward(request, response);
} else {
response.setCharacterEncoding("gbk");
response.getWriter().write("选中的文件不是一个图片，无法上传");
}
}
}
} catch (FileUploadException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
2、在两台电脑之间进行附件上传的操作。
3、学会使用cmd命令：ipconfig查看服务器的ip地址，ping检查跟指定的ip地址的电脑是否连接在同一个网内的
ping 192.168.42.133就是检查你的电脑跟这个ip地址的电脑是否连接在一起了。
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