目前文件上传的(框架)组件:Apache----fileupload 、Orialiy – COS – 2008() 、Jsp-smart-upload – 200M。
用fileupload上传文件:
需要导入第三方包: Apache-fileupload.jar – 文件上传核心包。 Apache-commons-io.jar – 这个包是fileupload的依赖包。同时又是一个工具包。
核心类: DiskFileItemFactory – 设置磁盘空间,保存临时文件。只是一个具类。 ServletFileUpload - 文件上传的核心类,此类接收request,并解析reqeust ServletFileUpload.parseRequest(request); --List<FileItem> 解析request 一个FileItem就是一个标识分隔符开始 到结束。如下图:
查看DiskFileItemFactory源代码,可知
If not otherwise configured, the default configuration values are as
follows:
Size threshold is 10KB.
Repository is the system default temp directory, as returned by
System.getProperty("java.io.tmpdir")
可知,如果不设置临时目录,会保存在默认的临时目录- System.getProperty("java.io.tmpdir");这个目录正是windows系统的临时文件存放目录,通过环境变量,可找到这个目录
这里存放着许多临时文件。
单文件上传Servlet:
package com.lhy.upload;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
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;
@WebServlet(name="Up2Servlet",urlPatterns="/Up2Servlet")
public class Up2Servlet extends HttpServlet{
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
this.doPost(req, resp);
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
req.setCharacterEncoding("UTf-8");
//获取tomcat下的up目录的路径
String path = getServletContext().getRealPath("/up");
//临时文件目录
String tmpPath = getServletContext().getRealPath("/tmp");
//检查我们是否有文件上传请求
boolean isMultipart = ServletFileUpload.isMultipartContent(req);
//1,声明DiskFileItemFactory工厂类,用于在指定磁盘上设置一个临时目录
DiskFileItemFactory disk = new DiskFileItemFactory(1024*10,new File(tmpPath));
//2,声明ServletFileUpload,接收上边的临时文件。也可以默认值
ServletFileUpload up = new ServletFileUpload(disk);
//3,解析request
try {
List<FileItem> list = up.parseRequest(req);
//如果就一个文件,
FileItem file = list.get(0);
//获取文件名:
String fileName = file.getName();
//获取文件的类型:
String fileType = file.getContentType();
//获取文件的字节码:
InputStream in = file.getInputStream();
//文件大小
int size = file.getInputStream().available();
//声明输出字节流
OutputStream out = new FileOutputStream(path+"/"+fileName);
//文件copy
byte[] b = new byte[1024];
int len = 0;
while((len=in.read(b))!=-1){
out.write(b, 0, len);
}
out.flush();
out.close();
//删除上传生成的临时文件
file.delete();
//显示数据
resp.setContentType("text/html;charset=UTF-8");
PrintWriter pw = resp.getWriter();
pw.println("文件名:"+fileName);
pw.println("文件类型:"+fileType);
pw.println("<br/>文件大小(byte):"+size);
} catch (FileUploadException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}
from:
<form action="<%=basePath%>Up2Servlet" method="post" enctype="multipart/form-data">
File1:<input type="file" name="txt"><br/>
<input type="submit"/>
</form>
临时文件:
服务端:
响应:
实际项目中都是有文件服务器的,公司一般都提供了上传到文件服务器接口,有的是上传一个file类型,有的是流。
多文件上传Servlet:
package com.lhy.upload;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
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.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
import org.apache.commons.io.FileUtils;
@WebServlet(name="Up3Servlet",urlPatterns="/Up3Servlet")
public class Up3Servlet extends HttpServlet{
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
this.doPost(req, resp);
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
req.setCharacterEncoding("UTf-8");
String path = getServletContext().getRealPath("/up");
//临时文件目录
String tmpPath = getServletContext().getRealPath("/tmp");
//声明disk
DiskFileItemFactory disk = new DiskFileItemFactory();
disk.setSizeThreshold(1024*1024);
disk.setRepository(new File(tmpPath));
//声明解析requst的servlet
ServletFileUpload up = new ServletFileUpload(disk);
try{
//解析requst
List<FileItem> list = up.parseRequest(req);
//声明一个list<map>封装上传的文件的数据
List<Map<String,String>> ups = new ArrayList<Map<String,String>>();
for(FileItem file:list){
Map<String,String> mm = new HashMap<String, String>();
//获取文件名
String fileName = file.getName();
fileName = fileName.substring(fileName.lastIndexOf("\\")+1);
String fileType = file.getContentType();
InputStream in = file.getInputStream();
int size = in.available();
//使用工具类
// FileUtils.copyInputStreamToFile(in,new File(path+"/"+fileName));
//file 的方法可以直接写出文件
file.write(new File(path+"/"+fileName));
mm.put("fileName",fileName);
mm.put("fileType",fileType);
mm.put("size",""+size);
ups.add(mm);
file.delete();
}
req.setAttribute("ups",ups);
//转发
req.getRequestDispatcher("/jsps/show.jsp").forward(req, resp);
}catch(Exception e){
e.printStackTrace();
}
}
}
表单:
<form name="xx" action="<%=basePath%>Up3Servlet" method="post" enctype="multipart/form-data">
<table id="tb" border="1">
<tr>
<td>
File:
</td>
<td>
<input type="file" name="file">
<button onclick="_del(this);">删除</button>
</td>
</tr>
</table>
<br/>
<input type="button" onclick="_submit();" value="上传">
<input onclick="_add();" type="button" value="增加">
</form>
js
<script type="text/javascript">
function _add(){
var tb = document.getElementById("tb");
//写入一行
var tr = tb.insertRow();
//写入列
var td = tr.insertCell();
//写入数据
td.innerHTML="File:";
//再声明一个新的td
var td2 = tr.insertCell();
//写入一个input
td2.innerHTML='<input type="file" name="file"/><button onclick="_del(this);">删除</button>';
}
function _del(btn){
var tr = btn.parentNode.parentNode;
//alert(tr.tagName);
//获取tr在table中的下标
var index = tr.rowIndex;
//删除
var tb = document.getElementById("tb");
tb.deleteRow(index);
}
function _submit(){
//遍历所的有文件
var files = document.getElementsByName("file");
if(files.length==0){
alert("没有可以上传的文件");
return false;
}
for(var i=0;i<files.length;i++){
if(files[i].value==""){
alert("第"+(i+1)+"个文件不能为空");
return false;
}
}
document.forms['xx'].submit();
}
</script>
show.jsp:
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>My JSP 'index.jsp' starting page</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">
</head>
<body>
<p>以下是你上传的文件</p>
<c:forEach items="${ups}" var="mm">
文件名:${mm.fileName}<br/>
类型:${mm.fileType}<br/>
大小:${mm.size}(bytes)
<hr/>
</c:forEach>
</body>
</html>
测试,上传3张图片:
up目录L:
响应:
多文件上传,如果是同一个文件,会覆盖以前的,需要重命名,具体自己实现吧,如用uuid//获取扩展String extName = fileName.substring(fileName.lastIndexOf("."));//.jpg//UUIDString uuid = UUID.randomUUID().toString().replace("-", "");//新名称String newName = uuid+extName;
限制只能上传图片:
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
req.setCharacterEncoding("UTF-8");
String path = getServletContext().getRealPath("/up");
//项目里建的临时目录,存放临时文件,linux适用
String tmpPath = getServletContext().getRealPath("/tmp");
DiskFileItemFactory disk =
new DiskFileItemFactory(1024*10,new File(tmpPath));
ServletFileUpload up = new ServletFileUpload(disk);
try{
List<FileItem> list = up.parseRequest(req);
//只接收图片*.jpg-iamge/jpege.,bmp/imge/bmp,png,
List<String> imgs = new ArrayList<String>();
for(FileItem file :list){
if(file.getContentType().contains("image/")){
String fileName = file.getName();
//如果是原始方式Servlet上传,IE:c:\\xxx\\aa.jpg,但是用框架ie也是aa.jpg,这句没啥用好似
fileName = fileName.substring(fileName.lastIndexOf("\\")+1);
//获取扩展
String extName = fileName.substring(fileName.lastIndexOf("."));//.jpg
//UUID
String uuid = UUID.randomUUID().toString().replace("-", "");
//新名称
String newName = uuid+extName;
FileUtils.copyInputStreamToFile(file.getInputStream(),
new File(path+"/"+newName));
//放到list
imgs.add(newName);
}
file.delete();
}
req.setAttribute("imgs",imgs);
req.getRequestDispatcher("/jsps/imgs.jsp").forward(req, resp);
}catch(Exception e){
e.printStackTrace();
}
}
imgs.jsp:显示上传的图片
<body>
<p>图片是:</p>
<c:forEach items="${imgs}" var="img">
<img src="<c:url value='/up/${img}'/>"></img>
</c:forEach>
</body>
处理表单域中普通的input:
指定表单的enctype="multipart/form-data" 后,表单将会以二进制请求,普通的input 用request.getParameter("xxx");为null,fileupload能很方便处理普通表单域:
FileItem接口方法:
void | delete () 删除保存在临时目录中的文件。 |
| |
String | getContentType() 获取文档的类型 Returns the content type passed by the browser or null if not defined. |
String | getFieldName() 获取字段的名称,即name=xxxx Returns the name of the field in the multipart form corresponding to this file item.<input type=”file” name=”img”/> |
InputStream | getInputStream() Returns an InputStream that can be used to retrieve the contents ofthe file. |
String | getName() Returns the original filename in the client's filesystem, as provided by the browser (or other client software).获取文件名称。如果是在IE获取的文件为 c:\aaa\aaa\xxx.jpg –即完整的路径。非IE;文件名称只是 xxx.jpg |
| |
long | getSize() 获取文件大小 相当于in.avilivable(); Returns the size of the file item |
如果你上传是一普通的文本元素,则可以通过以下方式获取元素中的数据<form enctype=”multipart/form-data”> <input type=”text” name=”name”/> |
String | getString() 用于获取普通的表单域的信息。 Returns the contents of the file item as a String, using the default character encoding.(IOS-8859-1) |
String | getString(String encoding)可以指定编码格式 Returns the contents of the file item as a String, using the specified encoding. |
void | write(File file)直接将文件保存到另一个文件中去。 A convenience method to write an uploaded item to disk. |
以下文件用判断一个fileItem是否是file(type=file)对象或是text(type=text|checkbox|radio)对象: |
boolean | isFormField () 如果是text|checkbox|radio|select这个值就是true. Determines whether or not a FileItem instance represents a simple form field. |
Servlet:
package com.lhy.upload;
import java.io.File;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.UUID;
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.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
@WebServlet(name="UpDescServlet",urlPatterns="/UpDescServlet")
public class UpDescServlet extends HttpServlet {
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
//可以获取中文的文件名
request.setCharacterEncoding("UTF-8");
//项目真实路径
String path = getServletContext().getRealPath("/up");
//声明disk
DiskFileItemFactory disk = new DiskFileItemFactory();
disk.setRepository(new File("D:/tmp"));//临时文件目录
try{
//声明解析requst的servlet
ServletFileUpload up = new ServletFileUpload(disk);
//解析requst
List<FileItem> list = up.parseRequest(request);
//声明一个map用于封装信息
Map<String,Object> img = new HashMap<String, Object>();
for(FileItem file:list){
//第一步:判断是否是普通的表单项
if(file.isFormField()){
//可以读取多个普通的input
String fileName = file.getFieldName();//<input type="text" name="desc">=desc
String value = file.getString("UTF-8");//默认以ISO方式读取数据
System.err.println(fileName+"="+value);
//放入图片的说明
img.put(fileName,value);
}else{//说明是一个文件
String fileName = file.getName();//以前的名称
//处理文件名
fileName = fileName.substring(fileName.lastIndexOf("\\")+1);
img.put("oldName",fileName);
//修改名称
String extName = fileName.substring(fileName.lastIndexOf("."));
String newName =
UUID.randomUUID().toString().replace("-", "")+extName;
//保存新的名称
img.put("newName",newName);
file.write(new File(path+"/"+newName));
System.err.println("文件名是:"+fileName);
System.err.println("文件大小是:"+file.getSize());
img.put("size",file.getSize());
file.delete();
}
}
//将img=map放到req
request.setAttribute("img",img);
//转发
request.getRequestDispatcher("/jsps/desc.jsp").forward(request, response);
}catch(Exception e){
e.printStackTrace();
}
}
}
form表单:
<form action="<c:url value='/UpDescServlet'/>" method="post"
enctype="multipart/form-data">
你的图片:<input type="file" name="img"><br />
说明:<input type="text" name="desc"/><br/>
说明2:<input type="text" name="desc2"/><br/>
<input type="submit" />
</form>
desc.jsp:
<body>
<p>请选择图片:名称(以前的名称oldName),顯示這張圖片newName。图片大小size,图片的说明desc</p>
${img.oldName}<br/>
${img.size}<br/>
${img.desc}<br/>
${img.desc2} <br/>
<img width="300" height="300" src="<c:url value='/up/${img.newName}'/>"></img>
<hr/>
<p>url:http://localhost:8080/day22/jsps/desc.jsp
<img width="300" height="300" src="<c:url value='/up/8.jpg'/>"/>
</body>
</html>
性能提升?使用FileItemIterator上传:
package com.lhy.upload;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.util.Date;
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.FileItemIterator;
import org.apache.commons.fileupload.FileItemStream;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
import org.apache.commons.io.FileUtils;
@WebServlet(name="FastServlet",urlPatterns="/FastServlet")
public class FastServlet extends HttpServlet{
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
long start = new Date().getTime();
req.setCharacterEncoding("UTF-8");
String path = getServletContext().getRealPath("/up");
DiskFileItemFactory disk = new DiskFileItemFactory();
try {
ServletFileUpload up = new ServletFileUpload(disk);
//迭代器模式
FileItemIterator iter = up.getItemIterator(req);
while(iter.hasNext()){
FileItemStream item = iter.next();
String fileName = item.getName();
fileName = fileName.substring(fileName.lastIndexOf("\\")+1);
InputStream in = item.openStream();
FileUtils.copyInputStreamToFile(in, new File(path+"/"+fileName));
}
} catch (Exception e) {
e.printStackTrace();
}
long end = new Date().getTime();
System.out.println(end - start);
}
}
不知道能不能提升性能,我分别用这个和上边的上传了一个myeclipse2014安装包1.1G,用上传前后的毫秒差计算,结果显示这个耗时100930,上边的方法耗时54240,并没有提升性能反而满了,迭代器模式不知道能不能提升性能,。。
限制上传文件的大小:
ServletFileUpload类的方法:1:限制总文件的大小 。 如 上传10文件,设置最多总上传大小为100M。
void | setSizeMax (long sizeMax) Sets the maximum allowed size of a complete request, as opposed to setFileSizeMax(long) . |
2:设置第每一个文件的大小 ,如果设置每 一个文件大小10M。
void | setFileSizeMax (long fileSizeMax) Sets the maximum allowed size of a single uploaded file, as opposed to getSizeMax() . |
两者一般设置一个就行了,可以catch到这个异常给提示信息。
ServletFileUpload up = new ServletFileUpload(disk);
//限制总文件的大小,如果上传多个文件
up.setSizeMax(1024*1024*100);//限制上传最大100M
//设置第每一个文件的大小 两者有一个即可
// up.setFileSizeMax(1024*1024);
有些上传插件,如插件fileuploadify 在页面就可以限制上传文件
转载自:https://www.cnblogs.com/lihaoyang/p/7295434.html?utm_source=itdadao&utm_medium=referral