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JAVA文件上传总结

2014年10月02日 ⁄ 综合 ⁄ 共 9032字 ⁄ 字号 小 中 大 ⁄ 评论关闭

        文件上传有很多组件，我们只要学会下面几种就OK了：

1 APACHE  FILEUPLOAD：

   

将Apache的commons-fileupload.jar放在应用程序的WEB-INF\lib下，即可使用。下面举例介绍如何使用它的文件上传功能。

所使用的fileUpload版本为1.2，环境为Eclipse3.3+MyEclipse6.0。FileUpload 是基于 Commons IO的，所以在进入项目前先确定Commons IO的jar包（本文使用commons-io-1.3.2.jar）在WEB-INF\lib下。
此文作示例工程可在文章最后的附件中下载。
示例1
最简单的例子，通过ServletFileUpload静态类来解析Request，工厂类FileItemFactory会对mulipart类的表单中的所有字段进行处理，不只是file字段。getName（）得到文件名，getString（）得到表单数据内容，isFormField（）可判断是否为普通的表单项。
demo1.html
<html>
<head>
   
<meta http-equiv="Content-Type"
content="text/html; charset=GB18030">
   
<title>File upload</title>
</head>
<body>
       //必须是multipart的表单数据。
   
<form name="myform"
action="demo1.jsp"
method="post"
      
enctype="multipart/form-data">
      
Your name: <br>
      
<input type="text"
name="name"
size="15"><br>
      
File:<br>
      
<input type="file"
name="myfile"><br>
      
<br>
      
<input type="submit"
name="submit"
value="Commit">
   
</form>
</body>
</html>
 
demo1.jsp
<%@
page language="java"
contentType="text/html; charset=GB18030"
   
pageEncoding="GB18030"%>
<%@
page import="org.apache.commons.fileupload.*"%>
<%@
page import="org.apache.commons.fileupload.servlet.*"%>
<%@
page import="org.apache.commons.fileupload.disk.*"%>
<%@
page import="java.util.*"%>
 
<!DOCTYPE
HTML PUBLIC
"-//W3C//DTD HTML 4.01 Transitional//EN">
<%
   
boolean isMultipart = ServletFileUpload.isMultipartContent(request);//检查输入请求是否为multipart表单数据。
   
if (isMultipart ==
true) {
      
FileItemFactory factory = new DiskFileItemFactory();//为该请求创建一个DiskFileItemFactory对象，通过它来解析请求。执行解析后，所有的表单项目都保存在一个List中。
      
ServletFileUpload upload = new ServletFileUpload(factory);
      
List<FileItem> items = upload.parseRequest(request);
      
Iterator<FileItem> itr = items.iterator();
      
while (itr.hasNext()) {
          
FileItem item = (FileItem) itr.next();
          
//检查当前项目是普通表单项目还是上传文件。
          
if (item.isFormField()) {//如果是普通表单项目，显示表单内容。
      
String fieldName = item.getFieldName();
      
if (fieldName.equals("name"))
//对应demo1.html中type="text" name="name"
          
out.print("the field name is" + item.getString());//显示表单内容。
      
out.print("<br>");
          
} else {//如果是上传文件，显示文件名。
      
out.print("the upload file name is" + item.getName());
      
out.print("<br>");
          
}
      
}
   
} else {
      
out.print("the enctype must be multipart/form-data");
   
}
%>
<html>
<head>
   
<meta http-equiv="Content-Type"
content="text/html; charset=GB18030">
   
<title>File upload</title>
</head>
<body>
</body>
</html>
结果：
the field name isjeff
the upload file name isD:\C语言考试样题\作业题.rar
示例2
上传两个文件到指定的目录。
demo2.html
<html>
<head>
   
<meta http-equiv="Content-Type"
content="text/html; charset=GB18030">
   
<title>File upload</title>
</head>
<body>
   
<form name="myform"
action="demo2.jsp"
method="post"
      
enctype="multipart/form-data">
      
File1:<br>
      
<input type="file"
name="myfile"><br>
      
File2:<br>
      
<input type="file"
name="myfile"><br>
      
<br>
      
<input type="submit"
name="submit"
value="Commit">
   
</form>
</body>
</html>
 
demo2.jsp
<%@
page language="java"
contentType="text/html; charset=GB18030"
   
pageEncoding="GB18030"%>
<%@
page import="org.apache.commons.fileupload.*"%>
<%@
page import="org.apache.commons.fileupload.servlet.*"%>
<%@
page import="org.apache.commons.fileupload.disk.*"%>
<%@
page import="java.util.*"%>
<%@
page import="java.io.*"%>
 
<!DOCTYPE
HTML PUBLIC
"-//W3C//DTD HTML 4.01 Transitional//EN">
<%String uploadPath="D:\\temp";
 
boolean isMultipart = ServletFileUpload.isMultipartContent(request);
 
if(isMultipart==true){
   
  try{
   
    FileItemFactory factory = new DiskFileItemFactory();
   
    ServletFileUpload upload = new ServletFileUpload(factory);
   
    List<FileItem> items = upload.parseRequest(request);//得到所有的文件
   
   Iterator<FileItem> itr = items.iterator();
   
    while(itr.hasNext()){//依次处理每个文件
      
  FileItem item=(FileItem)itr.next();
      
  String fileName=item.getName();//获得文件名，包括路径
      
  if(fileName!=null){
          
  File fullFile=new File(item.getName());
          
  File savedFile=new File(uploadPath,fullFile.getName());
          
  item.write(savedFile);
      
  }
   
    }
   
    out.print("upload succeed");
   
  }
   
  catch(Exception e){
      
  e.printStackTrace();
   
  }
 
}
 
else{
   
  out.println("the enctype must be multipart/form-data");
 
}
%>
<html>
<head>
<meta
http-equiv="Content-Type"
content="text/html; charset=GB18030">
<title>File upload</title>
</head>
<body>
</body>
</html>
结果：
upload succeed
此时，在"D:\temp"下可以看到你上传的两个文件。
示例3
上传一个文件到指定的目录，并限定文件大小。
demo3.html
<html>
<head>
   
<meta http-equiv="Content-Type"
content="text/html; charset=GB18030">
   
<title>File upload</title>
</head>
<body>
   
<form name="myform"
action="demo3.jsp"
method="post"
      
enctype="multipart/form-data">
      
File:<br>
      
<input type="file"
name="myfile"><br>
      
<br>
      
<input type="submit"
name="submit"
value="Commit">
   
</form>
</body>
</html>
 
demo3.jsp
<%@
page language="java"
contentType="text/html; charset=GB18030"
   
pageEncoding="GB18030"%>
<%@
page import="org.apache.commons.fileupload.*"%>
<%@
page import="org.apache.commons.fileupload.servlet.*"%>
<%@
page import="org.apache.commons.fileupload.disk.*"%>
<%@
page import="java.util.*"%>
<%@
page import="java.io.*"%>
 
<!DOCTYPE
HTML PUBLIC
"-//W3C//DTD HTML 4.01 Transitional//EN">
<%
   
File uploadPath = new File("D:\\temp");//上传文件目录
   
if (!uploadPath.exists()) {
      
uploadPath.mkdirs();
   
}
   
// 临时文件目录
   
File tempPathFile = new File("d:\\temp\\buffer\\");
   
if (!tempPathFile.exists()) {
      
tempPathFile.mkdirs();
   
}
   
try {
      
// Create a factory for disk-based file items
      
DiskFileItemFactory factory = new DiskFileItemFactory();
 
      
// Set factory constraints
      
factory.setSizeThreshold(4096); // 设置缓冲区大小，这里是4kb
      
factory.setRepository(tempPathFile);//设置缓冲区目录
 
      
// Create a new file upload handler
      
ServletFileUpload upload = new ServletFileUpload(factory);
 
      
// Set overall request size constraint
      
upload.setSizeMax(4194304); // 设置最大文件尺寸，这里是4MB
 
      
List<FileItem> items = upload.parseRequest(request);//得到所有的文件
      
Iterator<FileItem> i = items.iterator();
      
while (i.hasNext()) {
          
FileItem fi = (FileItem) i.next();
          
String fileName = fi.getName();
          
if (fileName !=
null) {
      
File fullFile = new File(fi.getName());
      
File savedFile = new File(uploadPath, fullFile
             
.getName());
      
fi.write(savedFile);
          
}
      
}
      
out.print("upload succeed");
   
} catch (Exception e) {
      
e.printStackTrace();
   
}
%>
<html>
<head>
<meta
http-equiv="Content-Type"
content="text/html; charset=GB18030">
<title>File upload</title>
</head>
<body>
</body>
</html>
示例4
利用Servlet来实现文件上传。
Upload.java
package com.zj.sample;
 
import java.io.File;
import java.io.IOException;
import java.util.Iterator;
import java.util.List;
 
import javax.servlet.ServletException;
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;
 
@SuppressWarnings("serial")
publicclass Upload
extends HttpServlet {
   
private String
uploadPath =
"D:\\temp"; //
上传文件的目录
   
private String
tempPath =
"d:\\temp\\buffer\\";
// 临时文件目录
   
File tempPathFile;
 
   
@SuppressWarnings("unchecked")
   
publicvoid doPost(HttpServletRequest request, HttpServletResponse response)
          
throws IOException, ServletException {
      
try {
          
// Create a factory for disk-based file items
          
DiskFileItemFactory factory = new DiskFileItemFactory();
 
          
// Set factory constraints
          
factory.setSizeThreshold(4096); // 设置缓冲区大小，这里是4kb
          
factory.setRepository(tempPathFile);//
设置缓冲区目录
 
          
// Create a new file upload handler
          
ServletFileUpload upload = new ServletFileUpload(factory);
 
          
// Set overall request size constraint
          
upload.setSizeMax(4194304); // 设置最大文件尺寸，这里是4MB
 
          
List<FileItem> items = upload.parseRequest(request);//
得到所有的文件
          
Iterator<FileItem> i = items.iterator();
          
while (i.hasNext()) {
             
FileItem fi = (FileItem) i.next();
             
String fileName = fi.getName();
             
if (fileName !=
null) {
                 
File fullFile = new File(fi.getName());
                 
File savedFile = new File(uploadPath, fullFile.getName());
                 
fi.write(savedFile);
             
}
          
}
          
System.out.print("upload succeed");
      
} catch (Exception e) {
          
// 可以跳转出错页面
          
e.printStackTrace();
      
}
   
}
 
   
publicvoid init()
throws ServletException {
      
File uploadFile = new File(uploadPath);
      
if (!uploadFile.exists()) {
          
uploadFile.mkdirs();
      
}
      
File tempPathFile = new File(tempPath);
   
    if (!tempPathFile.exists()) {
          
tempPathFile.mkdirs();
      
}
   
}
}
 
demo4.html
<html>
<head>
   
<meta http-equiv="Content-Type"
content="text/html; charset=GB18030">
   
<title>File upload</title>
</head>
<body>
// action="fileupload"对应web.xml中<servlet-mapping>中<url-pattern>的设置.
   
<form name="myform"
action="fileupload"
method="post"
      
enctype="multipart/form-data">
      
File:<br>
      
<input type="file"
name="myfile"><br>
      
<br>
      
<input type="submit"
name="submit"
value="Commit">
   
</form>
</body>
</html>
 
web.xml
<servlet>
   
<servlet-name>Upload</servlet-name>
   
<servlet-class>com.zj.sample.Upload</servlet-class>
</servlet>
 
<servlet-mapping>
   
<servlet-name>Upload</servlet-name>
   
<url-pattern>/fileupload</url-pattern>
</servlet-mapping>

2 下面说下JQUERY上传：

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