java组件commons-fileupload实现文件上传
一、所需要的包：
1、commons-fileupload-1.2.1.jar：
下载地址
http://commons.apache.org/downloads/download_fileupload.cgi
2、commons-io-1.4.jar：
下载地址
http://commons.apache.org/downloads/download_io.cgi
二、注意事项：
form表单里面要加上enctype="multipart/form-data"
三、代码示例
1、jsp代码：
<%@pagelanguage="java"contentType="text/html;charset=UTF-8" pageEncoding="UTF-8"%> <!DOCTYPEhtmlPUBLIC"-//W3C//DTDHTML4.01Transitional//EN""http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <metahttp-equiv="Content-Type"content="text/html;charset=utf-8"> <title>upload</title> </head> <body> <formaction="uploadServlet"method="post"enctype="multipart/form-data"> <table> <caption>上传实例</caption> <tr> <td>姓名</td> <td> <inputtype="text"name="name"> </td> </tr> <tr> <td>年龄</td> <td> <inputtype="text"name="age"> </td> </tr> <tr> <td>照片</td> <td> <inputtype="file"name="image"> </td> </tr> <tr> <td></td> <td> <inputtype="submit"value="提交"> </td> </tr> </table> </form> </body> </html>
2、UploadServlet代码
packageservlet;
importjava.io.BufferedInputStream;
importjava.io.BufferedOutputStream;
importjava.io.File;
importjava.io.FileOutputStream;
importjava.io.IOException;
importjava.io.Writer;
importjava.util.Iterator;
importjava.util.List;
importjavax.servlet.ServletException;
importjavax.servlet.http.HttpServlet;
importjavax.servlet.http.HttpServletRequest;
importjavax.servlet.http.HttpServletResponse;
importorg.apache.commons.fileupload.FileItem;
importorg.apache.commons.fileupload.FileUploadException;
importorg.apache.commons.fileupload.FileUploadBase.SizeLimitExceededException;
importorg.apache.commons.fileupload.disk.DiskFileItemFactory;
importorg.apache.commons.fileupload.servlet.ServletFileUpload;
importorg.apache.commons.fileupload.util.Streams;
/**
*上传servlet
*@authorlisanlai
*
*/
publicclassUploadServletextendsHttpServlet{
privatestaticfinallongserialVersionUID=1L;
publicUploadServlet(){
super();
}
protectedvoiddoGet(HttpServletRequestrequest,HttpServletResponseresponse)throwsServletException,IOException{
this.doPost(request,response);
}
@SuppressWarnings("unchecked")
protectedvoiddoPost(HttpServletRequestrequest,HttpServletResponseresponse)throwsServletException,IOException{
response.setContentType("text/html");
//设置字符编码为UTF-8,这样支持汉字显示
response.setCharacterEncoding("UTF-8");
Writero=response.getWriter();
/**
*首先判断form的enctype是不是multipart/form-data
*同时也判断了form的提交方式是不是post
*方法：isMultipartContent(request)
*/
if(ServletFileUpload.isMultipartContent(request)){
request.setCharacterEncoding("utf-8");
//实例化一个硬盘文件工厂,用来配置上传组件ServletFileUpload
DiskFileItemFactoryfactory=newDiskFileItemFactory();
//设置文件存放的临时文件夹，这个文件夹要真实存在
FilefileDir=newFile("../webapps/fileupload/tmp/");
if(fileDir.isDirectory()&&fileDir.exists()==false){
fileDir.mkdir();
}
factory.setRepository(fileDir);
//设置最大占用的内存
factory.setSizeThreshold(1024000);
//创建ServletFileUpload对象
ServletFileUploadsfu=newServletFileUpload(factory);
sfu.setHeaderEncoding("utf-8");
//设置单个文件最大值byte
sfu.setFileSizeMax(102400000);
//所有上传文件的总和最大值byte
sfu.setSizeMax(204800000);
List<FileItem>items=null;
try{
items=sfu.parseRequest(request);
}catch(SizeLimitExceededExceptione){
System.out.println("文件大小超过了最大值");
}catch(FileUploadExceptione){
e.printStackTrace();
}
//取得items的迭代器
Iterator<FileItem>iter=items==null?null:items.iterator();
//图片上传后存放的路径目录
Fileimages=newFile("D:/upload/images/");
if(images.exists()==false){
images.mkdirs();
}
//迭代items
while(iter!=null&&iter.hasNext()){
FileItemitem=(FileItem)iter.next();
//如果传过来的是普通的表单域
if(item.isFormField()){
System.out.print("普通的表单域:");
System.out.print(newString(item.getFieldName())+"");
System.out.println(newString(item.getString("UTF-8")));
}
//文件域
elseif(!item.isFormField()){
System.out.println("源图片:"+item.getName());
StringfileName=item.getName().substring(item.getName().lastIndexOf("\\"));
BufferedInputStreamin=newBufferedInputStream(item.getInputStream());
//文件存储在D:/upload/images目录下,这个目录也得存在
BufferedOutputStreamout=newBufferedOutputStream(
newFileOutputStream(newFile(images.getAbsolutePath()+fileName)));
Streams.copy(in,out,true);
o.write("文件上传成功");
}
}
}else{
System.out.println("表单的enctype类型错误");
}
}
}
3、web.xml
<?xmlversion="1.0"encoding="UTF-8"?> <web-appxmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xmlns="http://java.sun.com/xml/ns/javaee"xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"xsi:schemaLocation="http://java.sun.com/xml/ns/javaeehttp://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"id="WebApp_ID"version="2.5"> <display-name>UploadTest</display-name> <welcome-file-list> <welcome-file>upload.jsp</welcome-file> </welcome-file-list> <servlet> <description></description> <display-name>UploadServlet</display-name> <servlet-name>UploadServlet</servlet-name> <servlet-class>servlet.UploadServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>UploadServlet</servlet-name> <url-pattern>/uploadServlet</url-pattern> </servlet-mapping> </web-app>
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