用fileupload组件实现的大文件上传简单实例

2024-03-11 21:38:03 142

1.FileUploadServlet.java文件，实现上传处理

importjava.io.File;
importjava.io.IOException;
importjava.io.PrintWriter;
importjava.text.DecimalFormat;
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;

publicclassFileUploadServletextendsHttpServlet
{
privatestaticfinallongserialVersionUID=1L;

publicFileUploadServlet()
{
super();
}

protectedvoiddoGet(HttpServletRequestrequest,
HttpServletResponseresponse)throwsServletException,IOException
{
this.doPost(request,response);
}

protectedvoiddoPost(HttpServletRequestrequest,
HttpServletResponseresponse)throwsServletException,IOException
{

finallongMAX_SIZE=2048*1024*1024;//设置上传文件最大值为2G，可以改为更大
//允许上传的文件格式的列表
finalString[]allowedExt=newString[]
{"exe","jpg","DT"};
response.setContentType("text/html");
//设置字符编码为UTF-8,统一编码，处理出现乱码问题
response.setCharacterEncoding("UTF-8");

//实例化一个硬盘文件工厂,用来配置上传组件ServletFileUpload
DiskFileItemFactorydfif=newDiskFileItemFactory();

//用以上工厂实例化上传组件
ServletFileUploadsfu=newServletFileUpload(dfif);
//设置最大上传大小
sfu.setSizeMax(MAX_SIZE);

PrintWriterout=response.getWriter();
//从request得到所有上传域的列表
ListfileList=null;
try
{
fileList=sfu.parseRequest(request);
}catch(FileUploadExceptione)
{//处理文件尺寸过大异常
if(einstanceofSizeLimitExceededException)
{
out.println("文件尺寸超过规定大小:"+MAX_SIZE+"字节<p/>");
out.println("<ahref=\"FileUpload.html\"target=\"_top\">返回</a>");
return;
}
e.printStackTrace();
}
//没有文件上传
if(fileList==null||fileList.size()==0)
{
out.println("请选择上传文件<p/>");
out.println("<ahref=\"FileUpload.html\"target=\"_top\">返回</a>");
return;
}
//文件大小取两位小数
DecimalFormatdigit=newDecimalFormat("0.00");
//得到所有上传的文件
IteratorfileItr=fileList.iterator();
//循环处理所有文件
while(fileItr.hasNext())
{
FileItemfileItem=null;
Stringpath=null;
doublesize=0;
//得到当前文件
fileItem=(FileItem)fileItr.next();
//忽略简单form字段而不是上传域的文件域(<inputtype="text"/>等)
if(fileItem==null||fileItem.isFormField())
{
continue;
}

//得到文件的大小，K为单位并保留两位小数
size=(double)fileItem.getSize()/1024;
if("".equals(path)||size==0)
{
out.println("<html><head><title>上传处理界面</title></head>");
out.println("请选择上传文件<p/>");
out.println("<ahref=\"FileUpload.html\"target=\"_top\">返回</a>");
out.println("</html>");
return;
}
//得到文件的完整路径
path=fileItem.getName();

//得到去除路径的文件名
Stringt_name=path.substring(path.lastIndexOf("\\")+1);
//得到文件的扩展名(无扩展名时将得到全名)
Stringt_ext=t_name.substring(t_name.lastIndexOf(".")+1);
//拒绝接受规定文件格式之外的文件类型
intallowFlag=0;
intallowedExtCount=allowedExt.length;
for(;allowFlag<allowedExtCount;allowFlag++)
{
if(allowedExt[allowFlag].equals(t_ext))
break;
}
if(allowFlag==allowedExtCount)
{
out.println("<html><head><title>上传处理界面</title></head>");
out.println("请上传以下类型的文件<p/>");
for(allowFlag=0;allowFlag<allowedExtCount;allowFlag++)
out.println("*."+allowedExt[allowFlag]
+"&nbsp;&nbsp;&nbsp;");
out.println("<p/><ahref=\"FileUpload.html\"target=\"_top\">返回</a>");
out.println("</html>");
return;
}
try
{
//保存文件到服务器根目录下
fileItem.write(newFile("\\"+t_name));
System.out.println(t_name);
out.println("<html><head><title>上传处理界面</title></head>");
out.println("文件名称为："+path+"<br>");
out.println("文件上传成功，已保存为:"+t_name
+"<br>"+"文件大小:"+digit.format(size)+"K<p/>");
out.println("<ahref=\"FileUpload.html\"target=\"_top\">继续上传</a>");
out.println("</html>");
}catch(Exceptione)
{
e.printStackTrace();
}
}
}
}

2.FileUpload.html文件，实现上传页面。

<html>
<head>
<metahttp-equiv="Content-Type"content="text/html;charset=UTF-8">
<title>文件上传</title>
</head>
<body>
<formaction="FileUploadServlet"method="post"
enctype="multipart/form-data">
<inputtype="file"size="30"
name="file01"/><br>
<pre><inputname="submit"type="submit"value="上传"><inputname="reset"type="reset"value="重置">
</pre>
</form>
</body>
</html>

3.配置web.xml文件中的的servlet和过滤器，过滤器解决上传文件名为中文时出现乱码。

<?xmlversion="1.0"encoding="UTF-8"?>
<web-appversion="2.4"xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2eehttp://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
<servlet>
<display-name>FileUploadServlet</display-name>
<servlet-name>FileUploadServlet</servlet-name>
<servlet-class>FileUploadServlet</servlet-class>
</servlet>

<servlet-mapping>
<servlet-name>FileUploadServlet</servlet-name>
<url-pattern>/FileUploadServlet</url-pattern>
</servlet-mapping>

<filter>
<filter-name>setCharacterEncoding</filter-name>
<filter-class>com.xulu.EncodingChange</filter-class>
<init-param>
<param-name>ignore</param-name>
<param-value>true</param-value>
</init-param>

<init-param>
<param-name>encoding</param-name>
<param-value>UTF-8</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>setCharacterEncoding</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
<login-config>
<auth-method>BASIC</auth-method>
</login-config>
</web-app>

4.过滤器文件EncodingChange.java和setCharacterEncoding.java分别如下，并且在根目录下的WEB-INF\classes\com\xulu文件夹中放入他它们编译生成的.class文件

packagecom.xulu;

importjava.io.IOException;

importjavax.servlet.*;
importjavax.servlet.http.HttpServletRequest;
importjavax.servlet.http.HttpServletResponse;

publicclassEncodingChangeimplementsFilter
{
protectedStringencoding=null;
protectedFilterConfigfilterconfig=null;
protectedbooleanignore=true;

publicvoiddestroy()
{
this.encoding=null;
this.filterconfig=null;
}

publicvoiddoFilter(ServletRequestrequests,ServletResponseresponses,
FilterChainchain)throwsIOException,ServletException
{
//TODOAuto-generatedmethodstub
HttpServletRequestrequest=(HttpServletRequest)requests;
HttpServletResponseresponse=(HttpServletResponse)responses;
if(ignore||request.getCharacterEncoding()==null)
{
Stringencoding=selectEncoding(request);
if(encoding!=null)
{
request.setCharacterEncoding(encoding);
request.getSession().getAttribute("Login_Student");
request.getSession().getAttribute("Login_Teacher");
request.getSession().getAttribute("Login_Admin");
}
}
chain.doFilter(request,response);
}

publicvoidinit(FilterConfigfilterconfig)throwsServletException
{
//TODOAuto-generatedmethodstub
this.filterconfig=filterconfig;
this.encoding=filterconfig.getInitParameter("encoding");
Stringvalue=filterconfig.getInitParameter("ignore");
if(value==null)
{
this.ignore=true;
}elseif(value.equalsIgnoreCase("true"))
{
this.ignore=true;
}elseif(value.equalsIgnoreCase("yes"))
{
this.ignore=true;
}else
{
this.ignore=false;
}
}

publicStringselectEncoding(ServletRequestrequest)
{
returnthis.encoding;
}
}
和
packagecom.xulu;

importjava.io.IOException;

importjavax.servlet.*;
importjavax.servlet.http.HttpServletRequest;
importjavax.servlet.http.HttpServletResponse;

publicclasssetCharacterEncodingimplementsFilter{
protectedStringencoding=null;
protectedFilterConfigfilterconfig=null;
protectedbooleanignore=true;


publicvoiddestroy(){
this.encoding=null;
this.filterconfig=null;
}

publicvoiddoFilter(ServletRequestrequests,ServletResponseresponses,
FilterChainchain)throwsIOException,ServletException{
//TODOAuto-generatedmethodstub
HttpServletRequestrequest=(HttpServletRequest)requests;
HttpServletResponseresponse=(HttpServletResponse)responses;
if(ignore||request.getCharacterEncoding()==null){
Stringencoding=selectEncoding(request);
if(encoding!=null){
request.setCharacterEncoding(encoding);
request.getSession().getAttribute("Login_Student");
request.getSession().getAttribute("Login_Teacher");
request.getSession().getAttribute("Login_Admin");
}
}
chain.doFilter(request,response);
}

publicvoidinit(FilterConfigfilterconfig)throwsServletException{
//TODOAuto-generatedmethodstub
this.filterconfig=filterconfig;
this.encoding=filterconfig.getInitParameter("encoding");
Stringvalue=filterconfig.getInitParameter("ignore");
if(value==null){
this.ignore=true;
}elseif(value.equalsIgnoreCase("true")){
this.ignore=true;
}elseif(value.equalsIgnoreCase("yes")){
this.ignore=true;
}else{
this.ignore=false;
}
}
publicStringselectEncoding(ServletRequestrequest){
returnthis.encoding;
}
}

5.在浏览器中就可以实现页面的上传了，访问http://localhost:8080/**/FileUpload.html就可以了。其中**为自己命名的web文件夹，如DoUpload，上面的文件都在该目录里，且DoUpload文件夹放在Tomcat的webapp文件夹下。

补充：在上述所有步骤之前需引入三个.jar文件，分别为commons-fileupload-1.2.1.jar，commons-io-1.4.jar和servlet-api.jar网上可以下载到

以上就是小编为大家带来的用fileupload组件实现的大文件上传简单实例的全部内容了，希望对大家有所帮助，多多支持毛票票~

用fileupload组件实现的大文件上传简单实例

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