用fileupload组件实现的大文件上传简单实例
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2022-06-29 13:18:23
1.fileuploadservlet.java文件，实现上传处理
import java.io.file;
import java.io.ioexceptio...
1.fileuploadservlet.java文件，实现上传处理
import java.io.file;
import java.io.ioexception;
import java.io.printwriter;
import java.text.decimalformat;
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.fileuploadexception;
import org.apache.commons.fileupload.fileuploadbase.sizelimitexceededexception;
import org.apache.commons.fileupload.disk.diskfileitemfactory;
import org.apache.commons.fileupload.servlet.servletfileupload;
public class fileuploadservlet extends httpservlet
{
private static final long serialversionuid = 1l;
public fileuploadservlet()
{
super();
}
protected void doget(httpservletrequest request,
httpservletresponse response) throws servletexception, ioexception
{
this.dopost(request, response);
}
protected void dopost(httpservletrequest request,
httpservletresponse response) throws servletexception, ioexception
{
final long max_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
final string[] allowedext = new string[]
{ "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
diskfileitemfactory dfif = new diskfileitemfactory();
// 用以上工厂实例化上传组件
servletfileupload sfu = new servletfileupload(dfif);
// 设置最大上传大小
sfu.setsizemax(max_size);
printwriter out = response.getwriter();
// 从request得到所有上传域的列表
list filelist = null;
try
{
filelist = sfu.parserequest(request);
} catch (fileuploadexception e)
{// 处理文件尺寸过大异常
if (e instanceof sizelimitexceededexception)
{
out.println("文件尺寸超过规定大小:" + max_size + "字节<p />");
out.println("<a href=\"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("<a href=\"fileupload.html\" target=\"_top\">返回</a>");
return;
}
//文件大小取两位小数
decimalformat digit=new decimalformat("0.00");
// 得到所有上传的文件
iterator fileitr = filelist.iterator();
// 循环处理所有文件
while (fileitr.hasnext())
{
fileitem fileitem = null;
string path = null;
double size = 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(<input type="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("<a href=\"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
string t_name = path.substring(path.lastindexof("\\") + 1);
// 得到文件的扩展名(无扩展名时将得到全名)
string t_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
int allowflag = 0;
int allowedextcount = 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]
+ " ");
out.println("<p /><a href=\"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(new file("\\"+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("<a href=\"fileupload.html\" target=\"_top\">继续上传</a>");
out.println("</html>");
} catch (exception e)
{
e.printstacktrace();
}
}
}
}
2.fileupload.html文件，实现上传页面。
<html> <head> <meta http-equiv="content-type" content="text/html; charset=utf-8"> <title>文件上传</title> </head> <body> <form action="fileuploadservlet" method="post" enctype="multipart/form-data"> <input type="file" size="30" name="file01" /><br> <pre> <input name="submit" type="submit" value="上传"> <input name="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。
<?xml version="1.0" encoding="utf-8"?> <web-app version="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/j2ee http://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
package com.xulu;
import java.io.ioexception;
import javax.servlet.*;
import javax.servlet.http.httpservletrequest;
import javax.servlet.http.httpservletresponse;
public class encodingchange implements filter
{
protected string encoding = null;
protected filterconfig filterconfig = null;
protected boolean ignore = true;
public void destroy()
{
this.encoding = null;
this.filterconfig = null;
}
public void dofilter(servletrequest requests, servletresponse responses,
filterchain chain) throws ioexception, servletexception
{
// todo auto-generated method stub
httpservletrequest request = (httpservletrequest) requests;
httpservletresponse response = (httpservletresponse) responses;
if (ignore || request.getcharacterencoding() == null)
{
string encoding = 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);
}
public void init(filterconfig filterconfig) throws servletexception
{
// todo auto-generated method stub
this.filterconfig = filterconfig;
this.encoding = filterconfig.getinitparameter("encoding");
string value = filterconfig.getinitparameter("ignore");
if (value == null)
{
this.ignore = true;
} else if (value.equalsignorecase("true"))
{
this.ignore = true;
} else if (value.equalsignorecase("yes"))
{
this.ignore = true;
} else
{
this.ignore = false;
}
}
public string selectencoding(servletrequest request)
{
return this.encoding;
}
}
和
package com.xulu;
import java.io.ioexception;
import javax.servlet.*;
import javax.servlet.http.httpservletrequest;
import javax.servlet.http.httpservletresponse;
public class setcharacterencoding implements filter{
protected string encoding=null;
protected filterconfig filterconfig=null;
protected boolean ignore=true;
public void destroy() {
this.encoding=null;
this.filterconfig=null;
}
public void dofilter(servletrequest requests, servletresponse responses,
filterchain chain) throws ioexception, servletexception {
// todo auto-generated method stub
httpservletrequest request=(httpservletrequest)requests;
httpservletresponse response=(httpservletresponse)responses;
if(ignore||request.getcharacterencoding()==null){
string encoding=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);
}
public void init(filterconfig filterconfig) throws servletexception {
// todo auto-generated method stub
this.filterconfig = filterconfig;
this.encoding = filterconfig.getinitparameter("encoding");
string value = filterconfig.getinitparameter("ignore");
if (value == null) {
this.ignore = true;
} else if (value.equalsignorecase("true")) {
this.ignore = true;
} else if (value.equalsignorecase("yes")) {
this.ignore = true;
} else {
this.ignore = false;
}
}
public string selectencoding(servletrequest request){
return this.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~