commonsfileupload实现文件上传的实例代码

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>











name:

file1:

file2:

package com.itheima.servlet;
import java.io.File;
import java.io.IOException;
import java.io.PrintWriter;
import java.io.UnsupportedEncodingException;
import java.util.List;
import java.util.UUID;
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.FileUploadBase;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
import org.apache.commons.io.FilenameUtils;
//详解
public class UploadServlet3 extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
request.setCharacterEncoding("UTF-8");
response.setContentType("text/html;charset=UTF-8");
PrintWriter out = response.getWriter();
System.out.print(request.getRemoteAddr());
boolean isMultipart = ServletFileUpload.isMultipartContent(request);
if(!isMultipart){
throw new RuntimeException("请检查您的表单的enctype属性，确定是multipart/form-data");
}
DiskFileItemFactory dfif = new DiskFileItemFactory();
ServletFileUpload parser = new ServletFileUpload(dfif);
// parser.setFileSizeMax(3*1024*1024);//设置单个文件上传的大小
// parser.setSizeMax(6*1024*1024);//多文件上传时总大小限制
List items = null;
try {
items = parser.parseRequest(request);
}catch(FileUploadBase.FileSizeLimitExceededException e) {
out.write("上传文件超出了3M");
return;
}catch(FileUploadBase.SizeLimitExceededException e){
out.write("总文件超出了6M");
return;
}catch (FileUploadException e) {
e.printStackTrace();
throw new RuntimeException("解析上传内容失败，请重新试一下");
}
//处理请求内容
if(items!=null){
for(FileItem item:items){
if(item.isFormField()){
processFormField(item);
}else{
processUploadField(item);
}
}
}
out.write("上传成功！");
}
private void processUploadField(FileItem item) {
try {
String fileName = item.getName();
//用户没有选择上传文件时
if(fileName!=null&&!fileName.equals("")){
fileName = UUID.randomUUID().toString()+"_"+FilenameUtils.getName(fileName);
//扩展名
String extension = FilenameUtils.getExtension(fileName);
//MIME类型
String cOntentType= item.getContentType();
if(contentType.startsWith("image/")){
//分目录存储：日期解决
// Date now = new Date();
// DateFormat df = new SimpleDateFormat("yyyy-MM-dd");
// 
// String childDirectory = df.format(now);
//按照文件名的hashCode计算存储目录
String childDirectory = makeChildDirectory(getServletContext().getRealPath("/WEB-INF/files/"),fileName);
String storeDirectoryPath = getServletContext().getRealPath("/WEB-INF/files/"+childDirectory);
File storeDirectory = new File(storeDirectoryPath);
if(!storeDirectory.exists()){
storeDirectory.mkdirs();
}
System.out.println(fileName);
item.write(new File(storeDirectoryPath+File.separator+fileName));//删除临时文件
}
}
} catch (Exception e) {
throw new RuntimeException("上传失败,请重试");
}
}
//计算存放的子目录
private String makeChildDirectory(String realPath, String fileName) {
int hashCode = fileName.hashCode();
int dir1 = hashCode&0xf;// 取1~4位
int dir2 = (hashCode&0xf0)>>4;//取5~8位
String directory = ""+dir1+File.separator+dir2;
File file = new File(realPath,directory);
if(!file.exists())
file.mkdirs();
return directory;
}
private void processFormField(FileItem item) {
String fieldName = item.getFieldName();//字段名
String fieldValue;
try {
fieldValue = item.getString("UTF-8");
} catch (UnsupportedEncodingException e) {
throw new RuntimeException("不支持UTF-8编码");
}
System.out.println(fieldName+"="+fieldValue);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}