学步园

就在前段时间，还在苦于找到不到合适的上传组件，虽然很早就知道了 common-fileupload，但当时却因为没有找到如何获取表单参数的方法而使用 jspSmartUpload，历尽艰辛终于找到了它的 jar，可是使用后才发现此东西对中文参数支持奇差，甚至需要修改源代码才能解决问题，可是jspSmartUpload并不是开源的项目，而且开发团队也不再对它进行更新，连官方网站都关门大吉了，情急之下使用JadClipse 反编译了它的jar包，原以为问题算是得到解决了，谁知道后来却发现获取到的参数经常出现部分中文乱码，而且还不是固定的汉字出现乱码，仔细研究加Google后才找出了规律，原来是奇数字数的中文会出现乱码，而偶数字数的则正常，阅读了源代码，终于还是没耐心阅读下去，而且看到网上还有评论说该组件有内存泄露的问题，于是才下定决定搞定common-fileupload。

于是从 http://jakarta.apache.org/commons/fileupload/ 下载到了最新版的 FileUpload 1.2，阅读了部分文档跟例子，终于找到了获取表单中参数的方法并对该组件做了进一点封装，使其更容易使用，并支持单文件上传和多文件上传两种方式，首先定义一个基类放置公共属性：

FileUploadBase.java

import java.io.File;
import java.util.HashMap;
import java.util.Map;

import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;

publicabstractclass FileUploadBase {
protected Map<String, String> parameters =new HashMap<String, String>();// 保存普通form表单域

protected String encoding ="utf-8"; // 字符编码，当读取上传表单的各部分时会用到该encoding

protected UploadFileFilter filter =null; // 文件过滤器, 默认为NULL 不过滤

/** *//**
* The directory in which uploaded files will be stored, if stored on disk.
*/
protectedint sizeThreshold = DiskFileItemFactory.DEFAULT_SIZE_THRESHOLD;

/** *//**
*
* The maximum size permitted for the complete request, as opposed to
*
* {@link #fileSizeMax}. A value of -1 indicates no maximum.
*
*/
protectedlong sizeMax =-1;

/** *//**
* The directory in which uploaded files will be stored, if stored on disk.
*/
protected File repository;

public String getParameter(String key) {
return parameters.get(key);
}

public String getEncoding() {
return encoding;
}

publicvoid setEncoding(String encoding) {
this.encoding = encoding;
}

/** *//**
* 获取上传文件最大的大小，单位为Byte(字节），为-1时表示无限制
* @return
*/
publiclong getSizeMax() {
return sizeMax;
}

/** *//**
* 设置上传文件最大的大小，单位为Byte(字节），为-1时表示无限制
* @param sizeMax
*/
publicvoid setSizeMax(long sizeMax) {
this.sizeMax = sizeMax;
}

publicint getSizeThreshold() {
return sizeThreshold;
}

publicvoid setSizeThreshold(int sizeThreshold) {
this.sizeThreshold = sizeThreshold;
}

/** *//**
* Returns the directory used to temporarily store files that are larger
* than the configured size threshold.
*
* @return The directory in which temporary files will be located.
*
* @see #setRepository(java.io.File)
*
*/
public File getRepository() {
return repository;
}

/** *//**
* Sets the directory used to temporarily store files that are larger than
* the configured size threshold.
*
* @param repository
* The directory in which temporary files will be located.
*
* @see #getRepository()
*
*/
publicvoid setRepository(File repository) {
this.repository = repository;
}

/** *//**
* 获取参数列表
* @return
*/
public Map<String, String> getParameters() {
return parameters;
}

/** *//**
* 获取过滤器
* @return
*/
public UploadFileFilter getFilter() {
return filter;
}

/** *//**
* 设置文件过滤器，不符合过滤器规则的将不被上传
* @param filter
*/
publicvoid setFilter(UploadFileFilter filter) {
this.filter = filter;
}

/** *//**
* 验证文件是否有效
* @param item
* @return
*/
protectedboolean isValidFile(FileItem item){
return item ==null|| item.getName() ==""|| item.getSize() ==0|| (filter !=null&&!filter.accept(item.getName())) ?false : true;
}
}

支持单文件上传的 SingleFileUpload 类：
SingleFileUpload.java

import java.io.File;
import java.io.UnsupportedEncodingException;
import java.util.List;

import javax.servlet.http.HttpServletRequest;

import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;

publicclass SingleFileUpload extends FileUploadBase {
private FileItem fileItem;

/** *//**
*
* @param request
* @throws UnsupportedEncodingException
*/
publicvoid parseRequest(HttpServletRequest request)
throws UnsupportedEncodingException {

DiskFileItemFactory factory =new DiskFileItemFactory();

factory.setSizeThreshold(sizeThreshold);

if (repository !=null)
factory.setRepository(repository);

ServletFileUpload upload =new ServletFileUpload(factory);

upload.setHeaderEncoding(encoding);

try{
List<FileItem> items = upload.parseRequest(request);

for (FileItem item : items) {
if (item.isFormField()) {
String fieldName = item.getFieldName();
String value = item.getString(encoding);
parameters.put(fieldName, value);
}else{

if (!super.isValidFile(item)) {
continue;
}

if (fileItem ==null)
fileItem = item;
}
}

}catch (FileUploadException e) {
e.printStackTrace();
}
}

/** *//**
* 上传文件, 调用该方法之前必须先调用 parseRequest(HttpServletRequest request)
* @param fileName 完整文件路径
* @throws Exception
*/
publicvoid upload(String fileName) throws Exception {
File file =new File(fileName);
uploadFile(file);
}

/** *//**
* 上传文件, 调用该方法之前必须先调用 parseRequest(HttpServletRequest request)
* @param parent 存储的目录
* @throws Exception
*/
publicvoid upload(File parent) throws Exception {
if (fileItem ==null)
return;

String name = fileItem.getName();
File file =new File(parent, name);
uploadFile(file);
}

privatevoid uploadFile(File file) throws Exception{
if (fileItem ==null)
return;

long fileSize = fileItem.getSize();
if (sizeMax >-1&& fileSize >super.sizeMax){
String message = String.format("the request was rejected because its size (%1$s) exceeds the configured maximum (%2$s)", fileSize, super.sizeMax);

thrownew org.apache.commons.fileupload.FileUploadBase.SizeLimitExceededException(message, fileSize, super.sizeMax);
}

String name = fileItem.getName();
fileItem.write(file);
}

/** */