用Jakarta commons fileupload组件实现多文件上传(demo)_jakarta diskfileitemfactory factory-优快云博客

在上一篇文章《利用Jakarta commons fileupload组件实现多文件上传》中，我介绍了commons fileupload组件的基本原理和实现方法。但是在实际操作中，我们需要分析每个FileItem，然后从该FileItem中读取该控件的name和value，显然这不符合我们的习惯。比如我们在页面上有个text文本框：

< input type ="text" name ="possess" >

我们要取得possess传过来的value，一般我们是这么写的：

String possess = request.getParameter( " possess " )

但是在commons fileupload中我们却需要这么处理：

DiskFileItemFactory factory = new DiskFileItemFactory();

// Create a new file upload handler

ServletFileUpload upload = new ServletFileUpload(factory);

String possess = "" ;

try {

List items = upload.parseRequest(request);

Iterator iterator = items.iterator();

while(iterator.hasNext()){

FileItem item = (FileItem)iterator.next();

if(item.isFormField()){

String fieldName = item.getFieldName();

String value = item.getString();

if(fieldName.equals("possess")){

possess = value;

}

} catch (FileUploadException e) {

e.printStackTrace();

}

按照上面处理的话，很是不爽，因此我想包装一下，使得使用起来符合我们的习惯。
总体设计思想：

1.我们可以像以前那样，传入控件的name，就可以取得该控件的value，因此我想可以遍历所有FileItem，然后把他们存入一个Map中(key中存入fieldname，value中存入该控件的value)，这样就可以达到以上目的了。
2.在该包装类中，我们还要可以设置一些值，从而我们可以更改commons fileupload中的一些配置。

具体实现：
根据以上要求，我写出了一个MutiFileUpload类，代码如下，稍后再做详细解释。

package chb.commons.fileupload.web;

import java.util.HashMap;

import java.util.Iterator;

import java.util.List;

import java.util.Map;

import javax.servlet.http.HttpServlet;

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;

/**

* @author chb

public class MutiFileUpload extends HttpServlet {

private static final long serialVersionUID = 670829239023754119L;

protected Map<String, String> parameters;//保存普通form表单域

protected Map<String, FileItem> files;//保存上传的文件

/**

* The directory in which uploaded files will be stored, if stored on disk.

private int 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.

private long sizeMax = -1;

private 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

public String getEncoding() {

return encoding;

}

public void setEncoding(String encoding) {

this.encoding = encoding;

}

public long getSizeMax() {

return sizeMax;

}

public void setSizeMax(long sizeMax) {

this.sizeMax = sizeMax;

}

public int getSizeThreshold() {

return sizeThreshold;

}

public void setSizeThreshold(int sizeThreshold) {

this.sizeThreshold = sizeThreshold;

}

public void parse(HttpServletRequest request){

parameters = new HashMap<String, String>();

files = new HashMap<String, FileItem>();

//Create a factory for disk-based file items

DiskFileItemFactory factory = new DiskFileItemFactory();

//Set factory constraints

factory.setSizeThreshold(sizeThreshold);

//factory.setRepository(repository);

//Create a new file upload handler

ServletFileUpload upload = new ServletFileUpload(factory);

//Set overall request size constraint

upload.setSizeMax(sizeMax);

upload.setHeaderEncoding(encoding);

try {

List items = upload.parseRequest(request);

Iterator iterator = items.iterator();

while(iterator.hasNext()){

FileItem item = (FileItem)iterator.next();

if(item.isFormField()){

String fieldName = item.getFieldName();

String value = item.getString();

parameters.put(fieldName, value);

}else{

String fieldName = item.getFieldName();

files.put(fieldName, item);

}

} catch (FileUploadException e) {

e.printStackTrace();

}

/** 得到上传文件的文件名

* @param item

* @return

public String getFileName(FileItem item){

String fileName = item.getName();

fileName = replace(fileName,"/","/");

fileName = fileName.substring(fileName.lastIndexOf("/")+1);

return fileName;

}

/**字符串替换

* @param source

* @param oldString

* @param newString

* @return

public static String replace(String source, String oldString, String newString) {

StringBuffer output = new StringBuffer();

int lengthOfSource = source.length();

int lengthOfOld = oldString.length();

int posStart = 0;

int pos;

while ((pos = source.indexOf(oldString, posStart)) >= 0) {

output.append(source.substring(posStart, pos));

output.append(newString);

posStart = pos + lengthOfOld;

}

if (posStart < lengthOfSource) {

output.append(source.substring(posStart));

}

return output.toString();

}

         以上代码很简单，看过commons FileUpload组件API的程序员，应该都能看明白。值得注意一下的是：编码问题（setHeaderEncoding），这个方法是从 FileUploadBase类里继承的，根据其说明，当读取上传表单的各部分时会用到该encoding，如果没有指定encoding则使用系统缺省的encoding。建议在这里设置成utf-8，并把jsp的charset也设置成utf-8，否则可能会出现乱码。
测试demo
        好了，下面我就写个简单的demo吧，说明一下MutiFileUpload的用法。
       1.新建一个jsp页面，注意设置form表单的enctype，如下：