uploaddownfile.java

一个网上购书系统

/**
 * 
 */
package com.bookstore.util;

import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.net.URL;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.Hashtable;
import java.util.StringTokenizer;

import javax.servlet.ServletException;
import javax.servlet.ServletInputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * 调用方法:
 *Upload up = new Upload();
 *up.init(request);


 *此处可以调用setSaveDir(String saveDir);设置保存路径
 *调用setMaxFileSize(long size)设置上传文件的最大字�?.
 *调用setTagFileName(String)设置上传后文件的名字(只对第一个文件有�?)

 *up. uploadFile();

 *然后String[] names = up.getFileName();得到上传的文件名,文件绝对路径应该�?
 *保存的目录saveDir+"/"+names[i];
 *可以通过up.getParameter("field");得到上传的文本或up.getParameterValues("filed")
 *得到同名字段如多个checkBox的�??.
 *其它的自己试�?.

 * 
 */
public class UploadDownFile {

	private String saveDir = "."; // 要保存文件的路径

	private String charset = ""; // 字符�?

	private ArrayList tmpFileName = new ArrayList(); // 临时存放文件名的数据结构

	private Hashtable parameter = new Hashtable(); // 存放参数名和值的数据结构

	private HttpServletRequest request; // 用于传入请求对象的实�?

	private String boundary = ""; // 内存数据的分隔符

	private int len = 0; // 每次从内在中实际读到的字节长�?

	private String queryString;

	private int count; // 上载的文件�?�数

	private String[] fileName; // 上载的文件名数组

	private long maxFileSize = 1024 * 1024 * 10; // �?大文件上载字�?,默认10M;

	private String tagFileName = "";

	public final void init(HttpServletRequest request) throws ServletException {
		this.request = request;
		boundary = request.getContentType().substring(30); // 得到内存中数据分界符
		queryString = request.getQueryString();
	}

	public String getParameter(String s) { // 用于得到指定字段的参数�??,重写request.getParameter(String
											// s)
		if (parameter.isEmpty()) {
			return null;
		}
		return (String) parameter.get(s);
	}

	public String[] getParameterValues(String s) { // 用于得到指定同名字段的参数数�?,重写request.getParameterValues(String
													// s)
		ArrayList al = new ArrayList();
		if (parameter.isEmpty()) {
			return null;
		}
		Enumeration e = parameter.keys();
		while (e.hasMoreElements()) {
			String key = (String) e.nextElement();
			if (-1 != key.indexOf(s + "||||||||||") || key.equals(s)) {
				al.add(parameter.get(key));
			}
		}
		if (al.size() == 0) {
			return null;
		}
		String[] value = new String[al.size()];
		for (int i = 0; i < value.length; i++) {
			value[i] = (String) al.get(i);
		}
		return value;
	}

	public String getQueryString() {
		return queryString;
	}

	public int getCount() {
		return count;
	}

	public String[] getFileName() {
		return fileName;
	}

	public void setMaxFileSize(long size) {
		maxFileSize = size;
	}

	public void setTagFileName(String filename) {
		tagFileName = filename;
	}

	public void setSaveDir(String saveDir) { // 设置上载文件要保存的路径
		this.saveDir = saveDir;
		File testdir = new File(saveDir); // 为了保证目录存在,如果没有则新建该目录
		if (!testdir.exists()) {
			testdir.mkdirs();
		}
	}

	public void setCharset(String charset) { // 设置字符�?
		this.charset = charset;
	}

	public boolean uploadFile() throws ServletException, IOException { // 用户调用的上载方�?
		setCharset(request.getCharacterEncoding());
		return uploadFile(request.getInputStream());
	}

	public boolean uploadFile(ServletInputStream servletinputstream) throws // 取得央存数据的主方法
			ServletException, IOException {
		String line = null;
		byte[] buffer = new byte[256];
		while ((line = readLine(buffer, servletinputstream, charset)) != null) {
			if (line.startsWith("Content-Disposition: form-data;")) {
				int i = line.indexOf("filename=");
				if (i >= 0) { // 如果�?段分界符内的描述中有filename=,说明是文件的编码内容
					String fName = getFileName(line);
					if (fName.equals("")) {
						continue;
					}
					if (count == 0 && tagFileName.length() != 0) {
						String ext = fName
								.substring((fName.lastIndexOf(".") + 1));
						fName = tagFileName + "." + ext;
					}
					tmpFileName.add(fName);
					count++;
					while ((line = readLine(buffer, servletinputstream, charset)) != null) {
						if (line.length() <= 2) {
							break;
						}
					}
					File f = new File(saveDir, fName);
					FileOutputStream dos = new FileOutputStream(f);
					long size = 0l;
					while ((line = readLine(buffer, servletinputstream, null)) != null) {
						if (line.indexOf(boundary) != -1) {
							break;
						}
						size += len;
						if (size > maxFileSize) {
							throw new IOException("文件超过" + maxFileSize + "字节!");
						}
						dos.write(buffer, 0, len);
					}
					dos.close();
				} else { // 否则是字段编码的内容
					String key = getKey(line);
					String value = "";
					while ((line = readLine(buffer, servletinputstream, charset)) != null) {
						if (line.length() <= 2) {
							break;
						}
					}
					while ((line = readLine(buffer, servletinputstream, charset)) != null) {

						if (line.indexOf(boundary) != -1) {
							break;
						}
						value += line;
					}
					put(key, value.trim(), parameter);
				}
			}
		}
		if (queryString != null) {
			String[] each = split(queryString, "&");
			for (int k = 0; k < each.length; k++) {
				String[] nv = split(each[k], "=");
				if (nv.length == 2) {
					put(nv[0], nv[1], parameter);
				}
			}
		}
		fileName = new String[tmpFileName.size()];
		for (int k = 0; k < fileName.length; k++) {
			fileName[k] = (String) tmpFileName.get(k); // 把ArrayList中临时文件名倒入数据中供用户调用
		}
		if (fileName.length == 0) {
			return false; // 如果fileName数据为空说明没有上载任何文件
		}
		return true;
	}

	private void put(String key, String value, Hashtable ht) {
		if (!ht.containsKey(key)) {
			ht.put(key, value);
		} else { // 如果已经有了同名的KEY,就要把当前的key更名,同时要注意不能构成和KEY同名
			try {
				Thread.sleep(1); // 为了不在同一ms中产生两个相同的key
			} catch (Exception e) {
			}
			key += "||||||||||" + System.currentTimeMillis();
			ht.put(key, value);
		}
	}

	/*
	 * 调用ServletInputstream.readLine(byte[] b,int
	 * offset,length)方法,该方法是从ServletInputstream流中读一�?
	 * 到指定的byte数组,为了保证能够容纳�?�?,该byte[]b不应该小�?256,重写的readLine�?,调用了一个成员变量len�?
	 * 实际读到的字节数(有的行不�?256),则在文件内容写入时应该从byte数组中写入这个len长度的字节�?�不是整个byte[]
	 * 的长�?,但重写的这个方法返回的是String以便分析实际内容,不能返回len,�?以把len设为成员变量,在每次读操作�? 把实际长度赋给它.
	 * 也就是说在处理到文件的内容时数据既要以String形式返回以便分析�?始和结束标记,又要同时以byte[]的形式写到文�? 输出流中.
	 */
	public String readLine(byte[] Linebyte,
			ServletInputStream servletinputstream, String charset) {
		try {
			len = servletinputstream.readLine(Linebyte, 0, Linebyte.length);
			if (len == -1) {
				return null;
			}
			if (charset == null) {
				return new String(Linebyte, 0, len);
			} else {
				return new String(Linebyte, 0, len, charset);
			}

		} catch (Exception _ex) {
			return null;
		}

	}

	private String getFileName(String line) { // 从描述字符串中分离出文件�?
		if (line == null) {
			return "";
		}
		int i = line.indexOf("filename=");
		line = line.substring(i + 9).trim();
		i = line.lastIndexOf("\\");
		if (i < 0 || i >= line.length() - 1) {
			i = line.lastIndexOf("/");
			if (line.equals("\"\"")) {
				return "";
			}
			if (i < 0 || i >= line.length() - 1) {
				return line;
			}
		}
		return line.substring(i + 1, line.length() - 1);
	}

	private String getKey(String line) { // 从描述字符串中分离出字段�?
		if (line == null) {
			return "";
		}
		int i = line.indexOf("name=");
		line = line.substring(i + 5).trim();
		return line.substring(1, line.length() - 1);
	}

	public static String[] split(String strOb, String mark) {
		if (strOb == null) {
			return null;
		}
		StringTokenizer st = new StringTokenizer(strOb, mark);
		ArrayList tmp = new ArrayList();
		while (st.hasMoreTokens()) {
			tmp.add(st.nextToken());
		}
		String[] strArr = new String[tmp.size()];
		for (int i = 0; i < tmp.size(); i++) {
			strArr[i] = (String) tmp.get(i);
		}
		return strArr;
	}

	public static void downLoad(String filePath, HttpServletResponse response,
			boolean isOnLine) throws Exception {
		File f = new File(filePath);
		if (!f.exists()) {
			response.sendError(404, "File not found!");
			return;
		}
		BufferedInputStream br = new BufferedInputStream(new FileInputStream(f));
		byte[] buf = new byte[1024];
		int len = 0;

		response.reset(); // 非常重要
		if (isOnLine) { // 在线打开方式
			URL u = new URL("file:///" + filePath);
			response.setContentType(u.openConnection().getContentType());
			response.setHeader("Content-Disposition", "inline; filename="
					+ f.getName());
			// 文件名应该编码成UTF-8
		} else { // 纯下载方�?
			response.setContentType("application/x-msdownload");
			response.setHeader("Content-Disposition", "attachment; filename="
					+ f.getName());
		}
		OutputStream out = response.getOutputStream();
		while ((len = br.read(buf)) > 0)
			out.write(buf, 0, len);
		br.close();
		out.close();
	}
}