SmartUpload 中文文件名下载的时候乱码

首先工程要引用com.jspsmart.upload jar包然后新建一下java类

package com.common;

import java.io.*;

import javax.servlet.*;
import javax.servlet.http.*;
import javax.servlet.jsp.JspWriter;
import javax.servlet.jsp.PageContext;

import com.jspsmart.upload.SmartUploadException;

public class SmartDownload {
?protected byte m_binArray[];
?protected HttpServletRequest m_request;
?protected HttpServletResponse m_response;
?protected ServletContext m_application;
?private boolean m_denyPhysicalPath;

?private String m_contentDisposition;
?

?public SmartDownload() {
??m_denyPhysicalPath = false;
??m_contentDisposition = new String();

?}

?public void setContentDisposition(String contentDisposition) {
??m_contentDisposition = contentDisposition;
?}

?public final void initialize(ServletConfig config,
???HttpServletRequest request, HttpServletResponse response)
???throws ServletException {
??m_application = config.getServletContext();
??m_request = request;
??m_response = response;
?}

?public final void initialize(PageContext pageContext)
???throws ServletException {
??m_application = pageContext.getServletContext();
??m_request = (HttpServletRequest) pageContext.getRequest();
??m_response = (HttpServletResponse) pageContext.getResponse();
?}

?/**
? * @deprecated Method initialize is deprecated
? */

?public final void initialize(ServletContext application,
???HttpSession session, HttpServletRequest request,
???HttpServletResponse response, JspWriter out)
???throws ServletException {
??m_application = application;
??m_request = request;
??m_response = response;
?}

?public void downloadFile(String sourceFilePathName, String contentType,
???String destFileName, String charsetName)
???throws SmartUploadException, IOException, ServletException {
??downloadFile(sourceFilePathName, contentType, destFileName, 65000,
????charsetName);
?}

?public void downloadFile(String sourceFilePathName, String contentType,
???String destFileName, int blockSize, String charsetName)
???throws SmartUploadException, IOException, ServletException {
??if (sourceFilePathName == null)
???throw new IllegalArgumentException(String
?????.valueOf((new StringBuffer("File '")).append(
???????sourceFilePathName).append("' not found (1040).")));
??if (sourceFilePathName.equals(""))
???throw new IllegalArgumentException(String
?????.valueOf((new StringBuffer("File '")).append(
???????sourceFilePathName).append("' not found (1040).")));
??if (!isVirtual(sourceFilePathName) && m_denyPhysicalPath)
???throw new SecurityException("Physical path is denied (1035).");
??if (isVirtual(sourceFilePathName))
???sourceFilePathName = m_application.getRealPath(sourceFilePathName);
??File file = new File(sourceFilePathName);
??FileInputStream fileIn = new FileInputStream(file);
??long fileLen = file.length();
??int readBytes = 0;
??int totalRead = 0;
??byte b[] = new byte[blockSize];
??if (contentType == null)
???m_response.setContentType("application/x-msdownload");
??else if (contentType.length() == 0)
???m_response.setContentType("application/x-msdownload");
??else
???m_response.setContentType(contentType);
??m_response.setContentLength((int) fileLen);
??m_contentDisposition = m_contentDisposition == null ? "attachment;"
????: m_contentDisposition;
??if (destFileName == null)
???m_response.setHeader("Content-Disposition", m_contentDisposition
?????+ " filename="
?????+ toUtf8String(getFileName(sourceFilePathName)));

??//???m_response.setHeader("Content-Disposition", String
??//?????.valueOf((new StringBuffer(String
??//???????.valueOf(m_contentDisposition))).append(
??//???????" filename=").append(
??//???????URLEncoder.encode(getFileName(sourceFilePathName),
??//?????????charsetName))));
??else if (destFileName.length() == 0)
???m_response.setHeader("Content-Disposition", m_contentDisposition);
??else
???m_response.setHeader("Content-Disposition", m_contentDisposition
?????+ " filename=" + toUtf8String(destFileName));
??//
??//???m_response.setHeader("Content-Disposition", String
??//?????.valueOf((new StringBuffer(String
??//???????.valueOf(m_contentDisposition))).append(
??//???????" filename=").append(destFileName)));
??while ((long) totalRead < fileLen) {
???readBytes = fileIn.read(b, 0, blockSize);
???totalRead += readBytes;
???m_response.getOutputStream().write(b, 0, readBytes);
??}
??fileIn.close();
?}

?public static String toUtf8String(String s) {
??StringBuffer sb = new StringBuffer();
??for (int i = 0; i < s.length(); i++) {
???char c = s.charAt(i);
???if (c >= 0 && c <= 255) {
????sb.append(c);
???} else {
????byte[] b;
????try {
?????b = Character.toString(c).getBytes("utf-8");
????} catch (Exception ex) {
?????System.out.println(ex);
?????b = new byte[0];
????}
????for (int j = 0; j < b.length; j++) {
?????int k = b[j];
?????if (k < 0)
??????k += 256;
?????sb.append("%" + Integer.toHexString(k).toUpperCase());
????}
???}
??}
??return sb.toString();
?}

?private String getFileName(String filePathName)
???throws UnsupportedEncodingException {
??int pos = 0;
??filePathName = filePathName.replace('\\', '/');
??if ((pos = filePathName.lastIndexOf('/')) != -1)
???return filePathName.substring(pos + 1);
??else
???return filePathName;
?}

?private boolean isVirtual(String pathName) {
??if (m_application.getRealPath(pathName) != null) {
???File virtualFile = new File(m_application.getRealPath(pathName));
???return virtualFile.exists();
??} else {
???return false;
??}
?}

}