获取webroot上的文件

public static void downloadFile(String filePath, javax.servlet.http.HttpServletResponse response) {
??String fileName = ""; //文件名，输出到用户的下载对话框
??//从文件完整路径中提取文件名，并进行编码转换，防止不能正确显示中文名
??try {
???if (filePath.lastIndexOf("/") > 0) {
????fileName = new String(filePath.substring(filePath.lastIndexOf("/") + 1, filePath.length()).getBytes(
??????"GB2312"), "ISO8859_1");
???} else if (filePath.lastIndexOf("\\") > 0) {
????fileName = new String(filePath.substring(filePath.lastIndexOf("\\") + 1, filePath.length()).getBytes(
??????"GB2312"), "ISO8859_1");
???}
??} catch (Exception e) {
??}
??//打开指定文件的流信息
??FileInputStream fs = null;
??try {
???fs = new FileInputStream(new File(filePath));
??} catch (FileNotFoundException e) {
???e.printStackTrace();
???return;
??}
??//设置响应头和保存文件名
??response.setContentType("APPLICATION/OCTET-STREAM");
??response.setHeader("Content-Disposition", "attachment; filename=\"" + fileName + "\"");
??//写出流信息
??int b = 0;
??try {
???PrintWriter out = response.getWriter();
???while ((b = fs.read()) != -1) {
????out.write(b);
???}
???fs.close();
???out.close();
???System.out.println("文件下载完毕.");
??} catch (Exception e) {
???e.printStackTrace();
???System.out.println("下载文件失败!");
??}
?}