某产品为了防止跨目录使用了如下的代码处理路径: public static String getFileName(String filePath) { String fileName = ""; String separator = "/"; if(filePath.lastIndexOf("\\")>0){ separator = "\\"; } else{ separator = "/"; } fileName = filePath.substring(filePath.lastIndexOf(separator)+1); return fileName; } 以下哪种方法可以绕过该判断从而达到跨目录的结果? ../../../fileName ..\..\..\fileName ../../..\..\fileName ..\..\../../fileName
时间: 2024-04-07 13:32:07 浏览: 17
该方法使用了一个判断,如果路径中包含"\"则将路径分隔符设为"\",否则使用"/"作为分隔符。因此,可以绕过该判断的方法是使用一个既包含"\"又包含"/"的路径,例如使用"../../"来切换目录,但是不能通过任意输入字符串来实现跨目录,要根据实际情况来进行构造。因此,以下任何一种方法都不一定可以绕过该判断,需要具体情况具体分析。
相关问题
java使用nio实现web导入大文件代码
下面是使用Java NIO实现Web导入大文件的代码示例:
1. 创建上传文件处理的Servlet:
```java
@WebServlet("/upload")
@MultipartConfig
public class UploadServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String savePath = "/path/to/save/uploaded/files/";
File fileSaveDir = new File(savePath);
if (!fileSaveDir.exists()) {
fileSaveDir.mkdirs();
}
try {
for (Part part : request.getParts()) {
String fileName = getFileName(part);
if (fileName != null && !fileName.isEmpty()) {
String filePath = savePath + File.separator + fileName;
part.write(filePath);
}
}
request.setAttribute("message", "Upload has been done successfully!");
} catch (Exception ex) {
request.setAttribute("message", "There was an error: " + ex.getMessage());
}
request.getRequestDispatcher("/result.jsp").forward(request, response);
}
private String getFileName(final Part part) {
final String partHeader = part.getHeader("content-disposition");
for (String content : partHeader.split(";")) {
if (content.trim().startsWith("filename")) {
return content.substring(content.indexOf('=') + 1).trim().replace("\"", "");
}
}
return null;
}
}
```
2. 创建上传文件处理的JSP页面:
```jsp
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8" %>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>File Upload Example</title>
</head>
<body>
<h1>File Upload Example</h1>
<form action="upload" method="post" enctype="multipart/form-data">
<label for="file">Choose file to upload:</label>
<input type="file" id="file" name="file"><br><br>
<input type="submit" value="Upload"/>
</form>
<% if (request.getAttribute("message") != null) { %>
<p><%= request.getAttribute("message") %></p>
<% } %>
</body>
</html>
```
3. 在web.xml文件中配置Servlet:
```xml
<web-app>
<servlet>
<servlet-name>UploadServlet</servlet-name>
<servlet-class>com.example.UploadServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>UploadServlet</servlet-name>
<url-pattern>/upload</url-pattern>
</servlet-mapping>
</web-app>
```
4. 运行项目并访问上传文件的JSP页面,选择要上传的文件并点击“上传”按钮,上传的文件将被保存到指定的路径中。
这个示例使用Java NIO的MultipartConfig注解来实现文件上传,它允许您在Servlet中处理多部分数据。在上传文件时,Servlet遍历所有部分,并将每个部分写入磁盘上的文件。在此示例中,我们使用了Java IO API来实现文件写入操作。
用java代码写一个多线程下载文件接口
好的,以下是一个简单的多线程下载文件接口的 Java 代码:
```java
import java.io.*;
import java.net.URL;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
public class MultiThreadedDownloader {
private static final int BUFFER_SIZE = 4096;
private static final int NUM_THREADS = 4;
public static void download(String fileUrl, String saveDir) throws IOException {
URL url = new URL(fileUrl);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
int responseCode = conn.getResponseCode();
if (responseCode != HttpURLConnection.HTTP_OK) {
throw new IOException("Server returned HTTP response code: " + responseCode);
}
String fileName = getFileName(conn);
String filePath = saveDir + File.separator + fileName;
ExecutorService executor = Executors.newFixedThreadPool(NUM_THREADS);
int fileSize = conn.getContentLength();
int numParts = fileSize / BUFFER_SIZE + 1;
for (int i = 0; i < numParts; i++) {
int start = i * BUFFER_SIZE;
int end = Math.min((i + 1) * BUFFER_SIZE, fileSize);
executor.execute(new DownloadTask(url, filePath, start, end));
}
executor.shutdown();
while (!executor.isTerminated()) {
}
System.out.println("File downloaded to: " + filePath);
}
private static String getFileName(HttpURLConnection conn) {
String fileName = "";
String disposition = conn.getHeaderField("Content-Disposition");
String contentType = conn.getContentType();
int contentLength = conn.getContentLength();
if (disposition != null) {
int index = disposition.indexOf("filename=");
if (index > 0) {
fileName = disposition.substring(index + 10, disposition.length() - 1);
}
} else {
fileName = conn.getURL().getFile();
fileName = fileName.substring(fileName.lastIndexOf("/") + 1);
}
return fileName;
}
private static class DownloadTask implements Runnable {
private URL url;
private String filePath;
private int start;
private int end;
public DownloadTask(URL url, String filePath, int start, int end) {
this.url = url;
this.filePath = filePath;
this.start = start;
this.end = end;
}
@Override
public void run() {
try {
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setRequestMethod("GET");
conn.setRequestProperty("Range", "bytes=" + start + "-" + end);
InputStream inputStream = conn.getInputStream();
RandomAccessFile file = new RandomAccessFile(filePath, "rw");
file.seek(start);
byte[] buffer = new byte[BUFFER_SIZE];
int bytesRead;
while ((bytesRead = inputStream.read(buffer)) != -1) {
file.write(buffer, 0, bytesRead);
}
file.close();
inputStream.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
```
你可以调用 `MultiThreadedDownloader.download(fileUrl, saveDir)` 方法来下载文件,其中 `fileUrl` 是文件的 URL,`saveDir` 是保存文件的目录。这个方法会启动多个线程来下载文件,提高下载速度。