java通过链接下载文件
时间: 2023-11-18 22:42:12 浏览: 44
你可以使用Java的URLConnection类来下载文件。以下是一个简单的示例代码:
```java
import java.io.*;
import java.net.*;
public class FileDownloader {
public static void main(String[] args) {
String fileUrl = "http://example.com/file.pdf";
String saveDir = "/home/user/Documents/";
try {
URL url = new URL(fileUrl);
HttpURLConnection httpConn = (HttpURLConnection) url.openConnection();
int responseCode = httpConn.getResponseCode();
if (responseCode == HttpURLConnection.HTTP_OK) {
String fileName = "";
String disposition = httpConn.getHeaderField("Content-Disposition");
if (disposition != null) {
int index = disposition.indexOf("filename=");
if (index > 0) {
fileName = disposition.substring(index + 10, disposition.length() - 1);
}
} else {
fileName = fileUrl.substring(fileUrl.lastIndexOf("/") + 1, fileUrl.length());
}
InputStream inputStream = httpConn.getInputStream();
String saveFilePath = saveDir + File.separator + fileName;
FileOutputStream outputStream = new FileOutputStream(saveFilePath);
int bytesRead = -1;
byte[] buffer = new byte[4096];
while ((bytesRead = inputStream.read(buffer)) != -1) {
outputStream.write(buffer, 0, bytesRead);
}
outputStream.close();
inputStream.close();
System.out.println("File downloaded");
} else {
System.out.println("No file to download. Server replied HTTP code: " + responseCode);
}
httpConn.disconnect();
} catch (IOException e) {
System.out.println("Error downloading file: " + e.getMessage());
e.printStackTrace();
}
}
}
```
在上面的代码中,你需要将`fileUrl`变量设置为要下载的文件的URL,将`saveDir`变量设置为要将文件保存的本地目录。代码将自动从`fileUrl`下载文件并将其保存在`saveDir`目录中。
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