java使用nio实现web导入大文件代码
时间: 2023-11-22 12:53:22 浏览: 82
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。
阅读全文