java实现文件接收_Java实现文件上传
1. 创建一个Servlet类，处理文件上传请求。
```java
import java.io.File;
import java.io.IOException;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.annotation.MultipartConfig;
import javax.servlet.annotation.WebServlet;
public class FileUploadServlet extends HttpServlet
private static final long serialVersionUID = 1L;
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException
// 检查请求是否为multipart/form-data类型
if (!ServletFileUpload.isMultipartContent(request))
Writer(.println("Error: Form must has enctype=multipart/form-data.");
response.setStatus(HttpServletResponse.SC_BAD_REQUEST);
return;
}
// 创建一个DiskFileItemFactory对象，用于设置临时存储文件的目录和大小限制
java创建文件DiskFileItemFactory factory = new DiskFileItemFactory(;
factory.setSizeThreshold(1024 * 1024); // 设置内存缓冲区大小为1MB
factory.setRepository(new Property("pdir"))); // 设置临时文件目录
// 创建ServletFileUpload对象，并设置上传文件的最大大小限制
ServletFileUpload upload = new ServletFileUpload(factory);
upload.setSizeMax(1024 * 1024 * 10); // 设置上传文件的最大大小为10MB
try
List<FileItem> items = upload.parseRequest(request); // 解析请求中的所有文件项
for (FileItem item : items)
if (!item.isFormField() { // 判断当前文件项是否为普通表单字段
String fileName = new Name().getName(; // 获取文件名
String filePath = "C:/upload/" + fileName; // 设置文件保存路径
item.write(new File(filePath)); // 保存文件到服务器
Writer(.println("File uploaded successfully: " + fileName);
}
}
} catch (FileUploadException e)
Writer(.println("Error: " + e.getMessage();
response.setStatus(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
} catch (Exception e)
Writer(.println("Error: " + e.getMessage();
response.setStatus(HttpServletResponse.SC_BAD_REQUEST);
}
}
```
2. 在l中注册Servlet。
```xml
<web-app>
<display-name>File Upload Example</display-name>
<servlet>
<servlet-name>FileUploadServlet</servlet-name>
</servlet>
<servlet-mapping>
<servlet-name>FileUploadServlet</servlet-name>
<url-pattern>/upload</url-pattern>
</servlet-mapping>
</web-app>
```
3. 创建一个html文件，包含一个文件上传表单。
```html
<!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">
<input type="file" name="file" required>
<input type="submit" value="Upload">
</form>
</body>
</html>
```

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