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java 如何推送附件

2026-03-18 07:20:29Java

使用 JavaMail API 发送带附件的邮件

引入 JavaMail 依赖（Maven 项目）：

<dependency>
    <groupId>com.sun.mail</groupId>
    <artifactId>javax.mail</artifactId>
    <version>1.6.2</version>
</dependency>

创建邮件并添加附件：

java 如何推送附件

Properties props = new Properties();
props.put("mail.smtp.host", "smtp.example.com");
props.put("mail.smtp.port", "587");
props.put("mail.smtp.auth", "true");
props.put("mail.smtp.starttls.enable", "true");

Session session = Session.getInstance(props, new Authenticator() {
    protected PasswordAuthentication getPasswordAuthentication() {
        return new PasswordAuthentication("username", "password");
    }
});

try {
    Message message = new MimeMessage(session);
    message.setFrom(new InternetAddress("from@example.com"));
    message.setRecipients(Message.RecipientType.TO, InternetAddress.parse("to@example.com"));
    message.setSubject("Email with Attachment");

    Multipart multipart = new MimeMultipart();

    // 邮件正文
    MimeBodyPart messageBodyPart = new MimeBodyPart();
    messageBodyPart.setText("This email contains an attachment");
    multipart.addBodyPart(messageBodyPart);

    // 添加附件
    MimeBodyPart attachmentPart = new MimeBodyPart();
    attachmentPart.attachFile(new File("path/to/attachment.pdf"));
    multipart.addBodyPart(attachmentPart);

    message.setContent(multipart);
    Transport.send(message);
} catch (Exception e) {
    e.printStackTrace();
}

使用 HTTP 客户端发送带附件的请求

使用 Apache HttpClient 发送 multipart/form-data 请求：

java 如何推送附件

CloseableHttpClient httpClient = HttpClients.createDefault();
HttpPost uploadFile = new HttpPost("http://example.com/upload");

MultipartEntityBuilder builder = MultipartEntityBuilder.create();
builder.addTextBody("field1", "value1", TEXT_PLAIN);
builder.addBinaryBody("file", new File("path/to/file"), ContentType.APPLICATION_OCTET_STREAM, "filename.ext");

HttpEntity multipart = builder.build();
uploadFile.setEntity(multipart);

CloseableHttpResponse response = httpClient.execute(uploadFile);
HttpEntity responseEntity = response.getEntity();

使用 Spring Boot 上传文件

创建文件上传控制器：

@RestController
public class FileUploadController {
    @PostMapping("/upload")
    public ResponseEntity<String> handleFileUpload(@RequestParam("file") MultipartFile file) {
        try {
            byte[] bytes = file.getBytes();
            Path path = Paths.get("uploads/" + file.getOriginalFilename());
            Files.write(path, bytes);
            return ResponseEntity.ok("File uploaded successfully");
        } catch (IOException e) {
            return ResponseEntity.status(500).body("Upload failed");
        }
    }
}

使用 FTP 协议上传文件

使用 Apache Commons Net 进行 FTP 文件传输：

FTPClient ftpClient = new FTPClient();
try {
    ftpClient.connect("ftp.example.com");
    ftpClient.login("username", "password");
    ftpClient.enterLocalPassiveMode();

    File localFile = new File("local/path/file.txt");
    InputStream inputStream = new FileInputStream(localFile);
    boolean success = ftpClient.storeFile("remote/path/file.txt", inputStream);
    inputStream.close();

    if (success) {
        System.out.println("File uploaded successfully");
    }
} finally {
    if (ftpClient.isConnected()) {
        ftpClient.logout();
        ftpClient.disconnect();
    }
}