FLASK与JAVA的文件互传（单文件互传亲测）

配置：JAVA需要的jar包httpclient4-5-14

python需要的配置：

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# # 安装 Windows 兼容版本
# pip install python-magic-bin
#pip install flask

JAVA端的代码：

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HttpClient4514FileUpload.java

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package HttpFlask;
import org.apache.http.HttpEntity;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.ContentType;
import org.apache.http.entity.mime.MultipartEntityBuilder;
import org.apache.http.entity.mime.content.FileBody;
import org.apache.http.entity.mime.content.StringBody;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;

import java.io.File;
import java.io.IOException;
import java.nio.charset.StandardCharsets;

public class HttpClient4514FileUpload {
    /**
     * 基础文件上传方法
     * @param url 上传地址
     * @param file 要上传的文件
     * @return 服务器响应内容
     */
    public static String uploadFile(String url, File file) throws IOException {
        CloseableHttpClient httpClient = HttpClients.createDefault();

        try {
            HttpPost httpPost = new HttpPost(url);

            // 使用 MultipartEntityBuilder 构建多部分表单数据
            MultipartEntityBuilder builder = MultipartEntityBuilder.create();

            // 添加文件部分
            FileBody fileBody = new FileBody(file, ContentType.DEFAULT_BINARY, file.getName());
            builder.addPart("file", fileBody); // "file" 是表单字段名

            // 添加文本参数（可选）
            StringBody commentBody = new StringBody("文件上传示例",
                    ContentType.TEXT_PLAIN.withCharset(StandardCharsets.UTF_8));
            builder.addPart("comment", commentBody);

            // 构建实体
            HttpEntity multipartEntity = builder.build();
            httpPost.setEntity(multipartEntity);

            // 执行请求
            CloseableHttpResponse response = httpClient.execute(httpPost);

            try {
                // 获取响应实体
                HttpEntity responseEntity = response.getEntity();
                String responseString = EntityUtils.toString(responseEntity);

                // 确保响应实体被完全消费
                EntityUtils.consume(responseEntity);

                System.out.println("响应状态: " + response.getStatusLine().getStatusCode());
                return responseString;

            } finally {
                response.close();
            }

        } finally {
            httpClient.close();
        }
    }
}

JAVA测试：HTTPFlask

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public class FileHttpFlask {

    public static void main(String[] args) {

        try {
            // 示例1: 基础文件上传
            String urlSingle = "http://127.0.0.1:5000/api/upload";
            File file = new File("E:\\testWorkPlace\\testrun\\src\\HttpFlask\\upload.txt");
            String result = HttpClient4514FileUpload.uploadFile(urlSingle, file);
            System.out.println("基础上传结果: " + result);


        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

对应flask代码：

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from flask import Flask, request, jsonify, render_template_string, send_file
import os
import uuid
from werkzeug.utils import secure_filename
from datetime import datetime
import magic  # 用于更准确的文件类型检测
from datetime import datetime
import time
# # 安装 Windows 兼容版本
# pip install python-magic-bin
app = Flask(__name__)

# 配置文件上传
app.config.update(
    UPLOAD_FOLDER='uploads',
    MAX_CONTENT_LENGTH=16 * 1024 * 1024,  # 16MB
    ALLOWED_EXTENSIONS={'txt', 'pdf', 'png', 'jpg', 'jpeg', 'gif', 'doc', 'docx', 'zip'},
    SECRET_KEY='your-secret-key-here'
)

# 用于存储上传统计信息
upload_stats = {
    'total_files': 0,
    'total_size': 0,
    'last_upload': None
}
# 创建上传目录
os.makedirs(app.config['UPLOAD_FOLDER'], exist_ok=True)


class FileUploader:
    """文件上传工具类"""

    @staticmethod
    def allowed_file(filename):
        """检查文件扩展名"""
        return '.' in filename and \
               filename.rsplit('.', 1)[1].lower() in app.config['ALLOWED_EXTENSIONS']

    @staticmethod
    def generate_unique_filename(original_filename):
        """生成唯一文件名"""
        timestamp = datetime.now().strftime("%Y%m%d_%H%M%S_%f")
        unique_id = str(uuid.uuid4())[:8]
        safe_name = secure_filename(original_filename)
        return f"{timestamp}_{unique_id}_{safe_name}"

    @staticmethod
    def get_file_info(file_path):
        """获取文件详细信息"""
        stat = os.stat(file_path)
        file_type = "unknown"

        try:
            # 使用python-magic检测文件类型
            import magic
            file_type = magic.from_file(file_path, mime=True)
        except:
            # 备用方案：使用文件扩展名
            ext = os.path.splitext(file_path)[1].lower()
            file_type = f"application/{ext[1:]}" if ext else "unknown"

        return {
            'size': stat.st_size,
            'created_time': datetime.fromtimestamp(stat.st_ctime).isoformat(),
            'modified_time': datetime.fromtimestamp(stat.st_mtime).isoformat(),
            'type': file_type
        }




@app.route('/api/upload', methods=['POST'])
def api_upload_file():
    """API: 单文件上传"""
    try:
        if 'file' not in request.files:
            return jsonify({'success': False, 'error': '没有文件部分'}), 400

        file = request.files['file']
        description = request.form.get('description', '')
        tags = request.form.get('tags', '')

        if file.filename == '':
            return jsonify({'success': False, 'error': '没有选择文件'}), 400

        if not FileUploader.allowed_file(file.filename):
            return jsonify({'success': False, 'error': '不允许的文件类型'}), 400

        # 生成唯一文件名
        unique_filename = FileUploader.generate_unique_filename(file.filename)
        file_path = os.path.join(app.config['UPLOAD_FOLDER'], unique_filename)

        # 保存文件
        file.save(file_path)

        # 获取文件信息
        file_info = FileUploader.get_file_info(file_path)

        response_data = {
            'success': True,
            'message': '文件上传成功',
            'file': {
                'id': unique_filename,
                'original_name': file.filename,
                'saved_name': unique_filename,
                'description': description,
                'tags': [tag.strip() for tag in tags.split(',')] if tags else [],
                'upload_time': datetime.now().isoformat(),
                **file_info
            }
        }

        return jsonify(response_data), 200

    except Exception as e:
        return jsonify({'success': False, 'error': str(e)}), 500

运行结果：

上传成功！