Java http 調用接口提交表單以及文件

Java HttpURLConnection 使用

/**
 * 
 */
package com.demo.java;

import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLConnection;
import java.util.List;
import java.util.Map;

/**
 * <p>描述：</p>
 * 
 * @author  saohuo
 * @date    2019年11月4日
 * @version 
 */
public class MultipartFormDataPost {
	
	// multipart/form-data; 表單各字段提交分隔符
	private static String boundary = "--69695201314";
	
	public void submit(Map<String, String> generalField, List<File> files) throws Exception {
		HttpURLConnection connection = null;
		OutputStream os = null;
		URL url = new URL("http:");
		connection = (HttpURLConnection) url.openConnection();
		connection.setDoInput(true);
		connection.setDoOutput(true);
		connection.setRequestMethod("POST");
		connection.setUseCaches(false);
		connection.setRequestProperty("Connection", "Keep-Alive");
		connection.setRequestProperty("Accept-Charset", "UTF-8");
		connection.setRequestProperty("content-type", "multipart/form-data;boundary="+boundary);
		os = new DataOutputStream(connection.getOutputStream());
		// 文本參數組裝
		StringBuffer textFormBody = new StringBuffer();
		Map<String, String> formField = generalField;
		formField.forEach((k,v) -> {
			textFormBody.append("\r\n").append("--").append(boundary).append("\r\n");
			textFormBody.append("Content-Disposition: form-data; name=\""+k+"\"");
			textFormBody.append("\r\n\r\n");//名稱與數據之間要有兩個回車換行
			textFormBody.append(v);
		});
		// 提交文本表單
		os.write(textFormBody.toString().getBytes("UTF-8")); 
		// 文件數據
		if (files != null && !files.isEmpty()) {
			int fileIndex = 0;
			for(File file : files) {
				String filename = file.getName();
				String fileMinetype = URLConnection.getFileNameMap().getContentTypeFor(filename);
				StringBuffer fileFormBody = new StringBuffer();
				fileFormBody.append("\r\n").append("--").append(boundary).append("\r\n");
				fileFormBody.append("Content-Disposition: form-data; name=\"files["+fileIndex+"]\"; filename=\"" + filename + "\"");
				fileFormBody.append("\r\n");
				fileFormBody.append("Content-Type:" + fileMinetype);
				fileFormBody.append("\r\n\r\n");
				// 提交文件基本信息（文件名、文件長度、文件類型等）
				os.write(fileFormBody.toString().getBytes());
				InputStream fileStream = new FileInputStream(file);
				DataInputStream fileDataIs = new DataInputStream(fileStream);
				int filebytes = 0;
				byte[] filebufferOut = new byte[1024];
				while ((filebytes = fileDataIs.read(filebufferOut)) != -1) {
					os.write(filebufferOut, 0, filebytes);
				}
				fileDataIs.close();
				fileIndex++;
			}
		} // 文件寫入結束
		// 最後寫入結束標識
		byte[] endBodyData = ("\r\n--" + boundary + "--\r\n").getBytes();
		os.write(endBodyData);
		os.flush();
		int responseCode = connection.getResponseCode();
		// 提交結果狀態碼
		System.out.println(responseCode);
	}

}