这是一些代码，可能会帮助您，它来自我的一个旧项目，其中删除了许多无关的内容，以物有所值。基本上，我认为您问题中的代码缺少HTTP协议要求的某些部分
public class UploaderExample{ private static final String Boundary = "--7d021a37605f0"; public void upload(URL url, List<File> files) throws Exception { HttpURLConnection theUrlConnection = (HttpURLConnection) url.openConnection(); theUrlConnection.setDoOutput(true); theUrlConnection.setDoInput(true); theUrlConnection.setUseCaches(false); theUrlConnection.setChunkedStreamingMode(1024); theUrlConnection.setRequestProperty("Content-Type", "multipart/form-data; boundary=" + Boundary); DataOutputStream httpOut = new DataOutputStream(theUrlConnection.getOutputStream()); for (int i = 0; i < files.size(); i++) { File f = files.get(i); String str = "--" + Boundary + "rn" + "Content-Disposition: form-data;name="file" + i + ""; filename="" + f.getName() + ""rn" + "Content-Type: image/pngrn" + "rn"; httpOut.write(str.getBytes()); FileInputStream uploadFileReader = new FileInputStream(f); int numBytesToRead = 1024; int availableBytesToRead; while ((availableBytesToRead = uploadFileReader.available()) > 0) { byte[] bufferBytesRead; bufferBytesRead = availableBytesToRead >= numBytesToRead ? new byte[numBytesToRead] : new byte[availableBytesToRead]; uploadFileReader.read(bufferBytesRead); httpOut.write(bufferBytesRead); httpOut.flush(); } httpOut.write(("--" + Boundary + "--rn").getBytes()); } httpOut.write(("--" + Boundary + "--rn").getBytes()); httpOut.flush(); httpOut.close(); // read & parse the response InputStream is = theUrlConnection.getInputStream(); StringBuilder response = new StringBuilder(); byte[] respBuffer = new byte[4096]; while (is.read(respBuffer) >= 0) { response.append(new String(respBuffer).trim()); } is.close(); System.out.println(response.toString()); } public static void main(String[] args) throws Exception { List<File> list = new ArrayList<File>(); list.add(new File("C:\square.png")); list.add(new File("C:\narrow.png")); UploaderExample uploader = new UploaderExample(); uploader.upload(new URL("http://systemout.com/upload.php"), list); }}
