java发送http formdata请求

使用Java发送HTTP FormData请求可以使用Java的HttpURLConnection类。以下是示例代码：

import java.io.*;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.UUID;

public class FormDataHttpRequest {

    private static final String LINE_FEED = "\r\n";
    private static final String BOUNDARY = UUID.randomUUID().toString();

    public static void main(String[] args) throws IOException {
        String url = "http://example.com/upload";
        String charset = "UTF-8";
        File textFile = new File("text.txt");
        File binaryFile = new File("image.png");

        HttpURLConnection connection = (HttpURLConnection) new URL(url).openConnection();
        connection.setDoOutput(true);
        connection.setRequestMethod("POST");
        connection.setRequestProperty("Content-Type", "multipart/form-data; boundary=" + BOUNDARY);

        try (OutputStream outputStream = connection.getOutputStream();
             PrintWriter writer = new PrintWriter(new OutputStreamWriter(outputStream, charset), true)) {
            // Add text field
            writer.append("--").append(BOUNDARY).append(LINE_FEED);
            writer.append("Content-Disposition: form-data; name=\"text\"").append(LINE_FEED);
            writer.append("Content-Type: text/plain; charset=").append(charset).append(LINE_FEED);
            writer.append(LINE_FEED);
            writer.append("Text field value").append(LINE_FEED);
            writer.flush();

            // Add binary file
            writer.append("--").append(BOUNDARY).append(LINE_FEED);
            writer.append("Content-Disposition: form-data; name=\"binaryFile\"; filename=\"")
                    .append(binaryFile.getName()).append("\"").append(LINE_FEED);
            writer.append("Content-Type: ").append(connection.guessContentTypeFromName(binaryFile.getName()))
                    .append(LINE_FEED);
            writer.append("Content-Transfer-Encoding: binary").append(LINE_FEED);
            writer.append(LINE_FEED);
            writer.flush();
            Files.copy(binaryFile.toPath(), outputStream);
            outputStream.flush();

            // End boundary
            writer.append(LINE_FEED).append("--").append(BOUNDARY).append("--").append(LINE_FEED);
            writer.flush();
        }

        // Handle response
        int responseCode = connection.getResponseCode();
        if (responseCode >= 200 && responseCode < 300) {
            try (BufferedReader reader = new BufferedReader(new InputStreamReader(connection.getInputStream()))) {
                String line;
                while ((line = reader.readLine()) != null) {
                    System.out.println(line);
                }
            }
        } else {
            System.out.println("Request failed with response code " + responseCode);
        }
    }
}

此代码将发送一个HTTP POST请求，其中包含一个文本字段和一个二进制文件。您可以根据需要添加或删除表单字段。注意，此代码将使用Java 7的Files.copy（）方法复制二进制文件。如果您使用的是Java 6或更早版本，请使用其他方法复制文件。