java上传图片stringBuffer

您可以使用以下代码将图片转换为字符串并上传：

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

public class ImageUploader {
    public static void main(String[] args) throws Exception {
        String imageUrl = "http://example.com/image.jpg"; // 图片的URL地址
        String boundary = "---------------------------" + System.currentTimeMillis(); // 分隔符
        URL url = new URL("http://example.com/upload"); // 上传接口的URL地址
        HttpURLConnection conn = (HttpURLConnection) url.openConnection();
        conn.setRequestMethod("POST");
        conn.setDoOutput(true);
        conn.setRequestProperty("Content-Type", "multipart/form-data; boundary=" + boundary);

        OutputStream out = conn.getOutputStream();
        PrintWriter writer = new PrintWriter(new OutputStreamWriter(out, "UTF-8"), true);

        // 添加图片数据
        writer.append("--").append(boundary).append("\r\n");
        writer.append("Content-Disposition: form-data; name=\"file\"; filename=\"image.jpg\"\r\n");
        writer.append("Content-Type: image/jpeg\r\n\r\n");
        writer.flush();

        InputStream in = new URL(imageUrl).openStream();
        byte[] buffer = new byte[4096];
        int length;
        while ((length = in.read(buffer)) > 0) {
            out.write(buffer, 0, length);
        }
        out.flush();
        in.close();

        writer.append("\r\n").flush();

        // 添加其他参数
        writer.append("--").append(boundary).append("\r\n");
        writer.append("Content-Disposition: form-data; name=\"param1\"\r\n\r\n");
        writer.append("value1").append("\r\n");
        writer.flush();

        writer.append("--").append(boundary).append("--\r\n");
        writer.close();

        BufferedReader reader = new BufferedReader(new InputStreamReader(conn.getInputStream()));
        StringBuffer stringBuffer = new StringBuffer();
        String line;
        while ((line = reader.readLine()) != null) {
            stringBuffer.append(line);
        }
        reader.close();

        System.out.println(stringBuffer.toString());
    }
}