用java写入参是url,参数,和上传文件的方法

在Java中，你可以使用`HttpURLConnection`或者更现代的`HttpClient`库来发送POST请求，其中包含URL、查询参数以及上传的文件。下面是一个简单的示例，展示如何使用`HttpURLConnection`：

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

public void uploadFileWithParameters(String urlString, String queryParams, File file) throws IOException {
    URL url = new URL(urlString);
    HttpURLConnection connection = (HttpURLConnection) url.openConnection();
    
    // 设置请求方法为POST
    connection.setRequestMethod("POST");
    
    // 添加查询参数到请求头
    StringBuilder query = new StringBuilder();
    query.append("param1=").append(queryParams); // 替换为实际的参数名和值
    if (!query.toString().isEmpty()) {
        connection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
        connection.setDoOutput(true);
        try (OutputStream os = connection.getOutputStream()) {
            byte[] paramsBytes = query.toString().getBytes("UTF-8");
            os.write(paramsBytes);
        }
    }

    // 如果有文件需要上传，设置文件流
    if (file != null) {
        connection.setRequestProperty("Content-Disposition", "form-data; name=\"file\"; filename=\"" + file.getName() + "\"");
        connection.setRequestProperty("Content-Type", "multipart/form-data");
        FileInputStream fis = new FileInputStream(file);
        try (InputStream is = fis) {
            byte[] bytes = new byte[4096];
            int length;
            while ((length = is.read(bytes)) > 0) {
                OutputStream outputStream = connection.getOutputStream();
                outputStream.write(bytes, 0, length);
            }
        } finally {
            fis.close();
        }
    }

    // 获取响应并关闭连接
    int responseCode = connection.getResponseCode();
    System.out.println("Response Code : " + responseCode);

    connection.disconnect();
}