java发送form-data形式请求不带文件参数

在Java中，如果你需要发送一个只包含表单数据（即非文件上传）的`FORM-DATA`类型的HTTP请求而不携带文件参数，你可以使用`HttpURLConnection`、`HttpClient`或者第三方库如`Apache HttpClient`或`OkHttp`。这里以`HttpURLConnection`为例，展示如何构建这样的请求：

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

public class FormDataRequest {
    private static final String URL_STRING = "http://example.com/api"; // 替换为你实际的URL

    public void sendData(String key, String value) throws Exception {
        URL url = new URL(URL_STRING);
        HttpURLConnection connection = (HttpURLConnection) url.openConnection();
        connection.setRequestMethod("POST");
        connection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");

        try (OutputStream os = connection.getOutputStream()) {
            byte[] data = ("key=" + key + "&value=" + value).getBytes("UTF-8"); // 构造表单数据字符串
            os.write(data);
        }

        int responseCode = connection.getResponseCode();
        if (responseCode == HttpURLConnection.HTTP_OK) {
            System.out.println("Data sent successfully");
        } else {
            System.out.println("Error sending data: " + responseCode);
        }
    }
}

在这个例子中，我们设置了请求头的`Content-Type`为`application/x-www-form-urlencoded`，然后将表单数据作为字符串字节流写入到连接的输出流中。