java使用原生http发送application/x-www-form-urlencoded请求

使用Java的HttpURLConnection类来发送application/x-www-form-urlencoded请求。以下是一个示例代码：

import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLEncoder;

public class HttpUrlConnectionExample {
    public static void main(String[] args) throws Exception {
        String url = "http://www.example.com";
        URL obj = new URL(url);
        HttpURLConnection con = (HttpURLConnection) obj.openConnection();

        // 设置请求方法为POST
        con.setRequestMethod("POST");

        // 设置请求头
        con.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");

        // 设置POST参数
        String title = "test";
        String sub1 = "1";
        String sub2 = "2";
        String sub3 = "3";
        String urlParameters = "title=" + URLEncoder.encode(title, "UTF-8") +
                "&sub%5B%5D=" + URLEncoder.encode(sub1, "UTF-8") +
                "&sub%5B%5D=" + URLEncoder.encode(sub2, "UTF-8") +
                "&sub%5B%5D=" + URLEncoder.encode(sub3, "UTF-8");

        // 发送POST请求
        con.setDoOutput(true);
        DataOutputStream wr = new DataOutputStream(con.getOutputStream());
        wr.writeBytes(urlParameters);
        wr.flush();
        wr.close();

        // 获取响应结果
        int responseCode = con.getResponseCode();
        BufferedReader in = new BufferedReader(new InputStreamReader(con.getInputStream()));
        String inputLine;
        StringBuffer response = new StringBuffer();
        while ((inputLine = in.readLine()) != null) {
            response.append(inputLine);
        }
        in.close();

        // 打印响应结果
        System.out.println(response.toString());
    }
}