java发送短信之AT指令

在Java中发送短信可以通过AT指令来实现。下面是一个示例代码：

import java.io.*;
import java.util.*;

public class SMS {

    public static void main(String[] args) throws Exception {
        String recipient = "手机号码";
        String message = "短信内容";

        String username = "用户名";
        String password = "密码";

        String requestUrl  = "http://www.smsadmin.cn/smsmarketing/wwwroot/api/post_send/";
        String params = "un=" + username + "&pwd=" + password + "&mobile=" + recipient + "&msg=" + message;

        URL url = new URL(requestUrl);
        HttpURLConnection conn = (HttpURLConnection) url.openConnection();
        conn.setRequestMethod("POST");
        conn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
        conn.setDoOutput(true);

        OutputStreamWriter writer = new OutputStreamWriter(conn.getOutputStream());
        writer.write(params);
        writer.flush();

        BufferedReader reader = new BufferedReader(new InputStreamReader(conn.getInputStream()));
        String line;
        while ((line = reader.readLine()) != null) {
            System.out.println(line);
        }
        reader.close();
        writer.close();
    }
}

需要注意的是，这里使用的是第三方短信平台提供的API接口，需要先在该平台注册账号并获取相关参数（如用户名、密码、请求URL等）。在发送短信时，需要将手机号码和短信内容拼接成请求参数，然后通过POST请求发送到短信平台的服务器上。