java调用http接口，并在调用前传用户名和密码参数

你可以使用Java中的HttpURLConnection类来调用http接口，并在调用前传用户名和密码参数。以下是一个示例代码：

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.Base64;

public class HttpUrlConnectionExample {
    public static void main(String[] args) {
        try {
            String username = "your_username";
            String password = "your_password";
            String url = "http://example.com/api";

            URL obj = new URL(url);
            HttpURLConnection con = (HttpURLConnection) obj.openConnection();

            // set request method
            con.setRequestMethod("GET");

            // set basic authentication header
            String auth = username + ":" + password;
            byte[] encodedAuth = Base64.getEncoder().encode(auth.getBytes());
            String authHeaderValue = "Basic " + new String(encodedAuth);
            con.setRequestProperty("Authorization", authHeaderValue);

            // read response
            BufferedReader in = new BufferedReader(
                    new InputStreamReader(con.getInputStream()));
            String inputLine;
            StringBuilder response = new StringBuilder();
            while ((inputLine = in.readLine()) != null) {
                response.append(inputLine);
            }
            in.close();

            // print response
            System.out.println(response.toString());
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

在这个示例中，我们首先设置了要调用的API的URL、用户名和密码。然后我们使用Java的Base64类来编码用户名和密码，以便将其添加到http请求标头中。最后，我们使用HttpURLConnection类来执行GET请求，并读取响应。