如何在 HttpURLConnection 中向 Url 添加参数

Question

我正在尝试将 matchday 传递给 Http 连接的 URL。我知道我无法从 doInBackground 方法中的 EditText 获取值，所以我想在 onPreExecute 方法中获取值。然后我将变量添加到 URL，程序无法识别字符串。我在 StackOverflow 上看到您需要在执行方法中添加参数，但我真的没有得到那部分的解释。

有没有人知道如何将比赛日添加到在 EditText matchdayText 中输入的 URL？

提前致谢！ 罗伯尼克曼斯

代码：

    package ga.rndevelopment.footballpronostics;

    import android.os.AsyncTask;
    import android.os.Bundle;
    import android.support.v7.app.AppCompatActivity;
    import android.util.Log;
    import android.view.View;
    import android.widget.Button;
    import android.widget.EditText;
    import android.widget.ProgressBar;
    import android.widget.TextView;

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


    public class MainActivity extends AppCompatActivity {

    EditText matchdayText;
    TextView responseView;
    ProgressBar progressBar;
    static final String API_KEY = "HIDDEN";
    static final String API_URL = "http://api.football-data.org/v2/competitions/PL/matches/?matchday=";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        responseView = findViewById(R.id.responseView);
        matchdayText = findViewById(R.id.matchdayText);
        progressBar = findViewById(R.id.progressBar);

        Button queryButton = findViewById(R.id.queryButton);
        queryButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                new FetchData().execute();
            }
        });
    }

    class FetchData extends AsyncTask<Void, Void, String> {

        @Override
        protected void onPreExecute() {
            progressBar.setVisibility(View.VISIBLE);
            responseView.setText("");
            String matchDay = matchdayText.getText().toString();
            String apiUrl = API_URL + matchDay;
        }

        @Override
        protected String doInBackground(Void... params) {

            try {
                URL url = new URL(apiUrl);
                HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();

                urlConnection.addRequestProperty("X-Auth-Token", API_KEY);

                try {
                    BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(urlConnection.getInputStream()));
                    StringBuilder stringBuilder = new StringBuilder();
                    String line;
                    while ((line = bufferedReader.readLine()) != null) {
                        stringBuilder.append(line).append("\n");
                    }
                    bufferedReader.close();
                    return stringBuilder.toString();
                } finally {
                    urlConnection.disconnect();
                }
            } catch (Exception e) {
                Log.e("ERROR", e.getMessage(), e);
                return null;
            }
        }

        @Override
        protected void onPostExecute(String response) {
            if (response == null) {
                response = "THERE WAS AN ERROR";
            }
            progressBar.setVisibility(View.GONE);
            Log.i("INFO", response);
            responseView.setText(response);
        }
    }
}

Answer 1

首先使用 URL Connection.There 创建连接。 缓冲区写入器并在一个字符串中传递所有请求的数据 那里的缓冲区变量将涉及 URL 和 请求的参数及其值。请通过以下 示例示例

 URL url = new URL("give your URL ");
 URLConnection conn = url.openConnection();
 conn.setDoOutput(true);
 BufferedWriter out = new BufferedWriter(new OutputStreamWriter(conn.getOutputStream()));
        final StringBuilder reqstData = new StringBuilder(100);
        reqstData.append("&userId=").append(userId);
        reqstData.append("&roleId=").append(roleId);
        reqstData.append("&userName=").append(userName);
 out.write(reqstData);
 out.flush();
 BufferedReader in = new BufferedReader(new InputStreamReader(conn.getInputStream()));