在localhost, Android Studio中从PHP读取JSON时连接被拒绝

我正在尝试连接到我的本地主机服务器上的一个php工作正常，但我无法读取那里的内容。

package com.example.klaussius.probandoconexionservidor;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import serverDataRead.ReadUsers;
public class Principal extends AppCompatActivity {
    TextView tvText;
    Button btGetInfo;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_principal);
        // TextView for our text
        tvText = (TextView)findViewById(R.id.tvText);
        // Button to get text
        btGetInfo = (Button)findViewById(R.id.btGetInfo);
        btGetInfo.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                new leerDatos().execute();
            }
        });
    }
private class leerDatos extends AsyncTask<String,Void,String> {
    @Override
    protected String doInBackground(String... strings) {
        ReadUsers reader = new ReadUsers();
        return reader.readUsers();
    }
    @Override
    protected void onPostExecute(String s) {
        super.onPostExecute(s);
        tvText.setText(s);
        }
    }
}

方法readUsers在readUsers:

package serverDataRead;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
public class ReadUsers {
    public String texto;
    public String readUsers(){
        try {
            String link = "http://127.0.0.1/api/usersQuery.php";
            URL url = new URL(link);
            HttpURLConnection con = HttpURLConnection)url.openConnection();
            BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(con.getInputStream()));
            texto = bufferedReader.readLine();
        } catch (Exception e) {
            texto = "Fail!";
            e.printStackTrace();
        } finally {
            return texto;
        }
    }
}

布局:

<LinearLayout
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/btGetInfo"
        android:text="@string/getText" />
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/tvText" />
</LinearLayout>

我得到的错误:W/系统。错误:java.net.ConnectException: Connection refused

提前感谢您的帮助。