java - 在 Android 中发送和接收 json 对象

Question

我目前正在使用一个可以访问在线游戏的应用程序来获取我的帐户信息。我需要使用 JSON 与服务器通信。我使用以下代码尝试与服务器通信，但服务器没有响应。我还注意到 httpclient 和其他一些流行的类已被弃用，我找不到一些合适的教程来教我这个主题。感谢您的帮助。

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="deardanielxd.travain2.MainActivity">

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:textAppearance="?android:attr/textAppearanceSmall"
    android:text="Username : "
    android:id="@+id/Username_Lbl"
    android:layout_alignParentTop="true"
    android:layout_alignParentStart="true"
    android:editable="true"
    android:minHeight="20dp"
    android:layout_alignBottom="@+id/Username_Field"
    android:layout_toStartOf="@+id/Username_Field"
    android:layout_alignEnd="@+id/Password_Lbl" />

<EditText
    android:layout_width="wrap_content"
    android:layout_height = "40dp"
    android:textAppearance="?android:attr/textAppearanceSmall"
    android:id="@+id/Username_Field"
    android:editable="true"
    android:contextClickable="true"
    android:textIsSelectable="true"
    android:enabled="true"
    android:focusable="true"
    android:clickable="true"
    android:inputType="text"
    android:minHeight="40dp"
    android:layout_alignParentTop="true"
    android:layout_alignEnd="@+id/Load_Btn"
    android:layout_toEndOf="@+id/Password_Lbl" />

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:textAppearance="?android:attr/textAppearanceSmall"
    android:text="Password : "
    android:id="@+id/Password_Lbl"
    android:layout_below="@+id/Username_Lbl"
    android:layout_alignParentStart="true"
    android:minHeight="20dp"
    android:layout_alignBottom="@+id/Password_Field" />

<EditText
    android:layout_width="wrap_content"
    android:layout_height="40dp"
    android:textAppearance="?android:attr/textAppearanceSmall"
    android:id="@+id/Password_Field"
    android:password="true"
    android:editable="true"
    android:textIsSelectable="true"
    android:enabled="true"
    android:focusable="true"
    android:contextClickable="true"
    android:clickable="true"
    android:inputType="text"
    android:minHeight="40dp"
    android:layout_below="@+id/Username_Field"
    android:layout_alignParentEnd="true"
    android:layout_alignStart="@+id/Username_Field" />

<Button
    style="?android:attr/buttonStyleSmall"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Load"
    android:id="@+id/Load_Btn"
    android:layout_alignParentEnd="true"
    android:layout_alignBottom="@+id/spinner"
    android:layout_below="@+id/Password_Field" />

<Spinner
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:id="@+id/spinner"
    android:spinnerMode="dropdown"
    android:layout_alignParentStart="true"
    android:layout_toStartOf="@+id/Load_Btn"
    android:layout_below="@+id/Password_Lbl" />

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:id="@+id/SysMsg"
    android:layout_alignParentStart="true"
    android:layout_alignParentBottom="true"
    android:layout_alignParentEnd="true"
    android:text="System : "
    android:textColor="#FF0000" />

<ScrollView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:id="@+id/scrollView"
    android:layout_below="@+id/spinner"
    android:layout_alignParentStart="true"
    android:layout_above="@+id/SysMsg"
    android:layout_alignParentEnd="true" >

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/OutPut"
        android:enabled="true" />
</ScrollView>

主 Activity .java

package deardanielxd.travain2;

import android.content.Context;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.os.AsyncTask;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Spinner;
import android.widget.TextView;
import org.json.JSONObject;
import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLEncoder;


public class MainActivity extends AppCompatActivity {

    Spinner spinner;
    EditText Username, Password;
    Button Load_Btn;
    TextView Main_Output;
    TextView Sys_Output;
    String server = "";
    boolean debug = true;
    PlayerInfo curr = new PlayerInfo();

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

        SetupGadget();
        attachListener();

    }

    private void SetupGadget() {
        spinner = (Spinner) findViewById(R.id.spinner);
        Username = (EditText) findViewById(R.id.Username_Field);
        Password = (EditText) findViewById(R.id.Password_Field);
        Load_Btn = (Button) findViewById(R.id.Load_Btn);
        Main_Output = (TextView) findViewById(R.id.OutPut);
        Sys_Output = (TextView) findViewById(R.id.SysMsg);

        ArrayAdapter adapter = new ArrayAdapter<String>(this,android.R.layout.simple_spinner_item,Constants.Servers);
        spinner.setAdapter(adapter);
    }

    private void attachListener() {
        Load_Btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (debug) {
                    MainOutput( "Username : " + Username.getText());
                    MainOutput( "Password : " + Password.getText());
                    MainOutput( "Server : " + server);
                    MainOutput( "Internet Connection : " + (InternetAccess()?"Yes":"No"));
                    MainOutput( "" );
                }

                new test(MainActivity.this).execute();

            }
        });

        spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
            @Override
            public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
                server = parent.getSelectedItem().toString();
            }

            @Override
            public void onNothingSelected(AdapterView<?> parent) {

            }
        });

    }

    private void SystemOutput(String output) {
        Sys_Output.setText("System : " + output);
    }

    public void MainOutput(String output) {
        Main_Output.append("\n" + output);
    }

    private boolean InternetAccess() {
        ConnectivityManager cm =
                (ConnectivityManager)this.getSystemService(Context.CONNECTIVITY_SERVICE);

        NetworkInfo activeNetwork = cm.getActiveNetworkInfo();
        return activeNetwork != null &&
                activeNetwork.isConnectedOrConnecting();

    }

    public class test extends AsyncTask<Void, Void, Void>

    {
        private MainActivity MA;

        test(MainActivity ma) {
            MA = ma;
        }

        @Override
        protected Void doInBackground(Void... n) {

            try {
                URL url = new URL("http://"+MA.server+"/api/external.php");
                HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();

                urlConnection.setDoOutput(true);
                urlConnection.setRequestProperty("Content-Type","application/json");
                urlConnection.setRequestProperty("Host", "android.schoolportal.gr");
                urlConnection.setRequestMethod("POST");
                urlConnection.setUseCaches(false);
                urlConnection.connect();

                OutputStream printout = new DataOutputStream(urlConnection.getOutputStream ());
                printout.write(URLEncoder.encode(this.getObj().toString(),"UTF-8").getBytes());
                printout.flush ();
                printout.close ();

                try {
                    urlConnection.setRequestMethod("GET");
                    urlConnection.setDoInput(true);
                    InputStream in = new BufferedInputStream(urlConnection.getInputStream());
                    BufferedReader r = new BufferedReader(new InputStreamReader(in));
                    StringBuilder total = new StringBuilder(in.available());
                    String line;
                    while ((line = r.readLine()) != null) {
                        total.append(line).append('\n');
                    }
                    MA.MainOutput(total.toString());
                    MA.MainOutput("End of Doc");
                } finally {
                    urlConnection.disconnect();
                    return null;
                }
            } catch (java.net.MalformedURLException e) {

            } catch (java.io.IOException e) {

            };
            return null;

        }

        private JSONObject getObj() {

            JSONObject jobj = new JSONObject();
            try {
                jobj.put("email","funckybuggy@gmail.com");
                jobj.put("siteName","EasyTravian");
                jobj.put("sitUrl","testing.com");
                jobj.put("public",false);
            } catch (org.json.JSONException e) {

            }
            return jobj;

        }

    }

    public PlayerInfo getCurrentPlayerInfo() {
        return this.curr;
    }

    public void UpdateCurr() {
        this.curr.Username = this.Username.getText().toString();
        this.curr.Password = this.Password.getText().toString();
        this.curr.Server = this.server;
    }

    }

常量.java

public class Constants {
public static final String[] Servers = {
    "ts1.travian.hk",
    "ts2.travian.hk",
    "ts20.travian.hk",
    "tx3.travian.hk",
    "ts4.travian.hk",
    "ts19.travian.hk",
    "ts3.travian.hk",
    "ts6.travian.hk",
    "ts5.travian.hk"
};

}

Answer 1

我认为您不应该对消息正文进行编码。它被称为“URLEncoder”的原因是因为它用于对 URL 进行编码，但这是您的消息的正文。

此外，您拥有的内部 try block 是多余的，您还应该在请求中间将请求方法更改为 GET。

无需刷新字节。

请记住，对于 POST 请求，在您使用 InputStream 读取响应之前，不会发送任何内容。