Android客户端未连接到Java服务器

Question

下面是我的服务器代码：

package com.SentientShadow;

import java.io.*;
import java.net.ServerSocket;
import java.net.Socket;

public class Server {
    public static void main(String[] args) {
        Thread thread = new Thread(){
            public void run() {
                System.out.println("Server has started and is listening...");
                try{
                    ServerSocket socket = new ServerSocket(6879);
                    while (true){
                        Socket connection = socket.accept();
                        DataInputStream input = new DataInputStream(connection.getInputStream());
                        System.out.println("Received from client: " + input.readUTF());
                        input.close();
                        connection.close();
                    }
                }catch(IOException e){
                    System.out.println("problem accepting connection");
                }
            }   
        };
        thread.start();
    }
}

下面是我的客户端活动代码：

package com.SentientShadow;

import java.io.DataOutputStream;
import java.io.IOException;
import java.net.InetAddress;
import java.net.Socket;
import java.net.UnknownHostException;

import android.support.v7.app.ActionBarActivity;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
import android.os.Bundle;

public class Client extends ActionBarActivity implements OnClickListener {
    private EditText etMessage;
    private Button bSend;

    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_client);
        etMessage = (EditText)findViewById(R.id.etMessage);
        bSend = (Button)findViewById(R.id.bSend);
        bSend.setOnClickListener(this);
    }

    public void onClick(View view) {
        Thread thread = new Thread(){
            public void run() {
                try {
                    Socket connection = new Socket("127.0.0.1", 6789);
                    DataOutputStream output = new DataOutputStream(connection.getOutputStream());
                    output.writeUTF(etMessage.getText().toString());
                    output.flush();
                    output.close();
                    connection.close();
                } catch (UnknownHostException e) {
                    System.out.println("problem connecting to specified address");
                } catch (IOException e) {
                    System.out.println("problem connecting to port");
                }
            }
        };
        thread.start();
        Toast.makeText(this, "Message has been sent!", Toast.LENGTH_SHORT).show();
    }
}

以下是客户端活动的xml布局文件：

<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="com.SentientShadow.Client" >

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Enter message:" />

    <EditText
        android:id="@+id/etMessage"
        android:layout_width="wrap_content"
        android:layout_height="100dp"
        android:layout_alignLeft="@+id/textView1"
        android:layout_below="@+id/textView1"
        android:layout_marginTop="14dp"
        android:ems="10" />

    <Button
        android:id="@+id/bSend"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/editText1"
        android:layout_below="@+id/editText1"
        android:text="Send" />

</RelativeLayout>

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.SentientShadow"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="19" />
    <uses-permission android:name="android.permission.INTERNET"/>
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="Client"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN"/>
                <category android:name="android.intent.category.LAUNCHER"/>
            </intent-filter>
        </activity>
    </application>

</manifest>

因此，我开始认为这不是连接端口的问题，而是应用程序的android客户端的问题。但我想不出有什么问题。

顺便说一下，当我试图发送消息时，运行客户端的手机和运行服务器的笔记本电脑都连接到了同一个网络。

Answer 1

好吧，多亏了GreenApps的建议，我终于找到了问题所在。基本上，结果是防火墙阻塞了到我计算机上的java平台的任何传入连接。

要解决此问题,请执行以下操作：

1. 打开“控制面板”并搜索windows防火墙
2. 在左侧的“具有高级安全性的Windows防火墙”对话框中，单击“入站规则”
3. 浏览并查看哪些应用程序被阻止接收连接
4. 选择要允许入站连接的应用程序，然后右键单击它
5. 选择“属性”并按“允许连接”或“允许连接（如果安全）”