I'm developing an Android application (client) and want it to connect with my Java server using TCP communication.
我正在开发一个Android应用程序（客户端），并希望它使用TCP通信与我的Java服务器连接。
I've done the code - simple program, client send a message and server echos it back - as below:
我已经完成了代码 - 简单的程序，客户端发送消息，服务器回复它 - 如下所示：
Server code:
服务器代码：
import java.net.*;
public class Server {
public static void main(String[] args) {
int nreq = 1;
try
{
ServerSocket sock = new ServerSocket (8080);
for (;;)
{
Socket newsock = sock.accept();
System.out.println("Creating thread ...");
Thread t = new ThreadHandler(newsock,nreq);
t.start();
}
}
catch (Exception e)
{
System.out.println("IO error " + e);
}
System.out.println("End!");
}
}
a Thread Handler code in the same project file of the server:
服务器的同一项目文件中的线程处理程序代码：
import java.io.*;
import java.net.*;
class ThreadHandler extends Thread {
Socket newsock;
int n;
ThreadHandler(Socket s, int v) {
newsock = s;
n = v;
}
public void run() {
try {
PrintWriter outp = new PrintWriter(newsock.getOutputStream(), true);
BufferedReader inp = new BufferedReader(new InputStreamReader(
newsock.getInputStream()));
outp.println("Hello :: enter QUIT to exit \n");
boolean more_data = true;
String line;
while (more_data) {
line = inp.readLine();
System.out.println("Message '" + line + "' echoed back to client.");
if (line == null) {
System.out.println("line = null");
more_data = false;
} else {
outp.println("From server: " + line + ". \n");
if (line.trim().equals("QUIT"))
more_data = false;
}
}
newsock.close();
System.out.println("Disconnected from client number: " + n);
} catch (Exception e) {
System.out.println("IO error " + e);
}
}
}
And this is the Client side (Android):
这是客户端（Android）：
package com.android.client;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.Socket;
import java.util.Scanner;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
public class Client extends Activity {
/** Called when the activity is first created. */
Scanner scanner = new Scanner(System.in);
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
final EditText msg = (EditText) findViewById(R.id.etMsg);
Button send = (Button) findViewById(R.id.bSend);
final TextView convo = (TextView) findViewById(R.id.tvConvo);
final TextView status = (TextView) findViewById(R.id.tvStatus);
try {
send.setOnClickListener(new View.OnClickListener() {
Socket s = new Socket("localhost", 8080);
String message = msg.getText().toString();
@Override
public void onClick(View v) {
status.setText("...");
PrintWriter outp = null;
BufferedReader inp = null;
status.setText("Established connection..");
String serverMsg = null;
try {
outp = new PrintWriter(s.getOutputStream(), true);
inp = new BufferedReader(new InputStreamReader(s.getInputStream()));
serverMsg = inp.readLine();
} catch (IOException e) {
e.printStackTrace();
}
convo.append(serverMsg + "\n");
if (message != null) {
if (msg.getText().toString().trim() == "QUIT") {
try {
s.close();
} catch (IOException e) {
e.printStackTrace();
}
status.setText("Disconnected from server.");
} else {
try {
convo.append(message + "\n");
outp.println(message);
serverMsg = inp.readLine();
convo.append(serverMsg + "\n");
} catch (IOException e) {
e.printStackTrace();
}
}
}
else
status.setText("Problem in connection..!");
}
});
} catch (IOException e) {
e.printStackTrace();
}
}
}
And this is the XML file:
这是XML文件：
<?xml version="1.0" encoding="utf-8" ?>
- <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent" android:orientation="vertical">
<TextView android:id="@+id/tvText" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Your message here:" />
- <EditText android:id="@+id/etMsg" android:layout_width="match_parent" android:layout_height="wrap_content" android:ems="10">
<requestFocus />
</EditText>
<TextView android:id="@+id/tvStatus" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Status..." android:textAppearance="?android:attr/textAppearanceSmall" />
<Button android:id="@+id/bSend" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Send" />
<TextView android:id="@+id/textView1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Conversation:" android:textAppearance="?android:attr/textAppearanceLarge" />
<TextView android:id="@+id/tvConvo" android:layout_width="fill_parent" android:layout_height="wrap_content" android:text="" />
</LinearLayout>
I tried running it, but nothing happens. When I click the button the TextView doesn't view the "Hello" message from the server.
我试过运行它，但没有任何反应。当我单击按钮时，TextView不会从服务器查看“Hello”消息。
2 个解决方案
#1
8
You connect with your Android client to localhost.
您将Android客户端连接到localhost。
Socket s = new Socket("localhost", 8080);
This would only work when your server is running on the Android device. But I think it is running on your PC. So, when you run your app on Android emulator, you can connect to 10.0.2.2 in order to contact the host. On a real device, you have to find out your servers IP address which can be reached by the Android device, e.g. via Wi-Fi.
这仅适用于您的服务器在Android设备上运行的情况。但我认为它在你的电脑上运行。因此，当您在Android模拟器上运行应用程序时，可以连接到10.0.2.2以联系主机。在真实设备上，您必须找到Android设备可以访问的服务器IP地址，例如：通过Wi-Fi。
#2
0
If your server is on Windows, type cmd in the Start menu search box and then type ipconfig at the command prompt. You will see something like IVP4 Address----- 192.168.0.101. you need to use this address and port number on your client.
如果您的服务器在Windows上，请在“开始”菜单搜索框中键入cmd，然后在命令提示符下键入ipconfig。您将看到类似IVP4地址----- 192.168.0.101的内容。您需要在客户端上使用此地址和端口号。
#1
8
You connect with your Android client to localhost.
您将Android客户端连接到localhost。
Socket s = new Socket("localhost", 8080);
This would only work when your server is running on the Android device. But I think it is running on your PC. So, when you run your app on Android emulator, you can connect to 10.0.2.2 in order to contact the host. On a real device, you have to find out your servers IP address which can be reached by the Android device, e.g. via Wi-Fi.
这仅适用于您的服务器在Android设备上运行的情况。但我认为它在你的电脑上运行。因此，当您在Android模拟器上运行应用程序时，可以连接到10.0.2.2以联系主机。在真实设备上，您必须找到Android设备可以访问的服务器IP地址，例如：通过Wi-Fi。
#2
0
If your server is on Windows, type cmd in the Start menu search box and then type ipconfig at the command prompt. You will see something like IVP4 Address----- 192.168.0.101. you need to use this address and port number on your client.
如果您的服务器在Windows上，请在“开始”菜单搜索框中键入cmd，然后在命令提示符下键入ipconfig。您将看到类似IVP4地址----- 192.168.0.101的内容。您需要在客户端上使用此地址和端口号。