C/S通讯，互传文件

上传或者下载文件客户端：

package com.et.FileClient;

import java.io.DataOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.net.Socket;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;

public class FileClient extends Activity {
    /** Called when the activity is first created. */
	
    private TextView textView;
    private Button download;
    private Button upload;
    
    
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        textView=(TextView) findViewById(R.id.textview);
        download=(Button) findViewById(R.id.Button01);
        upload = (Button) findViewById(R.id.Button02);
        download.setOnClickListener(new OnClickListener() {
			
			public void onClick(View v) {
				// TODO Auto-generated method stub
			try
			{
				Socket s=new Socket("116.29.62.23",5554);
				InputStream is=s.getInputStream();
				if (is==null)
				{
					throw new RuntimeException("stream is null");
				}
				File myTempFile = new File("/data/data/com.et.FileClient","a.jpg");
				FileOutputStream fos = new FileOutputStream(myTempFile);
				byte buf[]=new byte[1024];
				while (true)
				{
					int num = is.read(buf);
					if (num<=0)
						break;
					fos.write(buf, 0, num);
				}
				is.close();
				s.close();
			}
        catch(Exception e)
        {
        	System.out.println("发生异常:"+e);
			e.printStackTrace();
        }
			}
		});
        
        upload.setOnClickListener(new View.OnClickListener() {
			
			public void onClick(View v) {
				// TODO Auto-generated method stub
				try
				{
					Socket s=new Socket("116.29.62.23",5554);
					File file = new File("/data/data/com.et.FileClient/image.jpg");
					FileInputStream fos = new FileInputStream(file);
					DataOutputStream out = new DataOutputStream(s.getOutputStream());
					byte[] buf = new byte[1024];
					int num = fos.read(buf);
					while (num!=-1)
					{
						out.write(buf, 0, num);
						out.flush();
						num=fos.read(buf);
					}
				}
				catch(Exception e)
				{
					
				}
			}
		});
    }
}

下载文件服务器端：

package com.et.FileClient;
import java.io.*;
import java.util.*;
import java.net.*;
public class FileDownServer {
public static void main(String[] args) throws Exception {

//创建文件流用来读取文件中的数据

File file = new File("a.jpg");

FileInputStream fos = new FileInputStream(file);
ServerSocket ss = new ServerSocket(5554);
//创建网络服务器接受客户请求
while (true)
{
	
	Socket client = ss.accept();
	System.out.println("accept");
	//创建网络输出流并提供数据包装器

	OutputStream netOut = client.getOutputStream();

	OutputStream doc = new DataOutputStream(
			new BufferedOutputStream(netOut));

	//创建文件读取缓冲区

	byte[] buf = new byte[2048];

	int num = fos.read(buf);
	while (num != (-1)) {//是否读完文件
		doc.write(buf, 0, num);//把文件数据写出网络缓冲区
		doc.flush();//刷新缓冲区把数据写往客户端
		num = fos.read(buf);//继续从文件中读取数据
	}
	fos.close();
	doc.close();
}
}


}

上传文件服务器端：

package com.et.FileClient;
import java.io.*;
import java.util.*;
import java.net.*;
public class FileUpServer {
public static void main(String[] args) throws Exception {

ServerSocket ss = new ServerSocket(5554);
//创建网络服务器接受客户请求
while (true)
{
	
	Socket s = ss.accept();
	System.out.println("accept");
	//创建网络输出流并提供数据包装器

	InputStream is=s.getInputStream();
	if (is==null)
	{
		throw new RuntimeException("stream is null");
	}
	File myTempFile = new File("image.jpg");
	FileOutputStream fos = new FileOutputStream(myTempFile);
	byte buf[]=new byte[1024];
	while (true)
	{
		int num = is.read(buf);
		if (num<=0)
			break;
		fos.write(buf, 0, num);
	}
		is.close();
		s.close();
}
}
}