原文:http://blog.csdn.net/shimiso/article/details/8529633
什么是Socket?
所谓Socket通常也称作“套接字”,用于描述IP地址和端口,是一个通信连的句柄,应用程序通常通过“套接字”向网络发送请求或者应答网络请求,它就是网络通信过程中端点的抽象表示。它主要包括以下两个协议:
TCP (Transmission Control Protocol 传输控制协议):传输控制协议,提供的是面向连接、可靠的字节流服务。当客户和服务器彼此交换数据前,必须先在双方之间建立一个TCP连接,之后才能传输数据。TCP提供超时重发,丢弃重复数据,检验数据,流量控制等功能,保证数据能从一端传到另一端。
UDP (User Datagram Protocl 用户数据报协议):用户数据报协议,是一个简单的面向数据报的运输层协议。UDP不提供可靠性,它只是把应用程序传给IP层的数据报发送出去,但是并不能保证它们能到达目的地。由于UDP在传输数据报前不用在客户和服务器之间建立一个连接,且没有超时重发等机制,故而传输速度很快。
详细解说如下:
TCP传输和UDP不一样,TCP传输是流式的,必须先建立连接,然后数据流沿已连接的线路(虚电路)传输。因此TCP的数据流不会像UDP数据报一样,每个数据报都要包含目标地址和端口,因为每个数据报要单独路由。TCP传输则只需要在建立连接时指定目标地址和端口就可以了。
形象的讲,TCP就像打电话,UDP就像发电报。宏观上来看UDP是不分客户端和服务端的。通信双方是平等的。微观上来讲只相对一个报文,发送端是客户端,监听端是服务端。发送端把数据报发给路由器就像把电报发给了邮局,后面的事情就是发送者无法控制,也无从知晓的了。所以说是不可靠的,可能会出现报文丢失而无从知晓。就像每张电报都要有收件人一样,每个数据报都要有目的地址和端口。
而TCP每次连接都是分客户端和服务端的。连接的发起者(相当与拨号打电话的人)是客户端,监听者(相当于在电话边等着接电话的人)是服务端。发起者指定要连接的服务器地址和端口(相当于拨号),监听者通过和发起者三次握手建立连接(相当于听到电话响去接电话)。建立连接后双方可以互相发送和接受数据(打电话)。
Java如何操作Socket?
值得一提的是,Java分别为TCP和UDP提供了相应的类,TCP是java.net中提供了两个类Socket和ServerSocket,分别用来表示双向连接的客户端和服务端。这是两个封装得非常好的类,使用起来很方便!UDP是java.net.DatagramSocket.
127.0.0.1是回路地址,用于测试,相当于localhost本机地址,没有网卡,不设DNS都可以访问,端口地址在0~65535之间,其中0~1023之间的端口是用于一些知名的网络服务和应用,用户的普通网络应用程序应该使用1024以上的端口.
Socket通信模型如下:
如果大家对Java Socket编程还有模糊的地方抓紧温习(http://blog.csdn.net/shimiso/article/details/8529941),本文不在此赘述,下面我们以最常用的TCP协议举例:
服务器,使用ServerSocket监听指定的端口,端口可以随意指定(由于1024以下的端口通常属于保留端口,在一些操作系统中不可以随意使用,所以建议使用大于1024的端口),等待客户连接请求,客户连接后,会话产生;在完成会话后,关闭连接。
客户端,使用Java socket通信对网络上某一个服务器的某一个端口发出连接请求,一旦连接成功,打开会话;会话完成后,关闭Socket。客户端不需要指定打开的端口,通常临时的、动态的分配一个1024以上的端口。
TCP网络连接模型:
Android客户端程序代分析:
- UploadActivity.java
- package com.android.upload;
- import java.io.File;
- import java.io.OutputStream;
- import java.io.PushbackInputStream;
- import java.io.RandomAccessFile;
- import java.net.Socket;
- import android.app.Activity;
- import android.os.Bundle;
- import android.os.Environment;
- import android.os.Handler;
- import android.os.Message;
- import android.view.View;
- import android.view.View.OnClickListener;
- import android.widget.Button;
- import android.widget.EditText;
- import android.widget.ProgressBar;
- import android.widget.TextView;
- import android.widget.Toast;
- import com.android.service.UploadLogService;
- import com.android.socket.utils.StreamTool;
- public class UploadActivity extends Activity {
- private EditText filenameText;
- private TextView resulView;
- private ProgressBar uploadbar;
- private UploadLogService logService;
- private boolean start=true;
- private Handler handler = new Handler(){
- @Override
- public void handleMessage(Message msg) {
- int length = msg.getData().getInt("size");
- uploadbar.setProgress(length);
- float num = (float)uploadbar.getProgress()/(float)uploadbar.getMax();
- int result = (int)(num * 100);
- resulView.setText(result+ "%");
- if(uploadbar.getProgress()==uploadbar.getMax()){
- Toast.makeText(UploadActivity.this, R.string.success, 1).show();
- }
- }
- };
- @Override
- public void onCreate(Bundle savedInstanceState) {
- super.onCreate(savedInstanceState);
- setContentView(R.layout.main);
- logService = new UploadLogService(this);
- filenameText = (EditText)this.findViewById(R.id.filename);
- uploadbar = (ProgressBar) this.findViewById(R.id.uploadbar);
- resulView = (TextView)this.findViewById(R.id.result);
- Button button =(Button)this.findViewById(R.id.button);
- Button button1 =(Button)this.findViewById(R.id.stop);
- button1 .setOnClickListener(new OnClickListener() {
- @Override
- public void onClick(View v) {
- start=false;
- }
- });
- button.setOnClickListener(new View.OnClickListener() {
- @Override
- public void onClick(View v) {
- start=true;
- String filename = filenameText.getText().toString();
- if(Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){
- File uploadFile = new File(Environment.getExternalStorageDirectory(), filename);
- if(uploadFile.exists()){
- uploadFile(uploadFile);
- }else{
- Toast.makeText(UploadActivity.this, R.string.filenotexsit, 1).show();
- }
- }else{
- Toast.makeText(UploadActivity.this, R.string.sdcarderror, 1).show();
- }
- }
- });
- }
- /**
- * 上传文件
- * @param uploadFile
- */
- private void uploadFile(final File uploadFile) {
- new Thread(new Runnable() {
- @Override
- public void run() {
- try {
- uploadbar.setMax((int)uploadFile.length());
- String souceid = logService.getBindId(uploadFile);
- String head = "Content-Length="+ uploadFile.length() + ";filename="+ uploadFile.getName() + ";sourceid="+
- (souceid==null? "" : souceid)+"\r\n";
- Socket socket = new Socket("192.168.1.78",7878);
- OutputStream outStream = socket.getOutputStream();
- outStream.write(head.getBytes());
- PushbackInputStream inStream = new PushbackInputStream(socket.getInputStream());
- String response = StreamTool.readLine(inStream);
- String[] items = response.split(";");
- String responseid = items[0].substring(items[0].indexOf("=")+1);
- String position = items[1].substring(items[1].indexOf("=")+1);
- if(souceid==null){//代表原来没有上传过此文件,往数据库添加一条绑定记录
- logService.save(responseid, uploadFile);
- }
- RandomAccessFile fileOutStream = new RandomAccessFile(uploadFile, "r");
- fileOutStream.seek(Integer.valueOf(position));
- byte[] buffer = new byte[1024];
- int len = -1;
- int length = Integer.valueOf(position);
- while(start&&(len = fileOutStream.read(buffer)) != -1){
- outStream.write(buffer, 0, len);
- length += len;
- Message msg = new Message();
- msg.getData().putInt("size", length);
- handler.sendMessage(msg);
- }
- fileOutStream.close();
- outStream.close();
- inStream.close();
- socket.close();
- if(length==uploadFile.length()) logService.delete(uploadFile);
- } catch (Exception e) {
- e.printStackTrace();
- }
- }
- }).start();
- }
- }
- StreamTool.java
- package com.android.socket.utils;
- import java.io.ByteArrayOutputStream;
- import java.io.File;
- import java.io.FileOutputStream;
- import java.io.IOException;
- import java.io.InputStream;
- import java.io.PushbackInputStream;
- public class StreamTool {
- public static void save(File file, byte[] data) throws Exception {
- FileOutputStream outStream = new FileOutputStream(file);
- outStream.write(data);
- outStream.close();
- }
- public static String readLine(PushbackInputStream in) throws IOException {
- char buf[] = new char[128];
- int room = buf.length;
- int offset = 0;
- int c;
- loop: while (true) {
- switch (c = in.read()) {
- case -1:
- case '\n':
- break loop;
- case '\r':
- int c2 = in.read();
- if ((c2 != '\n') && (c2 != -1)) in.unread(c2);
- break loop;
- default:
- if (--room < 0) {
- char[] lineBuffer = buf;
- buf = new char[offset + 128];
- room = buf.length - offset - 1;
- System.arraycopy(lineBuffer, 0, buf, 0, offset);
- }
- buf[offset++] = (char) c;
- break;
- }
- }
- if ((c == -1) && (offset == 0)) return null;
- return String.copyValueOf(buf, 0, offset);
- }
- /**
- * 读取流
- * @param inStream
- * @return 字节数组
- * @throws Exception
- */
- public static byte[] readStream(InputStream inStream) throws Exception{
- ByteArrayOutputStream outSteam = new ByteArrayOutputStream();
- byte[] buffer = new byte[1024];
- int len = -1;
- while( (len=inStream.read(buffer)) != -1){
- outSteam.write(buffer, 0, len);
- }
- outSteam.close();
- inStream.close();
- return outSteam.toByteArray();
- }
- }
- UploadLogService.java
- package com.android.service;
- import java.io.File;
- import android.content.Context;
- import android.database.Cursor;
- import android.database.sqlite.SQLiteDatabase;
- public class UploadLogService {
- private DBOpenHelper dbOpenHelper;
- public UploadLogService(Context context){
- this.dbOpenHelper = new DBOpenHelper(context);
- }
- public void save(String sourceid, File uploadFile){
- SQLiteDatabase db = dbOpenHelper.getWritableDatabase();
- db.execSQL("insert into uploadlog(uploadfilepath, sourceid) values(?,?)",
- new Object[]{uploadFile.getAbsolutePath(),sourceid});
- }
- public void delete(File uploadFile){
- SQLiteDatabase db = dbOpenHelper.getWritableDatabase();
- db.execSQL("delete from uploadlog where uploadfilepath=?", new Object[]{uploadFile.getAbsolutePath()});
- }
- public String getBindId(File uploadFile){
- SQLiteDatabase db = dbOpenHelper.getReadableDatabase();
- Cursor cursor = db.rawQuery("select sourceid from uploadlog where uploadfilepath=?",
- new String[]{uploadFile.getAbsolutePath()});
- if(cursor.moveToFirst()){
- return cursor.getString(0);
- }
- return null;
- }
- }
- DBOpenHelper.java
- package com.android.service;
- import android.content.Context;
- import android.database.sqlite.SQLiteDatabase;
- import android.database.sqlite.SQLiteOpenHelper;
- public class DBOpenHelper extends SQLiteOpenHelper {
- public DBOpenHelper(Context context) {
- super(context, "upload.db", null, 1);
- }
- @Override
- public void onCreate(SQLiteDatabase db) {
- db.execSQL("CREATE TABLE uploadlog (_id integer primary key autoincrement, uploadfilepath varchar(100), sourceid varchar(10))");
- }
- @Override
- public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
- db.execSQL("DROP TABLE IF EXISTS uploadlog");
- onCreate(db);
- }
- }
- main.xml
- <?xml version="1.0" encoding="utf-8"?>
- <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
- android:orientation="vertical"
- android:layout_width="fill_parent"
- android:layout_height="fill_parent"
- >
- <TextView
- android:layout_width="fill_parent"
- android:layout_height="wrap_content"
- android:text="@string/filename"
- />
- <EditText
- android:layout_width="fill_parent"
- android:layout_height="wrap_content"
- android:text="022.jpg"
- android:id="@+id/filename"
- />
- <Button
- android:layout_width="wrap_content"
- android:layout_height="wrap_content"
- android:text="@string/button"
- android:id="@+id/button"
- />
- <Button
- android:layout_width="wrap_content"
- android:layout_height="wrap_content"
- android:text="暂停"
- android:id="@+id/stop"
- />
- <ProgressBar
- android:layout_width="fill_parent"
- android:layout_height="20px"
- style="?android:attr/progressBarStyleHorizontal"
- android:id="@+id/uploadbar"
- />
- <TextView
- android:layout_width="fill_parent"
- android:layout_height="wrap_content"
- android:gravity="center"
- android:id="@+id/result"
- />
- </LinearLayout>
- AndroidManifest.xml
- <?xml version="1.0" encoding="utf-8"?>
- <manifest xmlns:android="http://schemas.android.com/apk/res/android"
- package="com.android.upload"
- android:versionCode="1"
- android:versionName="1.0" >
- <uses-sdk android:minSdkVersion="8" />
- <application
- android:icon="@drawable/ic_launcher"
- android:label="@string/app_name" >
- <activity
- android:name=".UploadActivity"
- 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>
- <!-- 访问网络的权限 -->
- <uses-permission android:name="android.permission.INTERNET"/>
- <!-- 在SDCard中创建与删除文件权限 -->
- <uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS"/>
- <!-- 往SDCard写入数据权限 -->
- <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
- </manifest>
Java服务端:
- SocketServer.javapackage com.android.socket.server;
- import java.io.File;
- import java.io.FileInputStream;
- import java.io.FileOutputStream;
- import java.io.IOException;
- import java.io.OutputStream;
- import java.io.PushbackInputStream;
- import java.io.RandomAccessFile;
- import java.net.ServerSocket;
- import java.net.Socket;
- import java.text.SimpleDateFormat;
- import java.util.Date;
- import java.util.HashMap;
- import java.util.Map;
- import java.util.Properties;
- import java.util.concurrent.ExecutorService;
- import java.util.concurrent.Executors;
- import com.android.socket.utils.StreamTool;
- public class SocketServer {
- private String uploadPath="D:/uploadFile/";
- private ExecutorService executorService;// 线程池
- private ServerSocket ss = null;
- private int port;// 监听端口
- private boolean quit;// 是否退出
- private Map<Long, FileLog> datas = new HashMap<Long, FileLog>();// 存放断点数据,最好改为数据库存放
- public SocketServer(int port) {
- this.port = port;
- // 初始化线程池
- executorService = Executors.newFixedThreadPool(Runtime.getRuntime()
- .availableProcessors() * 50);
- }
- // 启动服务
- public void start() throws Exception {
- ss = new ServerSocket(port);
- while (!quit) {
- Socket socket = ss.accept();// 接受客户端的请求
- // 为支持多用户并发访问,采用线程池管理每一个用户的连接请求
- executorService.execute(new SocketTask(socket));// 启动一个线程来处理请求
- }
- }
- // 退出
- public void quit() {
- this.quit = true;
- try {
- ss.close();
- } catch (IOException e) {
- e.printStackTrace();
- }
- }
- public static void main(String[] args) throws Exception {
- SocketServer server = new SocketServer(7878);
- server.start();
- }
- private class SocketTask implements Runnable {
- private Socket socket;
- public SocketTask(Socket socket) {
- this.socket = socket;
- }
- @Override
- public void run() {
- try {
- System.out.println("accepted connenction from "
- + socket.getInetAddress() + " @ " + socket.getPort());
- PushbackInputStream inStream = new PushbackInputStream(
- socket.getInputStream());
- // 得到客户端发来的第一行协议数据:Content-Length=143253434;filename=xxx.3gp;sourceid=
- // 如果用户初次上传文件,sourceid的值为空。
- String head = StreamTool.readLine(inStream);
- System.out.println(head);
- if (head != null) {
- // 下面从协议数据中读取各种参数值
- String[] items = head.split(";");
- String filelength = items[0].substring(items[0].indexOf("=") + 1);
- String filename = items[1].substring(items[1].indexOf("=") + 1);
- String sourceid = items[2].substring(items[2].indexOf("=") + 1);
- Long id = System.currentTimeMillis();
- FileLog log = null;
- if (null != sourceid && !"".equals(sourceid)) {
- id = Long.valueOf(sourceid);
- log = find(id);//查找上传的文件是否存在上传记录
- }
- File file = null;
- int position = 0;
- if(log==null){//如果上传的文件不存在上传记录,为文件添加跟踪记录
- String path = new SimpleDateFormat("yyyy/MM/dd/HH/mm").format(new Date());
- File dir = new File(uploadPath+ path);
- if(!dir.exists()) dir.mkdirs();
- file = new File(dir, filename);
- if(file.exists()){//如果上传的文件发生重名,然后进行改名
- filename = filename.substring(0, filename.indexOf(".")-1)+ dir.listFiles().length+ filename.substring(filename.indexOf("."));
- file = new File(dir, filename);
- }
- save(id, file);
- }else{// 如果上传的文件存在上传记录,读取上次的断点位置
- file = new File(log.getPath());//从上传记录中得到文件的路径
- if(file.exists()){
- File logFile = new File(file.getParentFile(), file.getName()+".log");
- if(logFile.exists()){
- Properties properties = new Properties();
- properties.load(new FileInputStream(logFile));
- position = Integer.valueOf(properties.getProperty("length"));//读取断点位置
- }
- }
- }
- OutputStream outStream = socket.getOutputStream();
- String response = "sourceid="+ id+ ";position="+ position+ "\r\n";
- //服务器收到客户端的请求信息后,给客户端返回响应信息:sourceid=1274773833264;position=0
- //sourceid由服务生成,唯一标识上传的文件,position指示客户端从文件的什么位置开始上传
- outStream.write(response.getBytes());
- RandomAccessFile fileOutStream = new RandomAccessFile(file, "rwd");
- if(position==0) fileOutStream.setLength(Integer.valueOf(filelength));//设置文件长度
- fileOutStream.seek(position);//移动文件指定的位置开始写入数据
- byte[] buffer = new byte[1024];
- int len = -1;
- int length = position;
- while( (len=inStream.read(buffer)) != -1){//从输入流中读取数据写入到文件中
- fileOutStream.write(buffer, 0, len);
- length += len;
- Properties properties = new Properties();
- properties.put("length", String.valueOf(length));
- FileOutputStream logFile = new FileOutputStream(new File(file.getParentFile(), file.getName()+".log"));
- properties.store(logFile, null);//实时记录文件的最后保存位置
- logFile.close();
- }
- if(length==fileOutStream.length()) delete(id);
- fileOutStream.close();
- inStream.close();
- outStream.close();
- file = null;
- }
- } catch (Exception e) {
- e.printStackTrace();
- } finally {
- try {
- if(socket != null && !socket.isClosed()) socket.close();
- } catch (IOException e) {}
- }
- }
- }
- public FileLog find(Long sourceid) {
- return datas.get(sourceid);
- }
- // 保存上传记录
- public void save(Long id, File saveFile) {
- // 日后可以改成通过数据库存放
- datas.put(id, new FileLog(id, saveFile.getAbsolutePath()));
- }
- // 当文件上传完毕,删除记录
- public void delete(long sourceid) {
- if (datas.containsKey(sourceid))
- datas.remove(sourceid);
- }
- private class FileLog {
- private Long id;
- private String path;
- public FileLog(Long id, String path) {
- super();
- this.id = id;
- this.path = path;
- }
- public Long getId() {
- return id;
- }
- public void setId(Long id) {
- this.id = id;
- }
- public String getPath() {
- return path;
- }
- public void setPath(String path) {
- this.path = path;
- }
- }
- }
- ServerWindow.javapackage com.android.socket.server;
- import java.awt.BorderLayout;
- import java.awt.Frame;
- import java.awt.Label;
- import java.awt.event.WindowEvent;
- import java.awt.event.WindowListener;
- public class ServerWindow extends Frame{
- private SocketServer server;
- private Label label;
- public ServerWindow(String title){
- super(title);
- server = new SocketServer(7878);
- label = new Label();
- add(label, BorderLayout.PAGE_START);
- label.setText("服务器已经启动");
- this.addWindowListener(new WindowListener() {
- @Override
- public void windowOpened(WindowEvent e) {
- new Thread(new Runnable() {
- @Override
- public void run() {
- try {
- server.start();
- } catch (Exception e) {
- e.printStackTrace();
- }
- }
- }).start();
- }
- @Override
- public void windowIconified(WindowEvent e) {
- }
- @Override
- public void windowDeiconified(WindowEvent e) {
- }
- @Override
- public void windowDeactivated(WindowEvent e) {
- }
- @Override
- public void windowClosing(WindowEvent e) {
- server.quit();
- System.exit(0);
- }
- @Override
- public void windowClosed(WindowEvent e) {
- }
- @Override
- public void windowActivated(WindowEvent e) {
- }
- });
- }
- /**
- * @param args
- */
- public static void main(String[] args) {
- ServerWindow window = new ServerWindow("文件上传服务端");
- window.setSize(300, 300);
- window.setVisible(true);
- }
- }
- StreamTool.javapackage com.android.socket.utils;
- import java.io.ByteArrayOutputStream;
- import java.io.File;
- import java.io.FileOutputStream;
- import java.io.IOException;
- import java.io.InputStream;
- import java.io.PushbackInputStream;
- public class StreamTool {
- public static void save(File file, byte[] data) throws Exception {
- FileOutputStream outStream = new FileOutputStream(file);
- outStream.write(data);
- outStream.close();
- }
- public static String readLine(PushbackInputStream in) throws IOException {
- char buf[] = new char[128];
- int room = buf.length;
- int offset = 0;
- int c;
- loop: while (true) {
- switch (c = in.read()) {
- case -1:
- case '\n':
- break loop;
- case '\r':
- int c2 = in.read();
- if ((c2 != '\n') && (c2 != -1)) in.unread(c2);
- break loop;
- default:
- if (--room < 0) {
- char[] lineBuffer = buf;
- buf = new char[offset + 128];
- room = buf.length - offset - 1;
- System.arraycopy(lineBuffer, 0, buf, 0, offset);
- }
- buf[offset++] = (char) c;
- break;
- }
- }
- if ((c == -1) && (offset == 0)) return null;
- return String.copyValueOf(buf, 0, offset);
- }
- /**
- * 读取流
- * @param inStream
- * @return 字节数组
- * @throws Exception
- */
- public static byte[] readStream(InputStream inStream) throws Exception{
- ByteArrayOutputStream outSteam = new ByteArrayOutputStream();
- byte[] buffer = new byte[1024];
- int len = -1;
- while( (len=inStream.read(buffer)) != -1){
- outSteam.write(buffer, 0, len);
- }
- outSteam.close();
- inStream.close();
- return outSteam.toByteArray();
- }
- }
运行效果如下:
Android前端控制:
后台监控日志:
下载后的文件路径: