Java基础教程——Socket编程
Socket通常也称作“套接字”，用于描述IP地址和端口，可以用来实现不同虚拟机或不同计算机之间的通信。
——百度百科套接字允许应用程序插入到网络中，并与插入到网络中的其他应用程序通信。
——《TCP/IP Socket编程·TCP/IP in C》
Socket编程示意图：
服务器需要先启动，等待客户端连接。
客户端主动连接服务器，连接成功才能通信。
字节流版本
服务端：
import java.net.*;
import java.io.*;
public class Skt字节流S {
public static void main(String[] args) {
try {
ServerSocket sSocket = new ServerSocket(8888);
System.out.println("new ServerSocket");
Socket s = sSocket.accept();
System.out.println("accept()");
InputStream is = s.getInputStream();
OutputStream os = s.getOutputStream();
byte[] b = new byte[1024];
int len = is.read(b);
String str = new String(b, 0, len);
System.out.println("客户端说：" + str);
os.write("对不起，我们这三碗不过岗".getBytes());
is.close();
os.close();
s.close();
sSocket.close();
System.out.println("服务器端，OVER");
} catch (Exception e) {
}
}
}
客户端：
import java.net.*;
import java.io.*;
public class Skt字节流C {
public static void main(String[] args) {
try {
// Socket s = new Socket(InetAddress.getLocalHost() , 8888);
Socket s = new Socket("127.0.0.1", 8888);
InputStream is = s.getInputStream();
OutputStream os = s.getOutputStream();
os.write("你好，我要10碗酒，三斤牛肉".getBytes());
byte[] b = new byte[1024];
int len = -1;
while ((len = is.read(b)) > 0) {
String str = new String(b, 0, len);
System.out.println("服务器端的回复：" + str);
}
is.close();
os.close();
s.close();
System.out.println("客户端Over");
} catch (UnknownHostException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}
看效果时，可以一个程序用Eclipse启动，一个用cmd启动，编译时如果有错，可用如下语句：
javac -encoding utf-8 XXX.java
cmd运行程序时，不要有包名。
字符流版本
服务端：
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
public class SktCharacterS {
public static void main(String[] args) {
try {
ServerSocket sSocket = new ServerSocket(8888);
Socket s = sSocket.accept();
InputStream is = s.getInputStream();
OutputStream os = s.getOutputStream();
InputStreamReader isr = new InputStreamReader(is);
BufferedReader bufR = new BufferedReader(isr);
PrintWriter prtW = new PrintWriter(os);
// -----------------------------------------------------
String str = bufR.readLine();
System.out.println("——" + str);
prtW.print("你好，我是服务器");
prtW.flush();
bufR.close();
isr.close();
is.close();
prtW.close();
os.close();
s.close();
sSocket.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
客户端：
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.net.InetAddress;
import java.net.Socket;
import java.net.UnknownHostException;
public class SktCharacterC {
public static void main(String[] args) {
Socket s;
try {
s = new Socket(InetAddress.getLocalHost(), 8888);
InputStream is = s.getInputStream();
OutputStream os = s.getOutputStream();
PrintWriter prtW = new PrintWriter(os);
InputStreamReader isr = new InputStreamReader(is);
BufferedReader bufR = new BufferedReader(isr);
// --------------------------------------------------
prtW.println("你好我是客户机");
prtW.flush();
String str = bufR.readLine();
System.out.println("——" + str);
bufR.close();
isr.close();
is.close();
prtW.close();
os.close();
s.close();
} catch (UnknownHostException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}
socket发送文件(基本款)
服务端：
import java.net.*;
import java.io.*;
public class SktFileS {
public static void main(String[] args) {
try {
ServerSocket sSocket = new ServerSocket(8888);
Socket s = sSocket.accept();
InputStream ips = s.getInputStream();
FileOutputStream fos = new FileOutputStream("recv.png");
byte[] b = new byte[1024];
int nLen = -1;
while (true) {
nLen = ips.read(b);
if (nLen == -1) {
break;
}
fos.write(b, 0, nLen);
}
fos.close();
ips.close();
s.close();
sSocket.close();
} catch (Exception e) {
} finally {
System.out.println("服务器端，OVER");
}
}
}
客户端：
import java.net.*;
import java.io.*;
public class SktFileC {
public static void main(String[] args) {
try {
Socket s = new Socket("127.0.0.1", 8888);
OutputStream ops = s.getOutputStream();
FileInputStream fis = new FileInputStream("send.png");
byte[] b = new byte[1024];
int nLength = -1;
while ((nLength = fis.read(b)) > 0) {
ops.write(b, 0, nLength);
}
fis.close();
ops.close();
s.close();
} catch (UnknownHostException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
System.out.println("客户端Over");
}
}
}
socket发送文件(带文件名)
服务端：
import java.net.*;
import java.io.*;
public class SktFileWithNameS {
public static void main(String[] args) {
try {
ServerSocket sSocket = new ServerSocket(8888);
Socket s = sSocket.accept();
InputStream ips = s.getInputStream();
InputStreamReader isr = new InputStreamReader(ips);
BufferedReader br = new BufferedReader(isr);
// 读取文件名
FileOutputStream fos = new FileOutputStream("recv_" + br.readLine());
// 读取文件
byte[] b = new byte[1024];
int nLen = -1;
while (true) {
nLen = ips.read(b);
if (nLen == -1) {
break;
}
fos.write(b, 0, nLen);
}
fos.close();
ips.close();
s.close();
sSocket.close();
} catch (Exception e) {
} finally {
System.out.println("服务器端，OVER");
}
}
}
客户端：
import java.net.*;
import java.io.*;
public class SktFileWithNameC {
public static void main(String[] args) {
try {
Socket s = new Socket("127.0.0.1", 8888);
// 输出流
OutputStream ops = s.getOutputStream();
PrintWriter pw = new PrintWriter(ops, true);
// 文件读入
String strFile = "send.png";
File f = new File(strFile);
FileInputStream fis = new FileInputStream(f);
// 写文件名
pw.println(f.getName());
// 文件内容发送
byte[] b = new byte[1024];
int nLength = -1;
while ((nLength = fis.read(b)) > 0) {
ops.write(b, 0, nLength);
}
pw.close();
fis.close();
ops.close();
s.close();
} catch (UnknownHostException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
System.out.println("客户端Over");
}
}
}
