1. InetAddress类2. Socket： IP地址和端口号的结合，socket允许程序把网络连接当成一个流，数据在两个socket间通过IO传输， 通信的两端都要有socket. 主动发起通信请求的是客户端，等待通信请求的是服务端3. DatagramSocket 和 DatagramPacket实现了UDP协议网络程序， 使用DatagramSocket发送和接收，系统不保证UDP数据报一定能够安全送到目的地，也不能确定什么时候可以抵达 DatagramPacket对象封装了UDP数据报，在数据报中包含了发送端的IP地址和端口号以及接收端的IP地址和端口号，给出了完整的地址信息，因此无须建立发送方和接收方的连接4. URL类 URL u = new URL("http://www.baidu.com"); InputStream in = u.openStream();
URLConnection uc = u.openConnection(); uc.getInputStream(); uc.getOutputSteam();
1 package learn.JavaBasics.Class;
2
3 import java.io.*;
4 import java.net.InetAddress;
5 import java.net.ServerSocket;
6 import java.net.Socket;
7 import java.net.UnknownHostException;
8
9 public class SocketDemo {
10 public void server() {
11 ServerSocket ss = null;
12 Socket s = null;
13 InputStream in = null;
14 OutputStream out = null;
15
16 try {
17 //开始在端口监听
18 ss = new ServerSocket(9999);
19
20 //当有连接进来时，会新建一个socket
21 s = ss.accept();
22
23 //获取输入流
24 in = s.getInputStream();
25
26 //对输入流进行处理
27 byte[] b = new byte[1024];
28 int len;
29 String msg = "";
30
31 while((len=in.read(b)) != -1) {
32 msg = new String(b, 0, len);
33 }
34
35 System.out.println("The message from "+ s.getInetAddress().getHostName()+
36 "(ip:"+ s.getInetAddress().getHostAddress()+") is: \""+msg+"\"");
37
38
39 //获取输出流，反馈信息
40 out = s.getOutputStream();
41 out.write("The msg from client has been received".getBytes());
42 } catch (IOException e) {
43 // TODO Auto-generated catch block
44 e.printStackTrace();
45 } finally {
46 if (in != null) {
47 try {
48 in.close();
49 } catch (IOException e) {
50 // TODO Auto-generated catch block
51 e.printStackTrace();
52 }
53 }
54
55 if (s != null) {
56 try {
57 s.close();
58 } catch (IOException e) {
59 // TODO Auto-generated catch block
60 e.printStackTrace();
61 }
62 }
63
64 if (ss != null) {
65 try {
66 ss.close();
67 } catch (IOException e) {
68 // TODO Auto-generated catch block
69 e.printStackTrace();
70 }
71 }
72
73 if (out != null) {
74 try {
75 out.close();
76 } catch (IOException e) {
77 // TODO Auto-generated catch block
78 e.printStackTrace();
79 }
80 }
81 }
82 }
83
84 public void client() {
85 Socket s = null;
86 OutputStream out = null;
87 InputStream in = null;
88
89 try {
90 //新建一个Socket
91 s = new Socket(InetAddress.getLocalHost(), 9999);
92
93 //获取输出流
94 out = s.getOutputStream();
95
96 //发送信息， 并提示
97 out.write("This is client".getBytes());
98 System.out.println("client message has sent");
99
100 //这句话存在的原因是，Server端的getInputSream流的read方法是阻塞， 它在接收信息，但不知道信息是否接收完全，所以一直在等待，
101 //所以Server端的反馈信息无发发送过来，程序死掉，
102 //这里显式的通知Server，发送结束
103 //FileInputSteam里的read方法与这个一样，但BufferInputSteam里的read方法是非阻塞的
104 s.shutdownOutput();
105
106 //获取输入流，接收服务端的反馈信息
107 in = s.getInputStream();
108
109 byte[] b = new byte[1024];
110 int len;
111 String msg = "";
112
113 while((len=in.read(b)) != -1) {
114 msg = new String(b, 0, len);
115 }
116 System.out.println("Response from Server: "+msg);
117 System.out.println("connection over");
118
119 //这里的后边没有了，所以服务端可以不显式的提示，不影响功能
120 } catch (IOException e) {
121 // TODO Auto-generated catch block
122 e.printStackTrace();
123 } finally {
124 if (out != null) {
125 try {
126 out.close();
127 } catch (IOException e) {
128 // TODO Auto-generated catch block
129 e.printStackTrace();
130 }
131 }
132 if (s != null) {
133 try {
134 s.close();
135 } catch (IOException e) {
136 // TODO Auto-generated catch block
137 e.printStackTrace();
138 }
139 }
140
141 if (in != null) {
142 try {
143 in.close();
144 } catch (IOException e) {
145 // TODO Auto-generated catch block
146 e.printStackTrace();
147 }
148 }
149 }
150 }
151
152 public static void main(String[] args) {
153 new Thread(new Runnable(){
154 @Override
155 public void run() {
156 // TODO Auto-generated method stub
157 new SocketDemo().server();
158 }
159 }).start();
160
161 new Thread(new Runnable() {
162 @Override
163 public void run() {
164 // TODO Auto-generated method stub
165 new SocketDemo().client();
166 }
167 }).start();
168 }
169
170 }
1 package learn.JavaBasics.Class;
2
3 import java.io.IOException;
4 import java.net.DatagramPacket;
5 import java.net.DatagramSocket;
6 import java.net.InetAddress;
7 import java.net.SocketException;
8 import java.net.UnknownHostException;
9
10 public class TestUDP {
11 public void receive(){
12 DatagramSocket ds = null;
13
14 try {
15 //定义接收的数据报大小
16 byte[] b = new byte[1024];
17 DatagramPacket packet = new DatagramPacket(b, 0, b.length);
18
19 //定义一个接收的Socket，用于在特定的端口接收指定大小的数据报
20 ds = new DatagramSocket(9999);
21 ds.receive(packet);
22
23 String str = new String(packet.getData(), 0, packet.getLength());
24
25 System.out.println(str);
26 } catch (SocketException e) {
27 // TODO Auto-generated catch block
28 e.printStackTrace();
29 } catch (IOException e) {
30 // TODO Auto-generated catch block
31 e.printStackTrace();
32 } finally {
33 if (ds != null) {
34 ds.close();
35 }
36 }
37 }
38
39 public void send() {
40 DatagramSocket ds = null;
41
42 try {
43 //新建一个用于发送的Socket
44 ds = new DatagramSocket();
45
46 //数据
47 byte[] b = "你好， 这里是发送端的数据, UDP sender".getBytes();
48
49 //封装数据到数据报中， 一个数据报不能大于64K, 记录着数据信息， 两端的IP和端口号
50 DatagramPacket packet = new DatagramPacket(b, 0, b.length, InetAddress.getLocalHost(), 9999);
51
52 //使用Socket把数据报发走
53 ds.send(packet);
54 } catch (SocketException e) {
55 // TODO Auto-generated catch block
56 e.printStackTrace();
57 } catch (UnknownHostException e) {
58 // TODO Auto-generated catch block
59 e.printStackTrace();
60 } catch (IOException e) {
61 // TODO Auto-generated catch block
62 e.printStackTrace();
63 } finally {
64 if (ds != null) {
65 ds.close();
66 }
67 }
68 }
69
70 public static void main(String[] args) {
71 new Thread(new Runnable(){
72 @Override
73 public void run() {
74 new TestUDP().receive();
75 }
76 }).start();
77
78 new Thread(new Runnable(){
79 @Override
80 public void run() {
81 new TestUDP().send();
82 }
83 }).start();
84 }
85 }
时间： 2024-10-05 06:49:57