java学习笔记——网络编程
网络通信要素
基于tcp协议的网络编程
需要注意的是:
Socket.shutdownInput( )与Socket.shutdownOutput( )方法,如果不使用这两个方法很可能就会造成read阻塞(客户端与服务端都read时)
/*
* 从客户端发送文件给服务端,服务端保存到本地。并返回“发送成功”给客户端。并关闭相应的连接。
*/
public class TestTCP3 {
//客户端
@Test
public void client() throws IOException{
Socket s = new Socket(InetAddress.getByName("127.0.0.1"), 9898);
FileInputStream fis = new FileInputStream("./1.jpg");
OutputStream os = s.getOutputStream();
byte[] b = new byte[1024];
int len = 0;
while((len = fis.read(b)) != -1){
os.write(b, 0, len);
}
s.shutdownOutput();
//客户端接收反馈
InputStream in = s.getInputStream();
while((len = in.read(b)) != -1){
System.out.println(new String(b, 0, len));
}
in.close();
os.close();
fis.close();
s.close();
}
//服务端
@Test
public void server() throws IOException{
ServerSocket ss = new ServerSocket(9898);
Socket s = ss.accept();
InputStream in = s.getInputStream();
FileOutputStream fos = new FileOutputStream("2.jpg");
byte[] b = new byte[1024];
int len = 0;
while((len = in.read(b)) != -1){
fos.write(b, 0, len);
}
s.shutdownInput();
OutputStream os = s.getOutputStream();
os.write("接收美图成功!".getBytes());
os.close();
fos.close();
in.close();
s.close();
ss.close();
}
}
基于udp协议的网络编程
public class TestUDP {
//发送端
@Test
public void send() throws IOException{
DatagramSocket ds = new DatagramSocket();
int i = 0;
while(i <= 100){
String str = "使用 UDP 协议发送数据给接收端! --- " + i++;
byte[] buf = str.getBytes();
DatagramPacket dp = new DatagramPacket(buf, 0, buf.length, InetAddress.getByName("127.0.0.1"), 9898);
try {
Thread.sleep(20);
} catch (InterruptedException e) {
}
ds.send(dp);
}
ds.close();
}
//接收端
@Test
public void receive() throws IOException{
DatagramSocket ds = new DatagramSocket(9898);
byte[] buf = new byte[1024];
int i = 0;
while(i <= 100){
DatagramPacket dp = new DatagramPacket(buf, buf.length);
ds.receive(dp);
System.out.println(new String(dp.getData(), 0, dp.getLength()));
i++;
}
ds.close();
}
}
URL编程
public class TestURL {
public static void main(String[] args) throws IOException {
URL url = new URL("http://down.sandai.net/XLNetAcc/XLNetAccSetup.exe");
/*
public String getProtocol( ) 获取该URL的协议名
public String getHost( ) 获取该URL的主机名
public String getPort( ) 获取该URL的端口号
public String getPath( ) 获取该URL的文件路径
public String getFile( ) 获取该URL的文件名
public String getRef( ) 获取该URL在文件中的相对位置
public String getQuery( ) 获取该URL的查询名
*/
/*System.out.println(url.getProtocol());
System.out.println(url.getHost());
System.out.println(url.getPort());
System.out.println(url.getPath());
System.out.println(url.getFile());
System.out.println(url.getRef());
System.out.println(url.getQuery());*/
/*InputStream in = url.openStream();
byte[] b = new byte[1024];
int len = 0;
while((len = in.read(b)) != -1){
System.out.println(new String(b, 0, len));
}
in.close();*/
URLConnection uc = url.openConnection();
// OutputStream os = uc.getOutputStream();
/*InputStream in = uc.getInputStream();
byte[] b = new byte[1024];
int len = 0;
while((len = in.read(b)) != -1){
System.out.println(new String(b, 0, len));
}
in.close();*/
InputStream in = uc.getInputStream();
FileOutputStream fos = new FileOutputStream("d:/xunlei.exe");
byte[] b = new byte[1024];
int len = 0;
while((len = in.read(b)) != -1){
fos.write(b, 0, len);
}
fos.close();
in.close();
}
}