MySQL -- 修改root密碼
阿新 • • 發佈：2020-07-25
網路程式設計
IP地址
ip地址：inetAddress
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唯一定位一臺網路上的計算機
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127.0.0.1：本機 localhost
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ip地址的分類
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ipv4 四個位元組組成 0-255
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ipv6 128位 。八個無符號整數！
2001:1ab2:cccc:0000:0015:1e2d:1314:22bb -
公網（網際網路） 私網（區域網）
- ABCD類地址
- 192.168..xx.xx 專門給組織內部使用
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public class Ip { public static void main(String[] args) { try { //查詢本機地址 InetAddress inetAddress1 = InetAddress.getByName("127.0.0.1"); System.out.println(inetAddress1); InetAddress inetAddress3 = InetAddress.getByName("localhost"); System.out.println(inetAddress3); InetAddress localHost = InetAddress.getLocalHost(); System.out.println(localHost); //百度ip地址 InetAddress inetAddress2 = InetAddress.getByName("www.baidu.com"); System.out.println(inetAddress2); } catch (UnknownHostException e) { e.printStackTrace(); } } }
埠
埠表示計算機上的一個程式的程序
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不同的程序又不同的埠號！用來區分軟體
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被規定0-65535
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TCP / UDP ：65535 * 2 TCP:80 UDP:80 單個協議下埠號不能衝突，不同協議埠號可以相同
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埠號分類
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公有埠0-1023
- HTTP:80
- HTTPS:443
- FTP:21
- Telent:23
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程式註冊埠：1024-49151 分配和使用者和程式
- Tomcat：8080
- MySQL:3306
- Oracle：1521
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動態埠、私有埠：49152-65535
netstat -ano #檢視所有的埠 netstat -ano|findstr "" #檢視指定的埠 tasklist|findstr "" #檢視指定埠的程序
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通訊協議
協議：約定，就好比我現在說的普通話才能交流
網路通訊協議：速率、傳輸位元速率、程式碼結構、傳輸控制
問題：非常的複雜？
大事化小：分層！
TCP/IP協議簇:實際上時一組協議
- 重要：
- TCP：使用者傳輸協議
- UDP：使用者資料報協議
- 出名的協議：
- TCP
- IP:網路互聯協議
TCP UDP對比
TCP:打電話
- 連線、穩定
- 三次握手 四次揮手
- A你愁啥？B瞅你咋地？A幹一場！ 最少需要三次才能保證穩定連線
- A我要走了 B你真的要走了麼？ B你真的真的要走了麼？ A我真的要走了
- 客戶端、服務端
- 傳輸完成，釋放連線、效率低
UDP:發簡訊
- 不連線、不穩定
- 客戶端、服務端：沒有明確的界限
- 不管有沒有準備好，都可以傳送
- 導彈
- DDOS：洪水攻擊！飽和攻擊
TCP實現聊天
客戶端
- 連線伺服器 Socket
- 傳送訊息
//客戶端
public class TcpClientDemo {
public static void main(String[] args) {
Socket socket = null;
OutputStream outputStream = null;
try {
//1.知道伺服器的地址
InetAddress serverIp = InetAddress.getByName("127.0.0.1");
int port = 9999;
//2.建立一個socket連線
socket = new Socket(serverIp,port);
//3.傳送訊息 IO流
outputStream = socket.getOutputStream();
outputStream.write("nihao".getBytes());
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
if (outputStream != null)
outputStream.close();
} catch (IOException e) {
e.printStackTrace();
}
try {
if(socket != null)
socket.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
伺服器
- 建立服務埠 ServerSocket
- 等待使用者的連線 通過accept
- 接受使用者的訊息
//服務端
public class TcpServerDemo {
public static void main(String[] args) {
ServerSocket serverSocket = null;
Socket accept = null;
InputStream inputStream = null;
ByteArrayOutputStream byteArrayOutputStream = null;
try {
//1.有一個地址
serverSocket = new ServerSocket(9999);
//2.等待客戶端連線進來
accept = serverSocket.accept();
//3.讀取客戶端的訊息
inputStream = accept.getInputStream();
//管道流
byteArrayOutputStream = new ByteArrayOutputStream();
byte[] buffer = new byte[1024];
int len;
while ((len=inputStream.read(buffer)) != -1){
byteArrayOutputStream.write(buffer,0,len);
}
System.out.println(byteArrayOutputStream.toString());
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
if (byteArrayOutputStream != null)
byteArrayOutputStream.close();
} catch (IOException e) {
e.printStackTrace();
}
try {
if(inputStream != null)
inputStream.close();
} catch (IOException e) {
e.printStackTrace();
}
try {
if(accept != null)
accept.close();
} catch (IOException e) {
e.printStackTrace();
}
try {
if (serverSocket != null)
serverSocket.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
TCP檔案上傳實現
伺服器端
public class TCPServer{
public static void main(String[] args){
ServerSocket serverSocket = null;
Socket accept = null;//阻塞式監聽，會一直等待客戶端連線
InputStream inputStream = null;
FileOutputStream fileOutputStream = null;
try {
//建立服務
serverSocket = new ServerSocket(9090);
//監聽客戶端的連線
accept = serverSocket.accept();
//獲取輸入流
inputStream = accept.getInputStream();
//檔案輸出
fileOutputStream = new FileOutputStream(new File("基礎語法\\receive.jpg"));
byte[] buffer = new byte[1024];
int len;
while ((len = inputStream.read(buffer)) != -1){
fileOutputStream.write(buffer,0,len);
}
//通知客戶端我接受完畢了
OutputStream outputStream = accept.getOutputStream();
outputStream.write("我接受完畢了，可以斷開了".getBytes());
} catch (IOException e) {
e.printStackTrace();
} finally {
//關閉資源
try {
if (fileOutputStream != null)
fileOutputStream.close();
} catch (IOException e) {
e.printStackTrace();
}
try {
if (inputStream != null)
inputStream.close();
} catch (IOException e) {
e.printStackTrace();
}
try {
if (accept != null)
accept.close();
} catch (IOException e) {
e.printStackTrace();
}
try {
if (serverSocket != null)
serverSocket.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
客戶端
public class TcpClient{
public static void main(String[] args) {
Socket socket = null;
OutputStream outputStream = null;
FileInputStream fileInputStream = null;
InputStream inputStream = null;
ByteArrayOutputStream byteArrayOutputStream = null;
try {
//建立Socket連線
socket = new Socket(InetAddress.getByName("127.0.0.1"),9090);
//建立一個輸出流
outputStream = socket.getOutputStream();
//檔案流
//讀取檔案
fileInputStream = new FileInputStream(new File("基礎語法\\沙灘.jpg"));
//寫出檔案
byte[] buffer = new byte[1024];
int len;
while ((len = fileInputStream.read(buffer)) != -1){
outputStream.write(buffer,0,len);
}
//通知伺服器，我已經結束了
socket.shutdownOutput();//我已經傳輸完了!
//確定伺服器接受完畢，才能斷開連線
inputStream = socket.getInputStream();
byteArrayOutputStream = new ByteArrayOutputStream();
byte[] buffer2= new byte[1024];
int len2;
while ((len2 = inputStream.read(buffer2)) != -1){
byteArrayOutputStream.write(buffer2,0,len2);
}
System.out.println(byteArrayOutputStream.toString());
} catch (IOException e) {
e.printStackTrace();
} finally {
//關閉資源
try {
if (byteArrayOutputStream!=null)
byteArrayOutputStream.close();
} catch (IOException e) {
e.printStackTrace();
}
try {
if (inputStream!=null)
inputStream.close();
} catch (IOException e) {
e.printStackTrace();
}
try {
if (fileInputStream!=null)
fileInputStream.close();
} catch (IOException e) {
e.printStackTrace();
}
try {
if (outputStream!=null)
outputStream.close();
} catch (IOException e) {
e.printStackTrace();
}
try {
if (socket!=null)
socket.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
Tomcat
服務端
- 自定義 S
- Tomcat伺服器 S java後臺開發！
客戶端
- 自定義 C
- 瀏覽器 B
UDP
發簡訊：不用連結 需要知道對方的地址
傳送訊息
-
傳送端
//不需要連線伺服器 public class Demo { public static void main(String[] args) throws Exception { //建立一個Socket DatagramSocket datagramSocket = new DatagramSocket(); //建個包 String msg = "nihao"; //傳送給誰 InetAddress localhost = InetAddress.getByName("localhost"); int port = 9999; //資料 資料的長度起始 傳送給誰 DatagramPacket datagramPacket = new DatagramPacket(msg.getBytes(),0,msg.getBytes().length,localhost,port); //傳送包 datagramSocket.send(datagramPacket); } } -
接收端
等待客戶端的連線 public class Demo01 { public static void main(String[] args) throws Exception { //開放埠 DatagramSocket datagramSocket = new DatagramSocket(9999); //接收資料 接受包 byte[] buffer = new byte[1024]; DatagramPacket datagramPacket = new DatagramPacket(buffer, 0, buffer.length); //阻塞接收 datagramSocket.receive(datagramPacket); System.out.println(datagramPacket.getAddress().getHostAddress()); System.out.println(new String(datagramPacket.getData(),0,datagramPacket.getLength())); //關閉連線 datagramSocket.close(); }迴圈傳送訊息
public class Sender01 { public static void main(String[] args) throws Exception { DatagramSocket socket = new DatagramSocket(8888); //準備資料 控制檯讀取 System.in BufferedReader reader = new BufferedReader(new InputStreamReader(System.in)); while (true){ String data = reader.readLine(); byte[] datas = data.getBytes(); DatagramPacket packet = new DatagramPacket(datas, 0, datas.length, new InetSocketAddress("localhost", 6666)); socket.send(packet); if (data.equals("bye")){ break; } } socket.close(); } }迴圈接收訊息
public class Receicer01 { public static void main(String[] args) throws Exception { DatagramSocket socket = new DatagramSocket(6666); while (true){ //準備接受包裹 byte[] contain= new byte[1024]; DatagramPacket packet = new DatagramPacket(contain,0,contain.length); socket.receive(packet);//阻塞式接受包裹 //斷開連線 bye byte[] data = packet.getData(); String datas = new String(data,0,data.length); System.out.println(datas); if (datas.equals("bye")){ break; } } socket.close(); } }線上諮詢：兩個人都可以是傳送方，也都可以時接收方 多執行緒實現
傳送執行緒
public class TalkSend implements Runnable { DatagramSocket socket = null; BufferedReader reader = null; private int fromPort; private String toIp; private int toPort; public TalkSend(int fromPort, String toIp, int toPort) { this.fromPort = fromPort; this.toIp = toIp; this.toPort = toPort; try { socket = new DatagramSocket(fromPort); reader = new BufferedReader(new InputStreamReader(System.in)); } catch (SocketException e) { e.printStackTrace(); } } @Override public void run() { while (true){ try { String data = reader.readLine(); byte[] datas = data.getBytes(); DatagramPacket packet = new DatagramPacket(datas, 0, datas.length, new InetSocketAddress(this.toIp, this.toPort)); socket.send(packet); if (data.equals("bye")){ break; } } catch (IOException e) { e.printStackTrace(); } } socket.close(); } }接收執行緒
public class TalkReceive implements Runnable { DatagramSocket socket = null; private int port; private String msgFrom; public TalkReceive(int port,String msgFrom) { this.port = port; this.msgFrom = msgFrom; try { socket = new DatagramSocket(port); } catch (SocketException e) { e.printStackTrace(); } } @Override public void run() { while (true){ try { //準備接受包裹 byte[] contain= new byte[1024]; DatagramPacket packet = new DatagramPacket(contain,0,contain.length); socket.receive(packet);//阻塞式接受包裹 //斷開連線 bye byte[] data = packet.getData(); String datas = new String(data,0,data.length); System.out.println(msgFrom+":"+datas); if (datas.equals("bye")){ break; } } catch (IOException e) { e.printStackTrace(); } } socket.close(); } }學生端
public class TalkStudent { public static void main(String[] args) { //開啟兩個執行緒 new Thread(new TalkSend(7777,"localhost",9999)).start(); new Thread(new TalkReceive(8888,"老師")).start(); } }老師端
public class TalkTeacher { public static void main(String[] args) { //開啟兩個執行緒 new Thread(new TalkSend(5555,"localhost",8888)).start(); new Thread(new TalkReceive(9999,"學生")).start(); } }URL
統一資源定位符:定位網際網路上的某一個資源
協議://ip地址:埠/專案名/資源public class Url { public static void main(String[] args) throws MalformedURLException { URL url = new URL("http://localhost:8080/helloworld/index.jsp?username=qiu&password=123"); System.out.println(url.getProtocol()); //協議 System.out.println(url.getHost()); //主機 ip System.out.println(url.getPort()); //埠 System.out.println(url.getPath()); //檔案 System.out.println(url.getFile()); //全路徑 System.out.println(url.getQuery()); //引數 } }下載網路資源
public class Url { public static void main(String[] args) throws Exception { //下載地址 URL url = new URL("http://localhost:8080/helloworld/index.jsp?username=qiu&password=123"); //連線到這個資源 HTTP HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection(); InputStream inputStream = urlConnection.getInputStream(); FileOutputStream fileOutputStream = new FileOutputStream("基礎語法\\abc.txt"); byte[] buffer = new byte[1024]; int len; while ((len = inputStream.read(buffer)) != -1){ fileOutputStream.write(buffer,0,len); } fileOutputStream.close(); inputStream.close(); urlConnection.disconnect(); } }