diff --git a/code/src/main/java/com/raorao/interview/toutiao/T.java b/code/src/main/java/com/raorao/interview/toutiao/T.java new file mode 100644 index 00000000..b4163d6e --- /dev/null +++ b/code/src/main/java/com/raorao/interview/toutiao/T.java @@ -0,0 +1,11 @@ +package com.raorao.interview.toutiao; + +/** + * . + * + * @author Xiong Raorao + * @since 2018-08-25-10:02 + */ +public class T { + +} diff --git a/code/src/main/java/com/raorao/interview/toutiao/t1/Main.java b/code/src/main/java/com/raorao/interview/toutiao/t1/Main.java new file mode 100644 index 00000000..b8e9e9b9 --- /dev/null +++ b/code/src/main/java/com/raorao/interview/toutiao/t1/Main.java @@ -0,0 +1,25 @@ +package com.raorao.interview.toutiao.t1; + +/** + * . + * + * @author Xiong Raorao + * @since 2018-08-25-10:02 + */ +public class Main { + + public static void main(String[] args) { + + } + + private static void process(boolean[][] arr) { + int num = 1; + int m = arr.length; + int n = arr[0].length; + for (int i = 0; i < m; i++) { + for (int j = 0; j < n; j++) { + + } + } + } +} diff --git a/code/src/main/java/com/raorao/interview/toutiao/t2/Main.java b/code/src/main/java/com/raorao/interview/toutiao/t2/Main.java new file mode 100644 index 00000000..96b89380 --- /dev/null +++ b/code/src/main/java/com/raorao/interview/toutiao/t2/Main.java @@ -0,0 +1,88 @@ +package com.raorao.interview.toutiao.t2; + +import java.util.ArrayList; +import java.util.List; +import java.util.Scanner; + +/** + * 字符串. + * + * @author Xiong Raorao + * @since 2018-08-25-10:31 + */ +public class Main { + + public static void main(String[] args) { + Scanner scanner = new Scanner(System.in); + int t = Integer.parseInt(scanner.nextLine()); + List ret = new ArrayList<>(); + List> inputs = new ArrayList<>(); + for (int i = 0; i < t; i++) { + int n = Integer.parseInt(scanner.nextLine()); + List temp = new ArrayList<>(); + while (n-- > 0) { + temp.add(scanner.nextLine()); + } + inputs.add(temp); + } + for (List list : inputs) { + ret.add(process(list)); + } + for (String s : ret) { + System.out.println(s); + } + + } + + private static String process(List strings) { + List ret = new ArrayList<>(); + for (int i = 0; i < strings.size(); i++) { + for (int j = i + 1; j < strings.size(); j++) { + ret.add(process(strings.get(i), strings.get(j))); + } + } + for (String s:ret){ + if (s.equals("Yeah")){ + return "Yeah"; + } + } + return "Sad"; + } + + private static String process(String s1, String s2) { + char start = s2.charAt(0); + List starts = find(s1, start); + for (String s : starts) { + if (s.equals(s2)) { + return "Yeah"; + } + } + return "Sad"; + } + + private static List find(String s1, char start) { + List ret = new ArrayList<>(); + for (int i = 0; i < s1.length(); i++) { + if (start == s1.charAt(i)) { + String tmp1 = s1.substring(i + 1, s1.length()); + String tmp; + if (i == 0) { + tmp = tmp1; + } else { + tmp = tmp1 + s1.substring(0, i); + } + ret.add(start + tmp); + ret.add(start + invert(tmp)); + } + } + return ret; + } + + private static String invert(String s) { + StringBuilder sb = new StringBuilder(); + for (int i = s.length() - 1; i >= 0; i--) { + sb.append(s.charAt(i)); + } + return sb.toString(); + } +} diff --git a/code/src/main/java/com/raorao/interview/toutiao/t5/Main.java b/code/src/main/java/com/raorao/interview/toutiao/t5/Main.java new file mode 100644 index 00000000..1959793e --- /dev/null +++ b/code/src/main/java/com/raorao/interview/toutiao/t5/Main.java @@ -0,0 +1,67 @@ +package com.raorao.interview.toutiao.t5; + +import java.util.Scanner; + +/** + * . + * + * @author Xiong Raorao + * @since 2018-08-25-11:30 + */ +public class Main { + + private static final String ERR = "cannot_answer"; + + public static void main(String[] args) { + Scanner scanner = new Scanner(System.in); + String[] line1 = scanner.nextLine().split(" "); + int n = Integer.parseInt(line1[0]); + int m = Integer.parseInt(line1[1]); + char[] y = new char[n]; + int[] k = new int[n]; + char[] x = new char[n]; + char[][] q = new char[m][2]; + for (int i = 0; i < n; i++) { + String line = scanner.nextLine(); + String[] eq = line.split(" = "); + y[i] = eq[0].charAt(0); + String[] eq2 = eq[1].split(" - "); + k[i] = Integer.parseInt(eq2[0]); + x[i] = eq2[1].charAt(0); + } + for (int i = 0; i < m; i++) { + String line = scanner.nextLine(); + String[] eq = line.split(" - "); + q[i][0] = eq[0].charAt(0); + q[i][1] = eq[1].charAt(0); + } + + String[] ret = new String[2]; + for (int i = 0; i < m; i++) { + ret[i] = process(y, k, x, q[i]); + } + for (String s : ret) { + System.out.println(s); + } + } + + private static String process(char[] y, int[] k, char[] x, char[] q) { + int index1 = getIndex(y, q[0]); + int index2 = getIndex(x, q[1]); + if (index1 != -1 && index2 != -1 && index1 != index2) { + int res = k[index1] - k[index2]; + return String.valueOf(res); + } + return ERR; + } + + private static int getIndex(char[] chars, int q) { + for (int i = 0; i < chars.length; i++) { + if (q == chars[i]) { + return i; + } + } + return -1; + } + +} diff --git a/code/src/main/java/com/raorao/java/socket/TCPClient.java b/code/src/main/java/com/raorao/java/socket/TCPClient.java new file mode 100644 index 00000000..6c49d9b4 --- /dev/null +++ b/code/src/main/java/com/raorao/java/socket/TCPClient.java @@ -0,0 +1,45 @@ +package com.raorao.java.socket; + +import java.io.BufferedReader; +import java.io.DataOutputStream; +import java.io.InputStreamReader; +import java.net.Socket; + +/** + * . + * + * @author Xiong Raorao + * @since 2018-08-27-22:40 + */ +public class TCPClient { + + public static void main(String[] args) throws Exception { + //创建两个String类型的字符串用来发送和接受 + String sentence; + String modifiedSentence; + + //创建输入流，用来接受键盘输入 + BufferedReader inFromUser = new BufferedReader(new InputStreamReader(System.in)); + + //创建一个Socket类型的 clientSocket 用来发起服务器和客户机之间的连接 + Socket clientSocket = new Socket("127.0.0.1", 6789); + + //创建向服务器发送信息的输出流 + DataOutputStream outToServer = new DataOutputStream(clientSocket.getOutputStream()); + + //创建输入流，用来接收来自服务器的字节流 + BufferedReader inFormServer = new BufferedReader( + new InputStreamReader(clientSocket.getInputStream())); + + //读流数据 + sentence = inFromUser.readLine(); + + //向服务器发送sentence的字节数据 + outToServer.writeBytes(sentence + '\n'); + + //获取字节流数据为String + modifiedSentence = inFormServer.readLine(); + + System.out.println("Form Server :" + modifiedSentence); + } +} diff --git a/code/src/main/java/com/raorao/java/socket/TCPServer.java b/code/src/main/java/com/raorao/java/socket/TCPServer.java new file mode 100644 index 00000000..fa782ff2 --- /dev/null +++ b/code/src/main/java/com/raorao/java/socket/TCPServer.java @@ -0,0 +1,46 @@ +package com.raorao.java.socket; + +import java.io.BufferedReader; +import java.io.DataOutputStream; +import java.io.InputStreamReader; +import java.net.ServerSocket; +import java.net.Socket; +import java.nio.channels.Channel; + +/** + * . + * + * @author Xiong Raorao + * @since 2018-08-27-22:39 + */ +public class TCPServer { + + public static void main(String[] args) throws Exception { + String clientSentence; + String capitalizedSentence; + + //服务器Socket用来建立连接 + ServerSocket welcomeSocket = new ServerSocket(6789); + + while (true) { + + //用这个连接来获取和发送，自客户端发的数据流 + Socket connectionSocket = welcomeSocket.accept(); + + //获取来自客户端的字节流 + BufferedReader inFromClient = new BufferedReader( + new InputStreamReader(connectionSocket.getInputStream())); + + //发送更改后的数据流 + DataOutputStream outToClient = new DataOutputStream(connectionSocket.getOutputStream()); + + //读取字节成String字符串 + clientSentence = inFromClient.readLine(); + + capitalizedSentence = clientSentence.toUpperCase() + '\n'; + + outToClient.writeBytes(capitalizedSentence); + } + } + +} diff --git a/code/src/main/java/com/raorao/java/socket/UDPClient.java b/code/src/main/java/com/raorao/java/socket/UDPClient.java new file mode 100644 index 00000000..a42473ed --- /dev/null +++ b/code/src/main/java/com/raorao/java/socket/UDPClient.java @@ -0,0 +1,60 @@ +package com.raorao.java.socket; + +import java.io.BufferedReader; +import java.io.InputStreamReader; +import java.net.DatagramPacket; +import java.net.DatagramSocket; +import java.net.InetAddress; + +/** + * . + * + * @author Xiong Raorao + * @since 2018-08-27-22:29 + */ +public class UDPClient { + + public static void main(String[] args) throws Exception { + //读取键盘输入的字节流 + BufferedReader inFromUser = new BufferedReader(new InputStreamReader(System.in)); + + //为客户机创建了一个传输信息的门，但是并没与向TCP那样建立连接 + DatagramSocket clientSocket = new DatagramSocket(); + + //这行代码调用了DNS查询，查询主机名对应的IP地址，后面要用这个地址来向服务器发送信息 + InetAddress IPAddress = InetAddress.getByName("localhost"); + + //需要发送的字节数组 + byte[] sendData; + + //接受的字节数组 + byte[] receiveData = new byte[1024]; + + String sentence = inFromUser.readLine(); + + //将字符串转为字节放入sendData + sendData = sentence.getBytes(); + + //UDP数据报分组，里面包含想要发送的内容以及目的地址等信息 + DatagramPacket sendPacket = new DatagramPacket(sendData, sendData.length, IPAddress, 9876); + + //用这个‘门’来发送这个数据包 + clientSocket.send(sendPacket); + + //获取数据报分组 + DatagramPacket receivePacket = new DatagramPacket(receiveData, receiveData.length); + + //用‘门’获取数据报 + clientSocket.receive(receivePacket); + + //将获取的数据报转为String类型数据 + String modifiedSentence = new String(receivePacket.getData()); + + System.out.println("From Server:" + modifiedSentence); + + //关闭这个门 + clientSocket.close(); + + } + +} diff --git a/code/src/main/java/com/raorao/java/socket/UDPServer.java b/code/src/main/java/com/raorao/java/socket/UDPServer.java new file mode 100644 index 00000000..3078ba58 --- /dev/null +++ b/code/src/main/java/com/raorao/java/socket/UDPServer.java @@ -0,0 +1,46 @@ +package com.raorao.java.socket; + +import java.io.IOException; +import java.net.DatagramPacket; +import java.net.DatagramSocket; +import java.net.InetAddress; + +/** + * . + * + * @author Xiong Raorao + * @since 2018-08-27-22:19 + */ +public class UDPServer { + + public static void main(String[] args) throws IOException { + DatagramSocket serverSocket = new DatagramSocket(9876); + byte[] receiveData = new byte[1024]; + + byte[] sendData; + + while(true){ + + DatagramPacket receivePacket = new DatagramPacket(receiveData,receiveData.length); + + serverSocket.receive(receivePacket); + + String sentence = new String(receivePacket.getData()); + + InetAddress IPAddress = receivePacket.getAddress(); + + int port = receivePacket.getPort(); + + String capitalized = sentence.toUpperCase(); + + sendData = capitalized.getBytes(); + + DatagramPacket sendPacket = new DatagramPacket(sendData,sendData.length,IPAddress,port); + + serverSocket.send(sendPacket); + System.out.println("Recived: " + sentence + "from " + IPAddress + ":" + port); + System.out.println("Send back:" + capitalized); + } + + } +} diff --git a/code/src/main/java/com/raorao/java/test/A.java b/code/src/main/java/com/raorao/java/test/A.java deleted file mode 100644 index 5c857e1d..00000000 --- a/code/src/main/java/com/raorao/java/test/A.java +++ /dev/null @@ -1,11 +0,0 @@ -package com.raorao.java.test; - -/** - * . - * - * @author Xiong Raorao - * @since 2018-08-10-23:27 - */ -public class A { - -} diff --git a/interview/answer.md b/interview/answer.md index 36ad78d2..da5e5feb 100644 --- a/interview/answer.md +++ b/interview/answer.md @@ -237,9 +237,16 @@ Cache就是加快读取的速度，分为磁盘缓存和CPU缓存。 ## UDP为什么不可靠 -UDP只有一个socket接受缓冲区，没有socket发送缓冲区，即只要有数据就发，不管对方是否可以正确接受。而在对方的socket接受缓冲区满了之后，新来的数据报无法进入到socket接受缓冲区，此数据报就会被丢弃，udp是没有流量控制的，故UDP的数据传输是不可靠的。 +1. socket 缓冲区 -⑴当客户发送请求报文后，等待服务器的应答，客户进程收到一个应答后，就将其存放到该套接字的接收缓冲区中，此时，如果刚好有其他进程给该客户的这个端口地址发送了一个数据报，则客户的套接字会误以为是服务器的应答，也会将其存放到这个接收缓冲区中。这样在客户的接收缓冲区中会出现噪声数据。 -⑵当客户发送请求报文后，等待服务器的应答，但是由于UDP协议是不可靠的，数据在网络中传输有可能会丢失。 -⑶由于通信前没有事先建立联系，客户在发送请求时不知道服务器的状态。 -⑷由于通信前双方的处理能力未知且没有流量控制机制，发送端发送数据是并不清楚接收端的接收能力，如果快速设备无限制地向慢速设备发送UDP数据报，可能会由于接收方的接收缓冲区溢出而丢失大量数据，而且这种丢失对于通信双方而言都是不清楚的。 \ No newline at end of file +应用程序通过调用send, read方法向网络上发送应用数据，该过程中由于应用程序调用send/write的速度同网络介质发送数据的速度存在差异，所以，应用通过socket发往网络上的的数据会先被缓存，即socket发送缓冲区，等待网络空闲时再发送出去。同样，socket从网络上接受到的数据，也会被缓存，即socket接受缓冲区，等待应用程序把数据从中读出。其中，应用程序调用send发送数据，是将数据拷贝到socket的内核发送缓冲区中，然后send便会返回，即send返回后，数据并不一定发送到目的地去了，send仅仅是把数据拷贝到socket的内核发送缓冲区。 + +2. TCP可靠数据传输原理 + +每个Tcp socket在内核中都有一个发送缓冲区和一个接受缓冲区。tcp协议要求对端在接受到tcp数据报之后，要对其序号进行ACK，只有当接受到一个tcp数据报的ACK之后，才 + +可以把这个tcp数据报从socket的发送缓冲区清除，另外tcp还有一个流量控制功能，tcp的socket接受缓冲区接受到网络上来的数据缓存起来后，如果应用程序一直没有读取，socket接受缓冲区满了之后，发生的动作是：通知对端TCP协议中的窗口关闭，这便是滑动窗口的实现，保证TCP socket接受缓冲区不会溢出，因为对方不允许发送超过所通知窗口大小的数据， 这就是TCP的流量控制，如果对方无视窗口大小而发出了超过窗口大小的数据，则接收方TCP将丢弃它。这两点保证了tcp是可靠传输的。 + +3. UDP不可靠数据传输原理 + +UDP只有一个socket接受缓冲区，没有socket发送缓冲区，即只要有数据就发，不管对方是否可以正确接受。而在对方的socket接受缓冲区满了之后，新来的数据报无法进入到socket接受缓冲区，此数据报就会被丢弃，udp是没有流量控制的，故UDP的数据传输是不可靠的。 \ No newline at end of file diff --git a/interview/network/http.md b/interview/network/http.md index fede4e35..b1ef3142 100644 --- a/interview/network/http.md +++ b/interview/network/http.md @@ -1,6 +1,7 @@ - [Http常见状态码](#http常见状态码) +- [http 和 https 的区别](#http-和-https-的区别) # Http常见状态码 @@ -30,3 +31,7 @@ 500 internal sever error，表示服务器端在执行请求时发生了错误 503 service unavailable，表明服务器暂时处于超负载或正在停机维护，无法处理请求 + +# http 和 https 的区别 + +