Upload some example codes of java.

Java/Lesson/Code/Main.java

@@ -0,0 +1,162 @@
+import java.util.*;
+import java.lang.*;
+
+class FormatPath {
+    Vector<String> path;
+    String input;
+    String output;
+
+    public FormatPath(String s) {
+        this.input = s.replace('\\','/');
+        this.path = new Vector<String>();
+        this.output = "";
+        try {
+            this.deal();
+        } catch (Exception e) {
+            this.output = "Value Error";
+        }
+    }
+
+    private void deal() throws Exception {
+        if (this.input.length() == 0) {
+            throw new Exception("Empty.");
+        }
+
+        int cursor;
+        int start;
+        int end;
+        start = 0;
+        end = 0;
+        if (this.input.length() > 1) {
+            if (this.input.charAt(0) == '/') {
+                this.output = "/";
+            }
+            for (cursor = 1; cursor < this.input.length(); cursor++) {
+                switch (this.input.charAt(cursor - 1)){
+                    case '/':
+                        start = cursor;
+                        break;
+                    case '.':
+                        if (this.input.charAt(cursor) == '.') {
+                            if (this.path.isEmpty()) {
+                                throw new Exception("Wrong Expression.");
+                            }
+                            this.path.remove(this.path.size() - 1);
+                        }
+                        break;
+                    default:
+                        if (this.input.charAt(cursor) == '/') {
+                            end = cursor;
+                            this.path.add(this.input.substring(start, end));
+                        }
+                        break;
+                }
+
+            }
+            if (start < this.input.length() && this.input.charAt(this.input.length() - 1) != '/') {
+                if (!this.input.substring(start).equals("/") && !this.input.substring(start).equals(".")) {
+                    this.path.add(this.input.substring(start));
+                }
+                if (this.input.substring(start).equals("..")) {
+                    if (this.path.isEmpty()) {
+                        throw new Exception("Wrong Expression.");
+                    }
+                    this.path.remove(this.path.size() - 1);
+                }
+            }
+        } else {
+            if (!this.input.equals(".")) {
+                this.path.add(this.input);
+            }
+        }
+
+        for (cursor = 0; cursor < this.path.size(); cursor++) {
+            this.output += this.path.get(cursor) + "/";
+        }
+
+        if (this.path.size() != 0) {
+            this.output = this.output.substring(0, this.output.length() - 1);
+        }
+
+    }
+
+    public String getOutput() {
+        return this.output;
+    }
+}
+
+public class Main {
+    public static void main(String []args) {
+        System.out.println("Java 2020.");
+        Scanner scanner = new Scanner(System.in);
+        while (scanner.hasNext()) {
+            String string = scanner.nextLine();
+            FormatPath path = new FormatPath(string);
+            System.out.println(path.getOutput());
+        }
+    }
+}
+
+// Powered by Intellij IDEA Community Edition 2020.1.
+
+//./jisuanke\\./suantou/../bin/
+//..
+///\./\.\/.\/
+
+//测评信息
+//        ================================================
+//        测评用例 1：答案错误 [165.000 毫秒，10896 KB]
+//        用例输入：
+//        a\\B
+//        \\\\A\\\\B
+//        \\\\A\\\\B
+//
+//        用例正确输出：
+//        a/B
+//        /A/b
+//        /A/B
+//
+//        你的输出：
+//        a
+//        /A
+//        /A
+//        ---------------------------
+//        测评用例 2：答案错误 [143.000 毫秒，10900 KB]
+//        ---------------------------
+//        测评用例 3：答案错误 [129.000 毫秒，10908 KB]
+//        ---------------------------
+//        测评用例 4：答案错误 [152.000 毫秒，10932 KB]
+//        ---------------------------
+//        测评用例 5：答案错误 [159.000 毫秒，10880 KB]
+//        ---------------------------
+//        测评用例 6：答案错误 [155.000 毫秒，10908 KB]
+//
+//        结果
+//        ================================================
+//        共 6 组测评用例，通过 0 组。
+//
+//        /
+//        .
+//        /.
+//        1/..
+//        1/../
+//        /1/..
+//        /1/../
+//
+//        用例正确输出：
+//        /
+//
+//        /
+//
+//
+//        /
+//        /
+//
+//        你的输出：
+//        /
+//        .
+//        /
+//
+//
+//        /
+//        /

Java/Lesson/Code/SQL.java

@@ -0,0 +1,41 @@
+import java.sql.*;
+
+public class SQL {
+    public static void main(String []args) {
+        int status = 1;
+        try {
+            if (status == 0) {
+                throw new Exception("");
+            }
+            String url = "jdbc:mysql://localhost:3306/jpetstore?autoReconnect=true";
+        }
+        catch (Exception e) {
+            e.printStackTrace();
+        }
+
+//        String mysql = "jdbc:mysql://localhost:3306/mail?user=root&password=root";
+        String mysql = "jdbc:mysql://localhost:3306/mail?serverTimezone=Asia/Shanghai";
+        String user = "root";
+        String passwd = "root";
+        try {
+            Class.forName("com.mysql.cj.jdbc.Driver");
+            System.out.println("OK Load Finished.");
+            Connection connection = DriverManager.getConnection(mysql,user,passwd);
+            Statement statement = connection.createStatement();
+            String sql = "select * from goods";
+            ResultSet resultSet = statement.executeQuery(sql);
+            while (resultSet.next()) {
+                System.out.println(resultSet.getString("Goods_ID"));
+                System.out.println(resultSet.getString("Goods_Type"));
+            }
+            statement.execute("insert into purchaser values(0,'Tom');");
+//            statement.execute("update purchaser set purchaser_name = 'Tommy' where purchaser_name = 'Tom';");
+            resultSet.close();
+            statement.close();
+            connection.close();
+        }
+        catch (Exception e) {
+            e.printStackTrace();
+        }
+    }
+}

Java/Lesson/Code/Web.java

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+import java.net.InetAddress;
+import java.net.MalformedURLException;
+import java.net.URL;
+
+import java.net.*;
+import java.io.*;
+import java.util.Scanner;
+
+public class Web {
+    public static void main(String []args){
+        int no1 = 0;
+        try {
+            if (no1 == 0) throw new Exception("");
+            URL web = new URL("https://www.nankai.edu.cn");
+            System.out.println(web.getProtocol());
+            System.out.println(web.getHost());
+            System.out.println(web.getPort());
+            System.out.println(web.getFile());
+            BufferedReader in = new BufferedReader(new InputStreamReader(web.openStream()));
+            String inputLine;
+            //while ((inputLine = in.readLine()) != null) System.out.println(inputLine);
+            in.close();
+            URLConnection urlConnection = web.openConnection();
+            BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(urlConnection.getInputStream()));
+            while ((inputLine = bufferedReader.readLine()) != null) {
+//                System.out.println(inputLine);
+            }
+            bufferedReader.close();
+        }
+        catch (Exception e) {
+            // This is try to read web file lines.
+            // Two methods are the same result.
+        }
+        try {
+            if (no1 == 0) throw new Exception("");
+            InetAddress inetAddress = InetAddress.getLocalHost();
+            System.out.println(inetAddress);
+            byte[] address = inetAddress.getAddress();
+            for (int i = 0; i < address.length ; i++) {
+                System.out.println(address[i]);
+            }
+            System.out.println(inetAddress.getHostName());
+            System.out.println(inetAddress.getHostAddress());
+        }
+        catch (Exception e) {
+
+        }
+        try {
+            URL url = new URL("https://www.baidu.com/");
+            System.out.println(url);
+            URL baseUrl = new URL(url,"file.html");
+            System.out.println(baseUrl);
+
+            URL socketUrl = new URL("https://101.200.100.121:8080");
+            System.out.println(socketUrl);
+            System.out.println(socketUrl.getProtocol());
+            System.out.println(socketUrl.getHost());
+            System.out.println(socketUrl.getPort());
+            System.out.println(socketUrl.getFile());
+            System.out.println(socketUrl.getRef());
+        }
+        catch (MalformedURLException e) {
+
+        }
+        try {
+            System.out.println("First");
+//            Socket socket = new Socket("101.200.155.187",8080);
+
+            System.out.println("Local Host");
+            ServerSocket serverSocket = new ServerSocket(8080);
+            System.out.println(serverSocket);
+            System.out.println(serverSocket.getLocalSocketAddress());
+            System.out.println(serverSocket.getLocalPort());
+            serverSocket.close();
+        }
+        catch (Exception e) {
+
+        }
+    }
+}
+
+
+
+class TestUrl {
+    public static void main(String[] args) throws Exception {
+        URL web = new
+                URL("http://www.nankai.edu.cn");
+        System.out.println(web.getProtocol());
+        System.out.println(web.getHost());
+        System.out.println(web.getPort());
+        System.out.println(web.getFile());
+        BufferedReader in = new BufferedReader(
+                new InputStreamReader(web.openStream()));
+                String inputLine;
+                while ((inputLine = in.readLine()) != null)
+                    System.out.println(inputLine);
+                in.close();
+    }
+}