Решение задачи HashMap 2

src/com/school/faang/hashmap/задача_2/Solution.java

@@ -2,6 +2,18 @@
 
 public class Solution {
     public static void main(String[] args) {
+        UserDatabase userDatabase = new UserDatabase();
 
+        User user1 = new User(1L, "Иван Иванов", "2023-01-15");
+        User user2 = new User(2L, "Петр Петров", "2023-02-20");
+        User user3 = new User(3L, "Мария Сидорова", "2023-03-10");
+        User user4 = new User(4L, "Анна Кузнецова", "2023-04-05");
+
+        userDatabase.addUser(user1);
+        userDatabase.addUser(user2);
+        userDatabase.addUser(user3);
+        userDatabase.addUser(user4);
+
+        userDatabase.printAllUsersFormatted();
     }
 }

src/com/school/faang/hashmap/задача_2/User.java

@@ -0,0 +1,62 @@
+package com.school.faang.hashmap.задача_2;
+
+import java.util.Objects;
+
+class User {
+
+    private long userId;
+    private String fullName;
+    private String registrationDate;
+
+    public User(long userId, String fullName, String registrationDate) {
+        this.userId = userId;
+        this.fullName = fullName;
+        this.registrationDate = registrationDate;
+    }
+
+    public long getUserId() {
+        return userId;
+    }
+
+    public String getFullName() {
+        return fullName;
+    }
+
+    public String getRegistrationDate() {
+        return registrationDate;
+    }
+
+    public void setUserId(long userId) {
+        this.userId = userId;
+    }
+
+    public void setFullName(String fullName) {
+        this.fullName = fullName;
+    }
+
+    public void setRegistrationDate(String registrationDate) {
+        this.registrationDate = registrationDate;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        User user = (User) o;
+        return Objects.equals(fullName, user.fullName);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hashCode(fullName);
+    }
+
+    @Override
+    public String toString() {
+        return "User{" +
+                "userId=" + userId +
+                ", fullName='" + fullName + '\'' +
+                ", registrationDate='" + registrationDate + '\'' +
+                '}';
+    }
+}

src/com/school/faang/hashmap/задача_2/UserDatabase.java

@@ -0,0 +1,28 @@
+package com.school.faang.hashmap.задача_2;
+
+import java.util.HashMap;
+import java.util.Map;
+
+public class UserDatabase {
+    private Map<String, User> myDataBase = new HashMap<>();
+
+    public void addUser(User user) {
+        if (user == null) {
+            throw new IllegalArgumentException("Где информация о пользователе?");
+        }
+        if (myDataBase.containsKey(user.getFullName())) {
+            throw new IllegalArgumentException("Пользователь с именем '" +
+                    user.getFullName() + "' уже есть в базе данных");
+        } else {
+            myDataBase.put(user.getFullName(), user);
+        }
+    }
+
+    // "Пользователь @username, полное имя: Full Name"
+    public void printAllUsersFormatted() {
+        for (Map.Entry<String, User> entry : myDataBase.entrySet()) {
+            String username = "@" + entry.getKey().toLowerCase().replace(" ", "_");
+            System.out.println("Пользователь " + username + ", полное имя: " + entry.getKey());
+        }
+    }
+}