Spring Boot - API with DB - EmployeeVerse – The Java HRM System

[akash-coded]

🧪 Exercise Title: EmployeeVerse – The Java HRM System

🧩 Context:

You’re the backend engineer at ByteBucks Inc., a quirky but fast-growing tech startup. Your team wants to build a backend service to manage employees across multiple departments. But this isn’t just any CRUD app.

They want the HR dashboard to show cool string summaries, dynamically update data in memory, and follow clean 3-tier architecture (Model, Service, Controller). You’ve been given a Spring Boot skeleton. Now it’s your job to complete it!

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🗃️ Project Structure You Must Follow

src/
└── main/
    └── java/
        └── com.example.employeeverse/
            ├── controller/
            │   └── EmployeeController.java
            ├── model/
            │   └── Employee.java
            ├── service/
            │   ├── EmployeeService.java
            │   └── EmployeeServiceImpl.java
            └── EmployeeverseApplication.java

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🎯 What You'll Learn

• How to use @GetMapping, @RequestParam
• Why we separate responsibilities in layers
• Real usage of toString(), string formatting, and manipulation
• Using collections in the service layer to simulate a database
• Clean code, naming conventions, and comments
• Returning dynamic string responses from APIs

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🛠 Instructions

You are not given the full code. Complete each part step-by-step as per hints.

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👨‍🎓 Step 1: Define Your Employee Model

In model/Employee.java, create a class with the following:

// Create fields: id (int), name (String), department (String), salary (double)
// Generate constructor with all fields
// Add getters and setters for all fields

// Override toString() to return something like:
// "Employee[id=101, name=Ravi, department=Engineering, salary=88000.50]"

Challenge 💡
Use String.format() to format the salary to 2 decimal places.

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🧠 Step 2: Create the Service Interface

In service/EmployeeService.java:

public interface EmployeeService {
    void addEmployee(Employee employee);
    List<Employee> getAllEmployees();
    String getEmployeeSummary(); // Returns all employees as a joined string
    List<String> getAllDepartments(); // Unique department names
    // Add a method to return names starting with a particular letter
}

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🛠 Step 3: Implement the Service

In service/EmployeeServiceImpl.java:

// Use a List<Employee> internally to store the employee objects
// Use a Set<String> to hold unique department names
// For getEmployeeSummary(), return all toString values joined with newline
// Use Java 8 Streams to extract departments, filter names by prefix

Mini Challenge 💡

Add a method:

public double calculateTotalSalary();

Use it in the Controller later.

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🌐 Step 4: Build the Controller

In controller/EmployeeController.java, add endpoints:

// GET /add?name=Ravi&department=Engineering&salary=88000
// Should create a new Employee and add to the service

// GET /list
// Returns a list of all employee string representations

// GET /departments
// Returns a list of unique department names

// GET /filter?startsWith=R
// Returns all employee names that start with the letter R

// GET /total-salary
// Returns the total salary of all employees in a nice sentence

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🧩 Bonus String Puzzles (Integrate in Service or Controller)

1. Count how many employees are from departments ending in -ing (e.g., Engineering, Marketing).
2. Reverse employee names and return as a new list.
3. Return names with vowels removed – just for fun! 😄

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📦 Output Examples

• /list

  Employee[id=101, name=Ravi, department=Engineering, salary=88000.50]
  Employee[id=102, name=Anjali, department=Marketing, salary=76000.00]
  

• /total-salary

  Total Salary Expense: ₹1,64,000.50
  

• /filter?startsWith=A

  Anjali, Aman, Arvind
  

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🧙 Pro Tips (Drop These in Class)

• 🎯 "Service layer helps reuse logic, test independently, and keeps your controller clean."
• 💡 "You’ll thank yourself when testing becomes easier later."
• 🧼 "Always override toString() for debug-friendly models."
• 🧠 "Your controller is like a receptionist – it shouldn’t do heavy lifting."

[akash-coded]

EmployeeVerse_H2_Structure_CheatSheet.pdf

[Sdey0907]

**

Task - Spring Boot - API with DB - EmployeeVerse_Sayan Dey_Completed

**

employeeverse_DB _API_SpringBoot.zip

[prasetha21-max]

PRASETHA N
employeeverse.zip

[vbhavana1]

Springboot_Employeeverse.zip