Implement get customer by id method in CustomerController

Author: LizChe

src/main/java/com/hsbc/simpleapi/controller/CustomerController.java

@@ -1,4 +1,38 @@
 package com.hsbc.simpleapi.controller;
 
+import javax.persistence.EntityNotFoundException;
+
+import org.springframework.beans.factory.annotation.Autowired;
+
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
+import org.springframework.web.server.ResponseStatusException;
+
+import com.hsbc.simpleapi.model.Customer;
+import com.hsbc.simpleapi.service.CustomerService;
+
+@RestController
+@RequestMapping("/api/customer")
 public class CustomerController {
-}
+
+    private CustomerService customerService;
+
+    @Autowired
+    public CustomerController(CustomerService customerService) {
+        this.customerService = customerService;
+    }
+
+    @GetMapping("{id}")
+    public ResponseEntity<Customer> getCustomerById(@PathVariable("id") long id) {
+        try {
+            return new ResponseEntity<>(customerService.getCustomerBy(id), HttpStatus.OK);
+        } catch (EntityNotFoundException e) {
+            throw new ResponseStatusException(HttpStatus.NOT_FOUND, e.getMessage());
+        }
+    }
+}