work on different mechanisms of accessing the currently authenticated principal

spring-security-rest-custom/src/main/java/org/baeldung/security/AuthenticationFacade.java

@@ -0,0 +1,21 @@
+package org.baeldung.security;
+
+import org.springframework.security.core.Authentication;
+import org.springframework.security.core.context.SecurityContextHolder;
+import org.springframework.stereotype.Component;
+
+@Component
+public class AuthenticationFacade implements IAuthenticationFacade {
+
+    public AuthenticationFacade() {
+        super();
+    }
+
+    // API
+
+    @Override
+    public final Authentication getAuthentication() {
+        return SecurityContextHolder.getContext().getAuthentication();
+    }
+
+}

spring-security-rest-custom/src/main/java/org/baeldung/security/IAuthenticationFacade.java

@@ -0,0 +1,9 @@
+package org.baeldung.security;
+
+import org.springframework.security.core.Authentication;
+
+public interface IAuthenticationFacade {
+
+    Authentication getAuthentication();
+
+}

spring-security-rest-custom/src/main/java/org/baeldung/web/controller/FooController.java

@@ -1,7 +1,5 @@
 package org.baeldung.web.controller;
 
-import javax.servlet.http.HttpServletResponse;
-
 import org.baeldung.web.dto.Foo;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.context.ApplicationEventPublisher;
@@ -10,7 +8,6 @@ import org.springframework.web.bind.annotation.PathVariable;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RequestMethod;
 import org.springframework.web.bind.annotation.ResponseBody;
-import org.springframework.web.util.UriComponentsBuilder;
 
 @Controller
 @RequestMapping(value = "/foo")
@@ -27,7 +24,7 @@ public class FooController {
 
     @RequestMapping(value = "/{id}", method = RequestMethod.GET)
     @ResponseBody
-    public Foo findOne(@PathVariable("id") final Long id, final UriComponentsBuilder uriBuilder, final HttpServletResponse response) {
+    public Foo findOne(@PathVariable("id") final Long id) {
         return new Foo();
     }
 

spring-security-rest-custom/src/main/java/org/baeldung/web/controller/SecurityController1.java

@@ -0,0 +1,39 @@
+package org.baeldung.web.controller;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.context.ApplicationEventPublisher;
+import org.springframework.security.authentication.AnonymousAuthenticationToken;
+import org.springframework.security.core.Authentication;
+import org.springframework.security.core.context.SecurityContextHolder;
+import org.springframework.stereotype.Controller;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestMethod;
+import org.springframework.web.bind.annotation.ResponseBody;
+
+@Controller
+public class SecurityController1 {
+
+    @Autowired
+    private ApplicationEventPublisher eventPublisher;
+
+    public SecurityController1() {
+        super();
+    }
+
+    // API
+
+    @RequestMapping(value = "/username1", method = RequestMethod.GET)
+    @ResponseBody
+    public String currentUserName() {
+        final Authentication authentication = SecurityContextHolder.getContext().getAuthentication();
+        if (!(authentication instanceof AnonymousAuthenticationToken)) {
+            final String currentPrincipalName = authentication.getName();
+            System.out.println("Authentication: " + authentication);
+            System.out.println("Principal: " + authentication.getPrincipal());
+            return currentPrincipalName;
+        }
+
+        return null;
+    }
+
+}

spring-security-rest-custom/src/main/java/org/baeldung/web/controller/SecurityController2.java

@@ -0,0 +1,25 @@
+package org.baeldung.web.controller;
+
+import java.security.Principal;
+
+import org.springframework.stereotype.Controller;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestMethod;
+import org.springframework.web.bind.annotation.ResponseBody;
+
+@Controller
+public class SecurityController2 {
+
+    public SecurityController2() {
+        super();
+    }
+
+    // API
+
+    @RequestMapping(value = "/username2", method = RequestMethod.GET)
+    @ResponseBody
+    public String currentUserNameSimple(final Principal principal) {
+        return principal.getName();
+    }
+
+}

spring-security-rest-custom/src/main/java/org/baeldung/web/controller/SecurityController3.java

@@ -0,0 +1,24 @@
+package org.baeldung.web.controller;
+
+import org.springframework.security.core.Authentication;
+import org.springframework.stereotype.Controller;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestMethod;
+import org.springframework.web.bind.annotation.ResponseBody;
+
+@Controller
+public class SecurityController3 {
+
+    public SecurityController3() {
+        super();
+    }
+
+    // API
+
+    @RequestMapping(value = "/username3", method = RequestMethod.GET)
+    @ResponseBody
+    public String currentUserNameSimple(final Authentication authentication) {
+        return authentication.getName();
+    }
+
+}

spring-security-rest-custom/src/main/java/org/baeldung/web/controller/SecurityController4.java

@@ -0,0 +1,28 @@
+package org.baeldung.web.controller;
+
+import java.security.Principal;
+
+import javax.servlet.http.HttpServletRequest;
+
+import org.springframework.stereotype.Controller;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestMethod;
+import org.springframework.web.bind.annotation.ResponseBody;
+
+@Controller
+public class SecurityController4 {
+
+    public SecurityController4() {
+        super();
+    }
+
+    // API
+
+    @RequestMapping(value = "/username4", method = RequestMethod.GET)
+    @ResponseBody
+    public String currentUserNameSimple(final HttpServletRequest request) {
+        final Principal principal = request.getUserPrincipal();
+        return principal.getName();
+    }
+
+}

spring-security-rest-custom/src/main/java/org/baeldung/web/controller/SecurityController5.java

@@ -0,0 +1,30 @@
+package org.baeldung.web.controller;
+
+import org.baeldung.security.IAuthenticationFacade;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.security.core.Authentication;
+import org.springframework.stereotype.Controller;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestMethod;
+import org.springframework.web.bind.annotation.ResponseBody;
+
+@Controller
+public class SecurityController5 {
+
+    @Autowired
+    private IAuthenticationFacade authenticationFacade;
+
+    public SecurityController5() {
+        super();
+    }
+
+    // API
+
+    @RequestMapping(value = "/username5", method = RequestMethod.GET)
+    @ResponseBody
+    public String currentUserNameSimple() {
+        final Authentication authentication = authenticationFacade.getAuthentication();
+        return authentication.getName();
+    }
+
+}