Spring 5 reff (#1786)

* Fix Spring5 snippets

* Refactor Spring 5 samples

* Refactor Spring 5 samples

* Enable Spring5

spring-5/src/main/java/com/baeldung/functional/FormHandler.java

@@ -18,33 +18,24 @@ public class FormHandler {
         return request
           .body(toFormData())
           .map(MultiValueMap::toSingleValueMap)
-          .map(formData -> {
-              System.out.println("form data: " + formData.toString());
-              if ("baeldung".equals(formData.get("user")) && "you_know_what_to_do".equals(formData.get("token"))) {
-                  return ok()
-                    .body(Mono.just("welcome back!"), String.class)
-                    .block();
-              }
-              return ServerResponse
-                .badRequest()
-                .build()
-                .block();
-          });
+          .filter(formData -> "baeldung".equals(formData.get("user")))
+          .filter(formData -> "you_know_what_to_do".equals(formData.get("token")))
+          .flatMap(formData -> ok().body(Mono.just("welcome back!"), String.class))
+          .or(ServerResponse.badRequest().build());
     }
 
     Mono<ServerResponse> handleUpload(ServerRequest request) {
         return request
           .body(toDataBuffers())
           .collectList()
-          .map(dataBuffers -> {
+          .flatMap(dataBuffers -> {
               AtomicLong atomicLong = new AtomicLong(0);
               dataBuffers.forEach(d -> atomicLong.addAndGet(d
                 .asByteBuffer()
                 .array().length));
-              System.out.println("data length:" + atomicLong.get());
+
               return ok()
-                .body(fromObject(atomicLong.toString()))
-                .block();
+                .body(fromObject(atomicLong.toString()));
           });
     }
 }

spring-5/src/main/java/com/baeldung/web/FooController.java

@@ -1,26 +1,15 @@
 package com.baeldung.web;
 
-import java.util.List;
-import java.util.Optional;
-
-import javax.validation.constraints.Max;
-import javax.validation.constraints.Min;
-
+import com.baeldung.persistence.FooRepository;
 import org.springframework.beans.factory.annotation.Autowired;
-import org.springframework.data.domain.Page;
 import org.springframework.data.domain.PageRequest;
 import org.springframework.http.HttpStatus;
 import org.springframework.validation.annotation.Validated;
-import org.springframework.web.bind.annotation.PathVariable;
-import org.springframework.web.bind.annotation.RequestBody;
-import org.springframework.web.bind.annotation.RequestMapping;
-import org.springframework.web.bind.annotation.RequestMethod;
-import org.springframework.web.bind.annotation.RequestParam;
-import org.springframework.web.bind.annotation.ResponseBody;
-import org.springframework.web.bind.annotation.ResponseStatus;
-import org.springframework.web.bind.annotation.RestController;
+import org.springframework.web.bind.annotation.*;
 
-import com.baeldung.persistence.FooRepository;
+import javax.validation.constraints.Max;
+import javax.validation.constraints.Min;
+import java.util.List;
 
 @RestController("/foos")
 public class FooController {
@@ -30,30 +19,29 @@ public class FooController {
 
     // API - read
 
-    @RequestMapping(method = RequestMethod.GET, value = "/foos/{id}")
+    @GetMapping("/foos/{id}")
     @ResponseBody
     @Validated
     public Foo findById(@PathVariable @Min(0) final long id) {
-        return repo.findOne(id).orElse(null);
+        return repo.findById(id).orElse(null);
     }
 
-    @RequestMapping(method = RequestMethod.GET)
+    @GetMapping
     @ResponseBody
     public List<Foo> findAll() {
         return repo.findAll();
     }
 
-    @RequestMapping(params = { "page", "size" }, method = RequestMethod.GET)
+    @GetMapping(params = { "page", "size" })
     @ResponseBody
     @Validated
     public List<Foo> findPaginated(@RequestParam("page") @Min(0) final int page, @Max(100) @RequestParam("size") final int size) {
-        final Page<Foo> resultPage = repo.findAll(new PageRequest(page, size));
-        return resultPage.getContent();
+        return repo.findAll(PageRequest.of(page, size)).getContent();
     }
 
     // API - write
 
-    @RequestMapping(method = RequestMethod.PUT, value = "/foos/{id}")
+    @PutMapping("/foos/{id}")
     @ResponseStatus(HttpStatus.OK)
     @ResponseBody
     public Foo update(@PathVariable("id") final String id, @RequestBody final Foo foo) {