adding some simple persistence

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

@@ -0,0 +1,62 @@
+package com.baeldung.web;
+
+import java.util.List;
+
+import javax.validation.constraints.Max;
+import javax.validation.constraints.Min;
+
+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 com.baeldung.persistence.FooRepository;
+
+@RestController("/foos")
+public class FooController {
+
+    @Autowired
+    private FooRepository repo;
+
+    // API - read
+
+    @RequestMapping(method = RequestMethod.GET, value = "/foos/{id}")
+    @ResponseBody
+    @Validated
+    public Foo findById(@PathVariable @Min(0) final long id) {
+        return repo.findOne(id);
+    }
+
+    @RequestMapping(method = RequestMethod.GET)
+    @ResponseBody
+    public List<Foo> findAll() {
+        return repo.findAll();
+    }
+
+    @RequestMapping(params = { "page", "size" }, method = RequestMethod.GET)
+    @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();
+    }
+
+    // API - write
+
+    @RequestMapping(method = RequestMethod.PUT, value = "/foos/{id}")
+    @ResponseStatus(HttpStatus.OK)
+    @ResponseBody
+    public Foo update(@PathVariable("id") final String id, @RequestBody final Foo foo) {
+        return foo;
+    }
+
+}