examples

pom.xml

@@ -27,9 +27,8 @@
         </dependency>
 
         <dependency>
-            <groupId>org.postgresql</groupId>
+            <groupId>com.h2database</groupId>
-            <artifactId>postgresql</artifactId>
+            <artifactId>h2</artifactId>
-            <scope>runtime</scope>
         </dependency>
         <dependency>
             <groupId>org.projectlombok</groupId>
@@ -40,12 +39,12 @@
         <dependency>
             <groupId>io.swagger.core.v3</groupId>
             <artifactId>swagger-annotations</artifactId>
-            <version>2.2.4</version>
+            <version>2.2.6</version>
         </dependency>
         <dependency>
             <groupId>org.springdoc</groupId>
             <artifactId>springdoc-openapi-ui</artifactId>
-            <version>1.6.11</version>
+            <version>1.6.12</version>
         </dependency>
     </dependencies>
 

request/requests.http

@@ -0,0 +1,19 @@
+### Получить первую страницу из 3 элементов
+GET http://localhost:8080/api/post?offset=0&limit=3
+Content-Type: application/json
+
+### Получить вторую страницу из 3 элементов с сортировкой
+GET http://localhost:8080/api/post/exampleSort?offset=1&limit=3&sort=createOn
+Content-Type: application/json
+
+### Получить вторую страницу из 3 элементов с сортировкой (enum)
+GET http://localhost:8080/api/post/exampleEnumSort?offset=1&limit=3&sort=ID_ASC
+Content-Type: application/json
+
+### Получить вторую страницу из 3 элементов JPQL
+GET http://localhost:8080/api/post/exampleJpql?offset=1&limit=3&title=Post
+Content-Type: application/json
+
+### Получить вторую страницу из 3 элементов SQL Native
+GET http://localhost:8080/api/post/exampleSqlNative?offset=1&limit=3&title=Post
+Content-Type: application/json

sql_examples.sql

@@ -0,0 +1,34 @@
+EXPLAIN ANALYSE
+SELECT *
+FROM post
+ORDER BY create_on
+    FETCH FIRST 50 ROWS ONLY;
+
+EXPLAIN ANALYSE
+SELECT *
+FROM post
+ORDER BY create_on
+OFFSET 50 ROWS FETCH NEXT 50 ROWS ONLY;
+
+EXPLAIN ANALYSE
+SELECT *
+FROM post
+ORDER BY create_on
+OFFSET 9950 ROWS FETCH NEXT 50 ROWS ONLY;
+
+CREATE INDEX idx_post_created_on ON post (create_on DESC);
+
+CREATE INDEX idx_post_created_on ON post (create_on DESC, id DESC);
+
+EXPLAIN ANALYSE
+SELECT *
+FROM post
+ORDER BY create_on DESC, id DESC
+    FETCH FIRST 50 ROWS ONLY;
+
+EXPLAIN ANALYSE
+SELECT *
+FROM post
+WHERE (create_on, id) < ('2022-10-30 00:11:43.224314', '8766d496-44c7-4e48-af29-b19178692cd9')
+ORDER BY create_on DESC
+    FETCH FIRST 50 ROWS ONLY

src/main/java/dev/struchkov/example/GeneratorPost.java

@@ -1,9 +1,14 @@
 package dev.struchkov.example;
 
 import lombok.RequiredArgsConstructor;
+import org.springframework.context.event.ContextRefreshedEvent;
+import org.springframework.context.event.EventListener;
 import org.springframework.stereotype.Component;
+import org.springframework.transaction.annotation.Transactional;
 
 import java.time.LocalDateTime;
+import java.util.ArrayList;
+import java.util.List;
 import java.util.UUID;
 
 @Component
@@ -12,14 +17,18 @@ public class GeneratorPost {
 
     private final PostRepository postRepository;
 
-    public void generate() {
+    @Transactional
+    @EventListener
+    public void generate(ContextRefreshedEvent event) {
+        final List<Post> posts = new ArrayList<>();
         for (int i = 0; i < 10000; i++) {
             final Post post = new Post();
             post.setId(UUID.randomUUID());
             post.setTitle("Post " + i);
             post.setCreateOn(LocalDateTime.now().minusDays(1L).plusMinutes(i));
-            postRepository.save(post);
+            posts.add(post);
         }
+        postRepository.saveAll(posts);
     }
 
 }

src/main/java/dev/struchkov/example/PostController.java

@@ -3,30 +3,67 @@ package dev.struchkov.example;
 import lombok.RequiredArgsConstructor;
 import org.springframework.data.domain.Page;
 import org.springframework.data.domain.PageRequest;
+import org.springframework.data.domain.Sort;
 import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RequestParam;
 import org.springframework.web.bind.annotation.RestController;
 
+import javax.validation.constraints.Min;
+
 @RestController
 @RequestMapping("api/post")
 @RequiredArgsConstructor
 public class PostController {
 
     private final PostRepository repository;
-    private final GeneratorPost generatorPost;
-
-    @GetMapping("generate")
-    public void generate() {
-        generatorPost.generate();
-    }
 
     @GetMapping
     public Page<Post> getAll(
-            @RequestParam("offset") Integer offset,
+            @RequestParam(value = "offset", defaultValue = "0") @Min(0) Integer offset,
-            @RequestParam("limit") Integer limit
+            @RequestParam(value = "limit", defaultValue = "20") Integer limit
     ) {
         return repository.findAll(PageRequest.of(offset, limit));
     }
 
+    @GetMapping("exampleSort")
+    public Page<Post> getAllAndSort(
+            @RequestParam("offset") Integer offset,
+            @RequestParam("limit") Integer limit,
+            @RequestParam("sort") String sortField
+    ) {
+        return repository.findAll(
+                PageRequest.of(offset, limit, Sort.by(Sort.Direction.ASC, sortField))
+        );
+    }
+
+    @GetMapping("exampleEnumSort")
+    public Page<Post> getAllAndEnumSort(
+            @RequestParam("offset") Integer offset,
+            @RequestParam("limit") Integer limit,
+            @RequestParam("sort") PostSort sort
+    ) {
+        return repository.findAll(
+                PageRequest.of(offset, limit, sort.getSortValue())
+        );
+    }
+
+    @GetMapping("exampleJpql")
+    public Page<Post> getAllJpql(
+            @RequestParam("title") String title,
+            @RequestParam("offset") Integer offset,
+            @RequestParam("limit") Integer limit
+    ) {
+        return repository.findAllByTitleJpql(title, PageRequest.of(offset, limit));
+    }
+
+    @GetMapping("exampleSqlNative")
+    public Page<Post> getAllSqlNative(
+            @RequestParam("title") String title,
+            @RequestParam("offset") Integer offset,
+            @RequestParam("limit") Integer limit
+    ) {
+        return repository.findAllByTitleNative(title, PageRequest.of(offset, limit));
+    }
+
 }

src/main/java/dev/struchkov/example/PostRepository.java

@@ -1,9 +1,25 @@
 package dev.struchkov.example;
 
+import org.springframework.data.domain.Page;
+import org.springframework.data.domain.Pageable;
 import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.data.jpa.repository.Query;
+import org.springframework.data.repository.query.Param;
 
 import java.util.UUID;
 
 public interface PostRepository extends JpaRepository<Post, UUID> {
 
+    Page<Post> findAllByTitleLikeIgnoreCase(String titleLike, Pageable pageable);
+
+    @Query("SELECT p FROM Post p WHERE p.title like %:title%")
+    Page<Post> findAllByTitleJpql(@Param("title") String title, Pageable pageable);
+
+    @Query(
+            nativeQuery = true,
+            value = "SELECT * FROM POST WHERE TITLE LIKE %?1%",
+            countQuery = "SELECT count(*) FROM POST WHERE TITLE LIKE %?1%"
+    )
+    Page<Post> findAllByTitleNative(String title, Pageable pageable);
+
 }

src/main/java/dev/struchkov/example/PostSort.java

@@ -0,0 +1,17 @@
+package dev.struchkov.example;
+
+import lombok.Getter;
+import lombok.RequiredArgsConstructor;
+import org.springframework.data.domain.Sort;
+
+@Getter
+@RequiredArgsConstructor
+public enum PostSort {
+
+    ID_ASC(Sort.by(Sort.Direction.ASC, "id")),
+    ID_DESC(Sort.by(Sort.Direction.DESC, "id")),
+    DATE_ASC(Sort.by(Sort.Direction.ASC, "createOn"));
+
+    private final Sort sortValue;
+
+}

src/main/java/dev/struchkov/example/SpringPaginationApplication.java

@@ -1,8 +1,11 @@
 package dev.struchkov.example;
 
+import org.h2.tools.Server;
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
-import org.springframework.scheduling.annotation.EnableScheduling;
+import org.springframework.context.annotation.Bean;
+
+import java.sql.SQLException;
 
 @SpringBootApplication
 public class SpringPaginationApplication {
@@ -11,4 +14,9 @@ public class SpringPaginationApplication {
         SpringApplication.run(SpringPaginationApplication.class, args);
     }
 
+    @Bean(initMethod = "start", destroyMethod = "stop")
+    public Server inMemoryH2DatabaseServer() throws SQLException {
+        return Server.createTcpServer("-tcp", "-tcpAllowOthers", "-tcpPort", "9092");
+    }
+
 }

src/main/resources/application.yml

@@ -1,13 +1,18 @@
 spring:
   datasource:
-    driver-class-name: org.postgresql.Driver
+    driver-class-name: org.h2.Driver
-    url: jdbc:postgresql://localhost:5432/test
+    url: jdbc:h2:mem:demo
-    username: ${DB_USERNAME}
+    username: sa
-    password: ${DB_PASSWORD}
+    password: password
   jpa:
     hibernate:
-      ddl-auto: update
+      ddl-auto: create-drop
     show-sql: true
     properties:
       hibernate:
         format_sql: true
+logging:
+  level:
+    org:
+      hibernate:
+        type: trace