REST Pagination in Spring

spring/rest-pagination/.gitignore

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+/target/
+!.mvn/wrapper/maven-wrapper.jar
+
+### STS ###
+.apt_generated
+.classpath
+.factorypath
+.project
+.settings
+.springBeans
+.sts4-cache
+
+### IntelliJ IDEA ###
+.idea
+*.iws
+*.iml
+*.ipr
+
+### NetBeans ###
+/nbproject/private/
+/build/
+/nbbuild/
+/dist/
+/nbdist/
+/.nb-gradle/

spring/rest-pagination/pom.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <groupId>com.javadevjournal</groupId>
+    <artifactId>rest-pagination</artifactId>
+    <version>0.0.1-SNAPSHOT</version>
+    <packaging>jar</packaging>
+
+    <name>REST Pagnination With Spring</name>
+    <description>Project demonstrating how to build pagination in Spring powered REST API</description>
+
+    <parent>
+        <groupId>org.springframework.boot</groupId>
+        <artifactId>spring-boot-starter-parent</artifactId>
+        <version>2.0.2.RELEASE</version>
+        <relativePath/> <!-- lookup parent from repository -->
+    </parent>
+
+    <properties>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
+        <java.version>1.8</java.version>
+    </properties>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-data-jpa</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-data-rest</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-hateoas</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-web</artifactId>
+        </dependency>
+
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-devtools</artifactId>
+            <scope>runtime</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.hsqldb</groupId>
+            <artifactId>hsqldb</artifactId>
+            <scope>runtime</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-test</artifactId>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.springframework.boot</groupId>
+                <artifactId>spring-boot-maven-plugin</artifactId>
+            </plugin>
+        </plugins>
+    </build>
+
+
+</project>

spring/rest-pagination/src/main/java/com/javadevjournal/rest/RestPagninationWithSpringApplication.java

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+package com.javadevjournal.rest;
+
+import com.javadevjournal.rest.jpa.ProductRepository;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class RestPagninationWithSpringApplication {
+
+
+    public static void main(String[] args) {
+        SpringApplication.run(RestPagninationWithSpringApplication.class, args);
+    }
+}

spring/rest-pagination/src/main/java/com/javadevjournal/rest/assembler/ProductResourceAssembler.java

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+package com.javadevjournal.rest.assembler;
+
+import com.javadevjournal.rest.controller.ProductRESTController;
+import com.javadevjournal.rest.data.ProductData;
+import com.javadevjournal.rest.entity.ProductEntity;
+import org.springframework.hateoas.Resource;
+import org.springframework.hateoas.mvc.ResourceAssemblerSupport;
+import org.springframework.stereotype.Component;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import static org.springframework.hateoas.mvc.ControllerLinkBuilder.linkTo;
+import static org.springframework.hateoas.mvc.ControllerLinkBuilder.methodOn;
+
+@Component
+public class ProductResourceAssembler{
+
+
+}

spring/rest-pagination/src/main/java/com/javadevjournal/rest/controller/ProductRESTController.java

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+package com.javadevjournal.rest.controller;
+
+import com.javadevjournal.rest.entity.ProductEntity;
+import com.javadevjournal.rest.service.ProductService;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.data.domain.Page;
+import org.springframework.data.domain.Pageable;
+import org.springframework.data.web.PagedResourcesAssembler;
+import org.springframework.hateoas.*;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.MediaType;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+import static org.springframework.hateoas.mvc.ControllerLinkBuilder.linkTo;
+import static org.springframework.hateoas.mvc.ControllerLinkBuilder.methodOn;
+
+
+@RestController
+public class ProductRESTController {
+
+    @Autowired
+    private ProductService productService;
+
+    @Autowired private EntityLinks links;
+
+    @GetMapping(value = "/products",produces =MediaType.APPLICATION_JSON_VALUE)
+    public ResponseEntity<PagedResources<ProductEntity>> AllProducts(Pageable pageable, PagedResourcesAssembler assembler){
+        Page<ProductEntity> products = productService.findAllProducts(pageable);
+        PagedResources<ProductEntity> pr= assembler.toResource(products,linkTo(ProductRESTController.class).slash("/products").withSelfRel());
+        HttpHeaders responseHeaders = new HttpHeaders();
+        responseHeaders.add("Link",createLinkHeader(pr));
+        return new ResponseEntity<>(assembler.toResource(products,linkTo(ProductRESTController.class).slash("/products").withSelfRel()),responseHeaders,HttpStatus.OK);
+    }
+
+    private String createLinkHeader(PagedResources<ProductEntity> pr){
+        final StringBuilder linkHeader = new StringBuilder();
+        linkHeader.append(buildLinkHeader(  pr.getLinks("first").get(0).getHref(),"first"));
+        linkHeader.append(", ");
+        linkHeader.append(buildLinkHeader( pr.getLinks("next").get(0).getHref(),"next"));
+        return linkHeader.toString();
+    }
+
+    public static String buildLinkHeader(final String uri, final String rel) {
+        return "<" + uri + ">; rel=\"" + rel + "\"";
+    }
+}

spring/rest-pagination/src/main/java/com/javadevjournal/rest/data/ProductData.java

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+package com.javadevjournal.rest.data;
+
+import com.javadevjournal.rest.entity.ProductEntity;
+import org.springframework.hateoas.ResourceSupport;
+
+import java.util.List;
+
+public class ProductData extends ResourceSupport {
+
+
+    List<ProductEntity> products;
+    private int pageNumber;
+    private int size;
+    private int totalPages;
+    private int totalElements;
+
+    public ProductData(List<ProductEntity> products, int pageNumber, int size, int totalPages, int totalElements) {
+        this.products = products;
+        this.pageNumber = pageNumber;
+        this.size = size;
+        this.totalPages = totalPages;
+        this.totalElements = totalElements;
+    }
+
+    public List<ProductEntity> getProducts() {
+        return products;
+    }
+
+    public int getPageNumber() {
+        return pageNumber;
+    }
+
+    public int getSize() {
+        return size;
+    }
+
+    public int getTotalPages() {
+        return totalPages;
+    }
+
+    public int getTotalElements() {
+        return totalElements;
+    }
+}

spring/rest-pagination/src/main/java/com/javadevjournal/rest/entity/ProductEntity.java

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+package com.javadevjournal.rest.entity;
+
+import javax.persistence.*;
+import java.util.Objects;
+
+@Entity
+@Table(name = "product")
+public class ProductEntity {
+
+    @Id
+    @GeneratedValue
+    private Integer id;
+
+    @Column
+    private String code;
+
+    @Column
+    private String name;
+
+    @Column
+    private String description;
+
+    @Column
+    private Double price;
+
+    @Column
+    private Integer stock;
+
+    public String getCode() {
+        return code;
+    }
+
+    public void setCode(String code) {
+        this.code = code;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public String getDescription() {
+        return description;
+    }
+
+    public void setDescription(String description) {
+        this.description = description;
+    }
+
+    public Double getPrice() {
+        return price;
+    }
+
+    public void setPrice(Double price) {
+        this.price = price;
+    }
+
+    public Integer getStock() {
+        return stock;
+    }
+
+    public void setStock(Integer stock) {
+        this.stock = stock;
+    }
+
+    public Integer getId() {
+        return id;
+    }
+
+    public void setId(Integer id) {
+        this.id = id;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (!(o instanceof ProductEntity)) return false;
+        ProductEntity that = (ProductEntity) o;
+        return Objects.equals(id, that.id) &&
+                Objects.equals(getCode(), that.getCode()) &&
+                Objects.equals(getName(), that.getName()) &&
+                Objects.equals(getDescription(), that.getDescription()) &&
+                Objects.equals(getPrice(), that.getPrice()) &&
+                Objects.equals(getStock(), that.getStock());
+    }
+
+    @Override
+    public int hashCode() {
+
+        return Objects.hash(id, getCode(), getName(), getDescription(), getPrice(), getStock());
+    }
+}

spring/rest-pagination/src/main/java/com/javadevjournal/rest/event/PostConstructBean.java

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+package com.javadevjournal.rest.event;
+
+import com.javadevjournal.rest.entity.ProductEntity;
+import com.javadevjournal.rest.jpa.ProductRepository;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Component;
+
+import javax.annotation.PostConstruct;
+import java.util.ArrayList;
+import java.util.List;
+
+@Component
+public class PostConstructBean {
+
+    @Autowired
+    private ProductRepository productRepository;
+
+    @PostConstruct
+    public void init(){
+
+        List<ProductEntity> productEntityList = new ArrayList<>();
+        for(int i = 0; i<100; i++){
+            ProductEntity product = new ProductEntity();
+            product.setCode(String.valueOf(i));
+            product.setDescription("Description of Product "+i);
+            product.setName("Name "+i);
+            product.setPrice(i+10.00);
+            product.setStock(i+2);
+            productEntityList.add(product);
+        }
+
+        productRepository.saveAll(productEntityList);
+
+        Iterable<ProductEntity> pro=  productRepository.findAll();
+        pro.forEach(System.out::println);
+    }
+}

spring/rest-pagination/src/main/java/com/javadevjournal/rest/jpa/ProductRepository.java

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+package com.javadevjournal.rest.jpa;
+
+import com.javadevjournal.rest.entity.ProductEntity;
+import org.springframework.data.repository.PagingAndSortingRepository;
+
+public interface ProductRepository extends PagingAndSortingRepository<ProductEntity,Integer> {
+}

spring/rest-pagination/src/main/java/com/javadevjournal/rest/service/DefaultProductService.java

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+package com.javadevjournal.rest.service;
+
+import com.javadevjournal.rest.entity.ProductEntity;
+import com.javadevjournal.rest.jpa.ProductRepository;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.data.domain.Page;
+import org.springframework.data.domain.Pageable;
+import org.springframework.stereotype.Service;
+
+@Service
+public class DefaultProductService implements ProductService {
+
+    @Autowired
+    private ProductRepository productRepository;
+
+    @Override
+    public Page<ProductEntity> findAllProducts(Pageable pageable) {
+        return productRepository.findAll(pageable);
+    }
+
+    public ProductRepository getProductRepository() {
+        return productRepository;
+    }
+}

spring/rest-pagination/src/main/java/com/javadevjournal/rest/service/ProductService.java

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+package com.javadevjournal.rest.service;
+
+import com.javadevjournal.rest.entity.ProductEntity;
+import org.springframework.data.domain.Page;
+import org.springframework.data.domain.Pageable;
+
+public interface ProductService {
+
+    public Page<ProductEntity> findAllProducts(Pageable pageable);
+}

spring/rest-pagination/src/test/java/com/javadevjournal/rest/RestPagninationWithSpringApplicationTests.java

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+package com.javadevjournal.rest;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.test.context.junit4.SpringRunner;
+
+@RunWith(SpringRunner.class)
+@SpringBootTest
+public class RestPagninationWithSpringApplicationTests {
+
+    @Test
+    public void contextLoads() {
+    }
+
+}