spring data rest projections

spring-data-rest/src/main/java/com/baeldung/config/RestConfig.java

@@ -0,0 +1,17 @@
+package com.baeldung.config;
+
+import org.springframework.context.annotation.Configuration;
+import org.springframework.data.rest.core.config.RepositoryRestConfiguration;
+import org.springframework.data.rest.webmvc.config.RepositoryRestConfigurerAdapter;
+
+import com.baeldung.projections.CustomBook;
+
+
+@Configuration
+public class RestConfig extends RepositoryRestConfigurerAdapter{
+
+    @Override
+    public void configureRepositoryRestConfiguration(RepositoryRestConfiguration repositoryRestConfiguration){
+        repositoryRestConfiguration.getProjectionConfiguration().addProjection(CustomBook.class);
+    }
+}

spring-data-rest/src/main/java/com/baeldung/models/Book.java

@@ -4,6 +4,7 @@ import java.util.List;
 
 import javax.persistence.Column;
 import javax.persistence.Entity;
+import javax.persistence.FetchType;
 import javax.persistence.GeneratedValue;
 import javax.persistence.GenerationType;
 import javax.persistence.Id;
@@ -20,12 +21,14 @@ public class Book {
 
     @Column(nullable = false)
     private String title;
-
+    
+    private String isbn;
+    
     @ManyToOne
     @JoinColumn(name = "library_id")
     private Library library;
 
-    @ManyToMany(mappedBy = "books")
+    @ManyToMany(mappedBy = "books", fetch = FetchType.EAGER)
     private List<Author> authors;
 
     public Book() {
@@ -52,6 +55,15 @@ public class Book {
         this.id = id;
     }
 
+    public String getIsbn() {
+        return isbn;
+    }
+
+    public void setIsbn(String isbn) {
+        this.isbn = isbn;
+    }
+
+
     public Library getLibrary() {
         return library;
     }

spring-data-rest/src/main/java/com/baeldung/projections/CustomBook.java

@@ -0,0 +1,22 @@
+package com.baeldung.projections;
+
+import java.util.List;
+
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.data.rest.core.config.Projection;
+
+import com.baeldung.models.Author;
+import com.baeldung.models.Book;
+
+@Projection(name = "customBook", types = { Book.class }) 
+public interface CustomBook {
+    @Value("#{target.id}")
+    long getId(); 
+    
+    String getTitle();
+    
+    List<Author> getAuthors();
+    
+    @Value("#{target.getAuthors().size()}")
+    int getAuthorCount();
+}

spring-data-rest/src/main/java/com/baeldung/repositories/BookRepository.java

@@ -1,9 +1,10 @@
 package com.baeldung.repositories;
 
 import org.springframework.data.repository.CrudRepository;
+import org.springframework.data.rest.core.annotation.RepositoryRestResource;
 
 import com.baeldung.models.Book;
+import com.baeldung.projections.CustomBook;
 
-public interface BookRepository extends CrudRepository<Book, Long> {
-
-}
+@RepositoryRestResource(excerptProjection = CustomBook.class)
+public interface BookRepository extends CrudRepository<Book, Long> {}