one-to-many

hibernate-one-to-many/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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+	<parent>
+		<groupId>org.springframework.boot</groupId>
+		<artifactId>spring-boot-starter-parent</artifactId>
+		<version>2.3.3.RELEASE</version>
+		<relativePath/>
+	</parent>
+	<groupId>ru.sysout</groupId>
+	<artifactId>one-to-many</artifactId>
+	<version>0.0.1-SNAPSHOT</version>
+	<name>one-to-many</name>
+	<description>Demo project for Spring Boot</description>
+
+	<properties>
+		<java.version>11</java.version>
+	</properties>
+
+	<dependencies>
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-data-jpa</artifactId>
+		</dependency>
+		<dependency>
+			<groupId>com.h2database</groupId>
+			<artifactId>h2</artifactId>
+			<scope>runtime</scope>
+		</dependency>
+		<dependency>
+			<groupId>org.projectlombok</groupId>
+			<artifactId>lombok</artifactId>
+			<optional>true</optional>
+		</dependency>
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-web</artifactId>
+		</dependency>
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-test</artifactId>
+			<scope>test</scope>
+			<exclusions>
+				<exclusion>
+					<groupId>org.junit.vintage</groupId>
+					<artifactId>junit-vintage-engine</artifactId>
+				</exclusion>
+			</exclusions>
+		</dependency>
+	</dependencies>
+
+	<build>
+		<plugins>
+			<plugin>
+				<groupId>org.springframework.boot</groupId>
+				<artifactId>spring-boot-maven-plugin</artifactId>
+			</plugin>
+		</plugins>
+	</build>
+
+</project>

hibernate-one-to-many/src/main/java/ru/sysout/SpringDataJpaApplication.java

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+package ru.sysout;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.CommandLineRunner;
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.transaction.annotation.Transactional;
+import ru.sysout.bad.dao.TopicRepository;
+import ru.sysout.bad.model.Topic;
+
+import java.util.Optional;
+
+@SpringBootApplication
+public class SpringDataJpaApplication implements CommandLineRunner {
+    @Autowired
+    private TopicRepository topicRepository;
+    public static void main(String[] args) {
+        SpringApplication.run(SpringDataJpaApplication.class, args);
+    }
+
+    @Override
+    public void run(String... args) throws Exception {
+
+     // delComment();
+    }
+    @Transactional
+    public void delComment(){
+        Optional<Topic> optionalTopic = topicRepository.findById(-1l);
+        optionalTopic.get().getComments().remove(0);
+        topicRepository.save(optionalTopic.get());
+    }
+}

hibernate-one-to-many/src/main/java/ru/sysout/bad/dao/CommentRepository.java

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+package ru.sysout.bad.dao;
+
+import org.springframework.data.jpa.repository.JpaRepository;
+import ru.sysout.bad.model.Comment;
+
+public interface CommentRepository extends JpaRepository<Comment, Long> {
+
+}

hibernate-one-to-many/src/main/java/ru/sysout/bad/dao/TopicRepository.java

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+package ru.sysout.bad.dao;
+
+import org.springframework.data.jpa.repository.JpaRepository;
+import ru.sysout.bad.model.Topic;
+
+public interface TopicRepository extends JpaRepository<Topic, Long> {
+}

hibernate-one-to-many/src/main/java/ru/sysout/bad/model/Comment.java

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+package ru.sysout.bad.model;
+
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+import javax.persistence.Entity;
+import javax.persistence.GeneratedValue;
+import javax.persistence.GenerationType;
+import javax.persistence.Id;
+
+@NoArgsConstructor
+@Data
+@Entity
+public class Comment {
+    @Id
+    @GeneratedValue(strategy = GenerationType.SEQUENCE)
+    private long id;
+    private String text;
+
+    public Comment(String text) {
+        this.text = text;
+    }
+
+}

hibernate-one-to-many/src/main/java/ru/sysout/bad/model/Topic.java

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+package ru.sysout.bad.model;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+import javax.persistence.*;
+import java.util.ArrayList;
+import java.util.List;
+
+@Data
+@NoArgsConstructor
+@Entity
+public class Topic {
+    @Id
+    @GeneratedValue(strategy = GenerationType.SEQUENCE)
+    private long id;
+    private String title;
+    @OneToMany(cascade = CascadeType.ALL, orphanRemoval = true)
+    @JoinColumn(name = "topic_id")
+    private List<Comment> comments=new ArrayList<>();
+    public Topic(String title){
+        this.title=title;
+    }
+
+}

hibernate-one-to-many/src/main/java/ru/sysout/good/dao/GoodCommentRepository.java

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+package ru.sysout.good.dao;
+
+import org.springframework.data.jpa.repository.JpaRepository;
+import ru.sysout.good.model.GoodComment;
+
+public interface GoodCommentRepository extends JpaRepository<GoodComment, Long> {
+
+}

hibernate-one-to-many/src/main/java/ru/sysout/good/dao/GoodTopicRepository.java

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+package ru.sysout.good.dao;
+
+import org.springframework.data.jpa.repository.JpaRepository;
+import ru.sysout.good.model.GoodTopic;
+
+public interface GoodTopicRepository extends JpaRepository<GoodTopic, Long> {
+}

hibernate-one-to-many/src/main/java/ru/sysout/good/model/GoodComment.java

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+package ru.sysout.good.model;
+
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+import javax.persistence.*;
+
+@NoArgsConstructor
+@Data
+@Entity
+public class GoodComment {
+    @Id
+    @GeneratedValue(strategy = GenerationType.SEQUENCE)
+    private long id;
+    private String text;
+
+    @ManyToOne(fetch = FetchType.LAZY)
+    private GoodTopic topic;
+
+    public GoodComment(String text) {
+        this.text = text;
+    }
+
+}

hibernate-one-to-many/src/main/java/ru/sysout/good/model/GoodTopic.java

@@ -0,0 +1,31 @@
+package ru.sysout.good.model;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+import javax.persistence.*;
+import java.util.ArrayList;
+import java.util.List;
+
+@Data
+@NoArgsConstructor
+@Entity
+public class GoodTopic {
+    @Id
+    @GeneratedValue(strategy = GenerationType.SEQUENCE)
+    private long id;
+    private String title;
+    @OneToMany(mappedBy = "topic", cascade = CascadeType.ALL, orphanRemoval = true)
+    private List<GoodComment> comments=new ArrayList<>();
+    public GoodTopic(String title){
+        this.title=title;
+    }
+    public void addComment(GoodComment comment) {
+        comments.add(comment);
+        comment.setTopic(this);
+    }
+
+    public void removeComment(GoodComment comment) {
+        comments.remove(comment);
+        comment.setTopic(null);
+    }
+}

hibernate-one-to-many/src/main/resources/application.yml

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+spring:
+  h2:
+    console:
+      enabled: true
+      path: /h2-console
+  datasource:
+     url: jdbc:h2:mem:testdb
+     username: sa
+     password:
+     initialization-mode: always
+  jpa:
+    show-sql: true
+    hibernate:
+      ddl-auto: create

hibernate-one-to-many/src/main/resources/data.sql

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+insert into topic (id, title) values (-1,'title1');
+insert into topic (id, title) values (-2, 'title2');
+insert into topic (id, title) values (-3, 'title3');
+
+insert into comment (id, text, topic_id) values (-4, 'text1', -1);
+insert into comment (id, text, topic_id) values (-5, 'text2', -1);
+insert into comment (id, text, topic_id) values (-6, 'text3', -1);
+
+
+insert into good_topic (id, title) values (-11,'title1');
+insert into good_topic (id, title) values (-12, 'title2');
+insert into good_topic (id, title) values (-13, 'title3');
+
+insert into good_comment (id, text, topic_id) values (-14, 'text1', -11);
+insert into good_comment (id, text, topic_id) values (-15, 'text2', -11);
+insert into good_comment (id, text, topic_id) values (-16, 'text3', -11);

hibernate-one-to-many/src/test/java/ru/sysout/BadStructureTest.java

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+package ru.sysout;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.autoconfigure.orm.jpa.DataJpaTest;
+import ru.sysout.bad.dao.CommentRepository;
+import ru.sysout.bad.dao.TopicRepository;
+import ru.sysout.bad.model.Comment;
+import ru.sysout.bad.model.Topic;
+
+@DataJpaTest
+public class BadStructureTest {
+    @Autowired
+    private TopicRepository topicRepository;
+    @Autowired
+    private CommentRepository commentRepository;
+
+    @Test
+    @DisplayName("при добавлении топика для каждого комментария выполняется insert и update")
+    public void whenAddTopicWithComments_thenInsertsWithUpdates() {
+        Topic topic = new Topic("title");
+        topic.getComments().add(new Comment("c1"));
+        topic.getComments().add(new Comment("c2"));
+        topic.getComments().add(new Comment("c3"));
+        topic = topicRepository.save(topic);
+
+        Assertions.assertEquals(4, topicRepository.count());
+    }
+
+    @Test
+    @DisplayName("при удалении комментария для него выполняется update и delete")
+
+    public void whenDeleteComment_thenDeleteWithUpdate() {
+       Topic topic = topicRepository.getOne(-1l);
+       topic.getComments().remove(0);
+
+       Assertions.assertEquals(2, commentRepository.count());
+    }
+}

hibernate-one-to-many/src/test/java/ru/sysout/GoodStructureTest.java

@@ -0,0 +1,41 @@
+package ru.sysout;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.autoconfigure.orm.jpa.DataJpaTest;
+import ru.sysout.good.dao.GoodCommentRepository;
+import ru.sysout.good.dao.GoodTopicRepository;
+import ru.sysout.good.model.GoodComment;
+import ru.sysout.good.model.GoodTopic;
+
+@DataJpaTest
+public class GoodStructureTest {
+    @Autowired
+    private GoodTopicRepository topicRepository;
+    @Autowired
+    private GoodCommentRepository commentRepository;
+
+    @Test
+    @DisplayName("при добавлении топика для каждого комментария выполняется один insert")
+    public void whenAddTopicWithComments_thenInsertsWithUpdates() {
+        GoodTopic topic = new GoodTopic("title");
+        topic.addComment(new GoodComment("c1"));
+        topic.addComment(new GoodComment("c2"));
+        topic.addComment(new GoodComment("c3"));
+        topic = topicRepository.save(topic);
+
+        Assertions.assertEquals(4, topicRepository.count());
+    }
+
+    @Test
+    @DisplayName("при удалении комментария для него выполняется один delete")
+
+    public void whenDeleteComment_thenDeleteWithUpdate() {
+       GoodTopic topic = topicRepository.getOne(-11l);
+       topic.getComments().remove(0);
+
+       Assertions.assertEquals(2, commentRepository.count());
+    }
+}