Spring Boot TestEntityManager 教程 · ZetCode 中文系列教程

# Spring Boot `TestEntityManager` 教程 > 原文： [http://zetcode.com/springboot/testentitymanager/](http://zetcode.com/springboot/testentitymanager/) Spring Boot `TestEntityManager`教程展示了如何在 JPA 测试中使用`TestEntityManager`。 `TestEntityManager`提供了`EntityManager`方法的子集，可用于测试以及用于常见测试任务（例如`persist`或`find`）的辅助方法。 Spring 是用于创建企业应用的流行 Java 应用框架。 Spring Boot 是 Spring 框架的演进，可帮助您轻松创建独立的，生产级的基于 Spring 的应用。 ## `TestEntityManager` `TestEntityManager`允许在测试中使用`EntityManager`。 Spring `Repository`是`EntityManager`的抽象；它使开发者免受 JPA 底层细节的困扰，并带来了许多便捷的方法。但是 Spring 允许在应用代码和测试中需要时使用`EntityManager`。在我们的测试中，我们可以从应用中注入`DataSource`，`@JdbcTemplate`，`@EntityManager`或任何 Spring Data 存储库。 ## Spring `TestEntityManager`示例以下应用使用`TestEntityManager`以测试方法保存了一些城市实体。 ```java pom.xml src ├───main │ ├───java │ │ └───com │ │ └───zetcode │ │ │ Application.java │ │ │ MyRunner.java │ │ ├───model │ │ │ City.java │ │ └───repository │ │ CityRepository.java │ └───resources └───test └───java └───com └───zetcode └───repository CityRepositoryTest.java ``` 这是项目结构。 `pom.xml` ```java <?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.zetcode</groupId> <artifactId>springboottestentitymanager</artifactId> <version>1.0-SNAPSHOT</version> <packaging>jar</packaging> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <maven.compiler.source>11</maven.compiler.source> <maven.compiler.target>11</maven.compiler.target> </properties> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>2.1.1.RELEASE</version> </parent> <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-test</artifactId> <scope>test</scope> </dependency> <dependency> <groupId>com.h2database</groupId> <artifactId>h2</artifactId> <scope>runtime</scope> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build> </project> ``` Maven POM 文件包含 Spring Data JPA，测试和 H2 数据库的依赖项。 `com/zetcode/model/City.java` ```java package com.zetcode.model; import java.util.Objects; import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType; import javax.persistence.Id; import javax.persistence.Table; @Entity @Table(name = "cities") public class City { @Id @GeneratedValue(strategy = GenerationType.AUTO) private Long id; private String name; private int population; public City() { } public City(String name, int population) { this.name = name; this.population = population; } public Long getId() { return id; } public void setId(Long id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public int getPopulation() { return population; } public void setPopulation(int population) { this.population = population; } @Override public int hashCode() { int hash = 7; hash = 79 * hash + Objects.hashCode(this.id); hash = 79 * hash + Objects.hashCode(this.name); hash = 79 * hash + this.population; return hash; } @Override public boolean equals(Object obj) { if (this == obj) { return true; } if (obj == null) { return false; } if (getClass() != obj.getClass()) { return false; } final City other = (City) obj; if (this.population != other.population) { return false; } if (!Objects.equals(this.name, other.name)) { return false; } return Objects.equals(this.id, other.id); } @Override public String toString() { var builder = new StringBuilder(); builder.append("City{id=").append(id).append(", name=") .append(name).append(", population=") .append(population).append("}"); return builder.toString(); } } ``` 这是`City`实体。 `com/zetcode/repository/CityRepository.java` ```java package com.zetcode.repository; import com.zetcode.model.City; import org.springframework.data.repository.CrudRepository; import org.springframework.stereotype.Repository; import java.util.List; @Repository public interface CityRepository extends CrudRepository<City, Long> { List<City> findByName(String name); } ``` `CityRepository`包含自定义的`findByName()`方法。 Spring 检查方法的名称，并从其关键字派生查询。 `com/zetcode/MyRunner.java` ```java package com.zetcode; import com.zetcode.model.City; import com.zetcode.repository.CityRepository; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.boot.CommandLineRunner; import org.springframework.stereotype.Component; @Component public class MyRunner implements CommandLineRunner { private static final Logger logger = LoggerFactory.getLogger(MyRunner.class); @Autowired private CityRepository cityRepository; @Override public void run(String... args) throws Exception { logger.info("Saving cities"); cityRepository.save(new City("Bratislava", 432000)); cityRepository.save(new City("Budapest", 1759000)); cityRepository.save(new City("Prague", 1280000)); cityRepository.save(new City("Warsaw", 1748000)); logger.info("Retrieving cities"); var cities = cityRepository.findAll(); cities.forEach(city -> logger.info("{}", city)); } } ``` 在`MyRunner`中，我们使用`CityRepository`保存和检索实体。数据存储在内存中的 H2 数据库中。 > **注意**：在Java企业应用中，定义与存储库一起使用的服务层是一个好习惯。为简单起见，我们跳过服务层。 `com/zetcode/Application.java` ```java package com.zetcode; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; @SpringBootApplication public class Application { public static void main(String[] args) { SpringApplication.run(Application.class, args); } } ``` `Application`设置 Spring Boot 应用。 `@SpringBootApplication`启用自动配置和组件扫描。 `com/zetcode/repository/CityRepositoryTest.java` ```java package com.zetcode.repository; import com.zetcode.model.City; import org.junit.Test; import org.junit.runner.RunWith; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.boot.test.autoconfigure.orm.jpa.DataJpaTest; import org.springframework.boot.test.autoconfigure.orm.jpa.TestEntityManager; import org.springframework.test.context.junit4.SpringRunner; import static org.assertj.core.api.Assertions.assertThat; import static org.junit.Assert.assertEquals; @RunWith(SpringRunner.class) @DataJpaTest public class CityRepositoryTest { @Autowired private TestEntityManager entityManager; @Autowired private CityRepository repository; @Test public void testFindByName() { entityManager.persist(new City("Bratislava", 432000)); entityManager.persist(new City("Budapest", 1759000)); entityManager.persist(new City("Prague", 1280000)); entityManager.persist(new City("Warsaw", 1748000)); var cities = repository.findByName("Bratislava"); assertEquals(1, cities.size()); assertThat(cities).extracting(City::getName).containsOnly("Bratislava"); } } ``` 在`CityRepositoryTest`中，我们测试了自定义 JPA 方法。 ```java @Autowired private TestEntityManager entityManager; ``` 我们注入`TestEntityManager`。 ```java @RunWith(SpringRunner.class) @DataJpaTest public class CityRepositoryTest { ``` `@DataJpaTest`用于测试 JPA 信息库。它与`@RunWith(SpringRunner.class)`结合使用。注解会禁用完全自动配置，并且仅应用与 JPA 测试相关的配置。默认情况下，用`@DataJpaTest`注解的测试使用嵌入式内存数据库。 ```java entityManager.persist(new City("Bratislava", 432000)); entityManager.persist(new City("Budapest", 1759000)); entityManager.persist(new City("Prague", 1280000)); entityManager.persist(new City("Warsaw", 1748000)); ``` 我们用`EntityManager`的`persist()`方法保存了四个城市。 ```java var cities = repository.findByName("Bratislava"); assertEquals(1, cities.size()); ``` 我们测试`findByName()`方法返回一个城市。 ```java assertThat(cities).extracting(City::getName).containsOnly("Bratislava"); ``` 在这里，我们测试城市的名称。 ```java $ mvn spring-boot:test ``` 我们运行测试。在本教程中，我们在测试中使用了`TestEntityManager`。 * [Spring Boot `@DataJpaTest`教程](/springboot/datajpatest/) * [Spring Boot Data JPA `@NamedQuery`教程](/springboot/datajpanamedquery/) * [Spring Boot REST Data JPA 教程](/articles/springbootrestdatajpa/) * [Spring Boot Data JPA 排序教程](/springboot/datajpasort/) * [Spring Boot `CrudRepository`教程](/springboot/crudrepository/) 列出[所有 Spring Boot 教程](/all/#springboot)。