spring-boot - 带有数据 JPA 的 Spring Boot 多模块不起作用

Question

我有我的多模块 Spring 启动项目。我将服务、实体和存储库移至核心模块，而在 war 模块中，我只有 Controller 。

这里有什么问题？如果我在没有 JPA 的情况下使用，那么我的核心模块工作正常。如果我在核心模块中添加 JPA 依赖项并在我的服务中注入(inject)存储库，那么我会收到各种错误，例如存储库的 noclassdefinitionfound、没有 Service 类型的合格 bean 等。

如何使这个应用程序工作？

父 pom.xml

<?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/maven-v4_0_0.xsd">

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.2.RELEASE</version>
        <relativePath /> <!-- lookup parent from repository -->
    </parent>

    <name>appx</name>
    <modelVersion>4.0.0</modelVersion>
    <groupId>org.imsx</groupId>
    <artifactId>appx</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>pom</packaging>

    <modules>
        <module>core</module>
        <module>webx</module>
        <module>imsx</module>
    </modules>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <version.wildfly.maven.plugin>1.0.2.Final</version.wildfly.maven.plugin>
        <version.jboss.bom>8.2.1.Final</version.jboss.bom>
        <version.wildfly>14.0.1.Final</version.wildfly>
        <version.compiler.plugin>3.8.0</version.compiler.plugin>
        <version.ear.plugin>3.0.1</version.ear.plugin>
        <version.jar.plugin>3.1.1</version.jar.plugin>
        <version.war.plugin>3.2.2</version.war.plugin>

        <maven.compiler.target>1.8</maven.compiler.target>
        <maven.compiler.source>1.8</maven.compiler.source>
    </properties>

    <build>
        <pluginManagement>
            <plugins>
                <plugin>
                    <artifactId>maven-compiler-plugin</artifactId>
                    <configuration>
                        <source>${maven.compiler.source}</source>
                        <target>${maven.compiler.target}</target>
                    </configuration>
                    <version>${version.compiler.plugin}</version>
                </plugin>
                <plugin>
                    <groupId>org.wildfly.plugins</groupId>
                    <artifactId>wildfly-maven-plugin</artifactId>
                    <version>${version.wildfly.maven.plugin}</version>
                    <inherited>true</inherited>
                    <configuration>
                        <skip>true</skip>
                    </configuration>
                </plugin>
            </plugins>
        </pluginManagement>
    </build>
</project>

下面是我的 Ear 模块 pom。

<?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/maven-v4_0_0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <parent>
        <artifactId>appx</artifactId>
        <groupId>org.imsx</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>

    <artifactId>imsx</artifactId>
    <packaging>ear</packaging>

    <name>appx: EAR Module</name>

    <dependencies>
        <dependency>
            <groupId>org.imsx</groupId>
            <artifactId>webx</artifactId>
            <version>${project.version}</version>
            <type>war</type>
        </dependency>
    </dependencies>

    <build>
        <finalName>${project.artifactId}</finalName>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-ear-plugin</artifactId>
                <version>${version.ear.plugin}</version>
                <configuration>
                    <version>7</version>
                    <defaultLibBundleDir>lib</defaultLibBundleDir>
                    <modules>
                        <webModule>
                            <groupId>org.imsx</groupId>
                            <artifactId>webx</artifactId>
                            <contextRoot>/imsx</contextRoot>
                            <bundleFileName>webx.war</bundleFileName>
                        </webModule>
                    </modules>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.wildfly.plugins</groupId>
                <artifactId>wildfly-maven-plugin</artifactId>
                <configuration>
                    <filename>${project.artifactId}.ear</filename>
                    <skip>false</skip>
                </configuration>
            </plugin>
        </plugins>
    </build>

</project>

这是我的核心模块 pom 与 JPA 和 mysql 依赖项。

<?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/maven-v4_0_0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <parent>
        <artifactId>appx</artifactId>
        <groupId>org.imsx</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>

    <artifactId>core</artifactId>
    <packaging>jar</packaging>
    <name>appx: Core Module</name>

    <dependencies>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
            <exclusions>
                <exclusion>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-starter-tomcat</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
            <scope>provided</scope> <!-- I tried by removing this provided scope as well and got different error in repository level like datasource is not found -->
            <exclusions>
                <exclusion>
                    <groupId>org.apache.tomcat</groupId>
                    <artifactId>tomcat-jdbc</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>

    </dependencies>

    <build>
        <finalName>${project.artifactId}</finalName>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <skip>true</skip>
                </configuration>
            </plugin>
            <plugin>
                <artifactId>maven-jar-plugin</artifactId>
                <version>${version.jar.plugin}</version><!--$NO-MVN-MAN-VER$ -->
            </plugin>
        </plugins>
    </build>

</project>

最后我有了我的 war 模块 pom。我在其中包含了核心模块。

<?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/maven-v4_0_0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <parent>
        <artifactId>appx</artifactId>
        <groupId>org.imsx</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>

    <artifactId>webx</artifactId>
    <packaging>war</packaging>

    <name>appx: WAR Module</name>

    <url>http://wildfly.org</url>
    <licenses>
        <license>
            <name>Apache License, Version 2.0</name>
            <distribution>repo</distribution>
            <url>http://www.apache.org/licenses/LICENSE-2.0.html</url>
        </license>
    </licenses>

    <dependencies>

        <dependency>
            <groupId>org.imsx</groupId>
            <artifactId>core</artifactId>
            <version>${project.version}</version>
            <type>jar</type>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
            <exclusions>
                <exclusion>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-starter-tomcat</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
    </dependencies>

    <build>
        <finalName>${project.artifactId}</finalName>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
            <plugin>
                <artifactId>maven-war-plugin</artifactId>
                <configuration>
                    <failOnMissingWebXml>false</failOnMissingWebXml>
                </configuration>
            </plugin>
        </plugins>
    </build>

</project>

我在核心模块中有 application.properties，我在其中指定了我的数据库连接。

## Spring DATASOURCE (DataSourceAutoConfiguration & DataSourceProperties)
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
spring.datasource.url = jdbc:mysql://localhost:3306/bootear?autoReconnect=true&useUnicode=true&characterEncoding=UTF-8&allowMultiQueries=true&useSSL=false
spring.datasource.username = root
spring.datasource.password = root
spring.jpa.properties.hibernate.dialect = org.hibernate.dialect.MySQL5InnoDBDialect
spring.jpa.hibernate.ddl-auto = update

我在 war 模块的属性文件中没有任何内容。

这是我的Java代码:

@RestController
public class UserController {

    @Autowired
    private UserService userService;

    @RequestMapping(value="/test", method=RequestMethod.GET)
    public String test() {
        Optional<User> user = userService.findUserById(1);
        System.out.println(user.isPresent());
        return "Search Completed...";
    }
}


public interface UserService {
    Optional<User> findUserById(Integer id);
}


@Service
@Transactional
public class UserServiceImpl implements UserService {

    @Autowired
    private UserRepository userRepository;

    @Override
    public Optional<User> findUserById(Integer id) {
        return userRepository.findById(id);
    }
}

@Repository
public interface UserRepository extends JpaRepository<User, Integer> {

}

如果我在一个单一的 war 模块中拥有所有这些代码，那么它工作正常。这里有什么问题？

我正在将这个 EAR 部署在 Wildfly 服务器中。它仍然无法正常工作并破坏了我 2 天的时间。

Answer 1

发生这种情况是因为默认情况下 Spring Boot 仅在带有 @EnableAutoConfiguration (或 @SpringBootApplication )注释的类的同一包/子包中查找存储库。

如果要手动指示存储库的位置，请使用 @EnableJpaRepositories 注释并添加适当的 basePackages 值，如下所示:

@SpringBootApplication(scanBasePackages = "com.xyz")
@EnableJpaRepositories(basePackages = "com.xyz")
public class Application {

    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }
}

这样，即使它们在另一个模块中，spring boot 也会找到您的存储库，您只需要遵守包的命名约定。

有关这方面的更多信息，请参见 spring 文档(第 83.3 点):
https://docs.spring.io/spring-boot/docs/current/reference/html/howto-data-access.html