找不到软件包（多模块spring项目）

时间：2019-01-11 11:17:08

标签： java spring maven

我已经使用Spring Initializr创建了两个模块：

api （这是Spring Web）

db （这是Spring Data MongoDB）

我已经将它们放在同一个项目中，以某种方式它们现在是子模块。

在创建测试之前，我可以mvn clean install显示一条BUILD SUCCESS消息。没问题。

但是，如果我尝试创建一个测试（或什至在 main 结构内的控制器中使用它），则该测试将使用 db 模块存储库类来获取来自MongoDB的数据，mvn clean install将指出程序包不存在，尽管IntelliJ可以识别它并对其建立索引，并且文件存在。

结构为：

api
\- src/main/java
  \- com.example.api.controllers
    \- UserController.java
\- src/test/java
  \- com.example.api.controllers
    \- UserControllerTest.java
db
\- src/main/java
  \- com.example.db.repositories
    \- UserRepository.java
model
\- src/main/java
  \- com.example.model
    \- User.java

ApiApplication.java 

package com.example.api;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.web.server.WebServerFactoryCustomizer;
import org.springframework.boot.web.servlet.server.ConfigurableServletWebServerFactory;
import org.springframework.web.servlet.config.annotation.CorsRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

@SpringBootApplication
public class ApiApplication {

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

}

UserController.java 

package com.example.api.controllers;

import com.example.api.Constants;
import com.example.db.repositories.UserRepository;
import com.example.model.User;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class UserController {
    @Autowired
    private UserRepository userRepository;

    @GetMapping(Constants.V1 + "user")
    public User getUser() {
        User user = new User("John");
        userRepository.save(user);
        return user;
    }
}

现在，如果我运行mvn clean install，我将收到提示package com.example.db.repositories does not exist的maven错误。

模块 db 是模块 api 中的依赖项，并且 api 模块设置为在 db 之后父母的绒球。

父级-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/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.example</groupId>
    <artifactId>demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>pom</packaging>

    <modules>
        <module>model</module>
        <module>db</module>
        <module>api</module>
    </modules>

</project>

数据库-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/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.1.RELEASE</version>
        <relativePath/>
    </parent>

    <groupId>com.example</groupId>
    <artifactId>db</artifactId>
    <version>0.0.1-SNAPSHOT</version>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-mongodb</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>com.example</groupId>
            <artifactId>model</artifactId>
            <version>0.0.1-SNAPSHOT</version>
            <scope>compile</scope>
        </dependency>
    </dependencies>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <java.version>1.8</java.version>
    </properties>

</project>

api-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/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>LATEST</version>
        <relativePath/>
    </parent>

    <groupId>com.example</groupId>
    <artifactId>api</artifactId>
    <version>0.0.1-SNAPSHOT</version>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>com.example</groupId>
            <artifactId>db</artifactId>
            <version>0.0.1-SNAPSHOT</version>
        </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>

如何使Maven看到此软件包？

找到包后出现新错误 

2019-01-14 19:16:55.060  WARN 31104 --- [           main] ConfigServletWebServerApplicationContext : Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'userController': Unsatisfied dependency expressed through field 'userRepository'; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'com.example.db.repositories.UserRepository' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
2019-01-14 19:16:55.066  INFO 31104 --- [           main] o.apache.catalina.core.StandardService   : Stopping service [Tomcat]
2019-01-14 19:16:55.087  INFO 31104 --- [           main] ConditionEvaluationReportLoggingListener : 

Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2019-01-14 19:16:55.224 ERROR 31104 --- [           main] o.s.b.d.LoggingFailureAnalysisReporter   : 

***************************
APPLICATION FAILED TO START
***************************

Description:

Field userRepository in com.example.api.controllers.UserController required a bean of type 'com.example.db.repositories.UserRepository' that could not be found.

The injection point has the following annotations:
        - @org.springframework.beans.factory.annotation.Autowired(required=true)


Action:

Consider defining a bean of type 'com.example.db.repositories.UserRepository' in your configuration.

3 个答案:

答案 0 :(得分：2)

Springboot自动发现将仅从您的配置类开始。您的应用程序位于

com.example.api

但仓库位于

com.example.db

也可以添加搜索路径以自动发现.db或将应用程序类移至com.example或将数据库代码移至com.example.api

选项1 

@ComponentScan(“com.example”)
@SpringBootApplication
public class ExampleApplication  {

选项2 

@ComponentScan({"com.example.api","com.example.db"})
@SpringBootApplication
public class ExampleApplication {

您也可以将scanBasePackages属性添加到SpringbootApplication批注中，以达到相同的效果。

@SpringBootApplication(scanBasePackages= {"com.example.api","com.example.db"})
public class ExampleApplication {

在此处查看文档https://docs.spring.io/spring-boot/docs/current/api/org/springframework/boot/autoconfigure/SpringBootApplication.html#scanBasePackages--

答案 1 :(得分：1)

您正在使用db（重新）包装spring-boot-maven-plugin作为Spring Boot“应用程序”而不是库：

<plugin>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-maven-plugin</artifactId>
  <executions>
    <execution>
      <goals>
        <goal>repackage</goal>
      </goals>
    </execution>
  </executions>
</plugin>

将jar进行重新包装，从而在BOOT-INF文件夹中添加com.example.db.repositories软件包（及其类）。这会导致编译失败。

Boot-repackage

只需从<plugin>..</plugin>中除去db/pom.xml部分。这将创建一个常规jar，可以将其导入api模块中。

Jar

注意：我假设api具有Main类，并将打包为启动应用程序。

答案 2 :(得分：0)

实际上，API必须看到DB类。

请确保：

  1. 父项目的包装类型为git add .（pom）
  2. 如果api的依赖性与数据库的版本相同，则版本
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