Spring Boot创建Maven依赖并引用时编译报错的问题排查

尝试创建一个可供其他Spring Boot项目引用的Maven依赖，common项目构建成功，但sso项目引用该依赖后编译失败，报错信息如下：

[INFO] [1m--- [0;32mcompiler:3.13.0:compile[m [1m(default-compile)[m @ [36msso[0;1m ---[m
[INFO] Recompiling the module because of [1mchanged source code[m.
[INFO] Compiling 3 source files with javac [debug parameters release 21] to target\classes
[INFO] -------------------------------------------------------------
[ERROR] COMPILATION ERROR : 
[INFO] -------------------------------------------------------------
[ERROR] /D:/workspaces/test/sso/src/main/java/ir/com/sso/domain/entity/User.java:[3,35] package ir.com.common.domain.entity does not exist
[ERROR] /D:/workspaces/test/sso/src/main/java/ir/com/sso/domain/entity/User.java:[20,27] cannot find symbol
  symbol: class BaseEntity
[INFO] 2 errors 
[INFO] -------------------------------------------------------------
[INFO] [1m------------------------------------------------------------------------[m
[INFO] [1;31mBUILD FAILURE[m
[INFO] [1m------------------------------------------------------------------------[m
[INFO] Total time:  5.267 s
[INFO] Finished at: 2024-12-06T10:06:06+03:30
[INFO] [1m------------------------------------------------------------------------[m
[ERROR] Failed to execute goal [32morg.apache.maven.plugins:maven-compiler-plugin:3.13.0:compile[m [1m(default-compile)[m on project [36msso[m: [1;31mCompilation failure[m: Compilation failure: 
[ERROR] /D:/workspaces/test/sso/src/main/java/ir/com/sso/domain/entity/User.java:[3,35] package ir.com.common.domain.entity does not exist
[ERROR] /D:/workspaces/test/sso/src/main/java/ir/com/sso/domain/entity/User.java:[20,27] cannot find symbol
[ERROR]   symbol: class BaseEntity
[ERROR] -> [1m[Help 1][m
[ERROR] 
[ERROR] To see the full stack trace of the errors, re-run Maven with the [1m-e[m switch.
[ERROR] Re-run Maven using the [1m-X[m switch to enable full debug logging.
[ERROR] 
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [1m[Help 1][m http://cwiki.apache.org/confluence/display/MAVEN/MojoFailureException

common项目pom.xml配置：

<?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>3.4.0</version>
        <relativePath /> <!-- lookup parent from repository -->
    </parent>
    
    <groupId>ir.com</groupId>
    <artifactId>common</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>common</name>
    <packaging>pom</packaging>
    <description>common project for extend</description>
    
    <properties>
        <java.version>21</java.version>
    </properties>
    
    <dependencies>...</dependencies>

    <build>
        <plugins>

            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <excludes>
                        <exclude>
                            <groupId>org.projectlombok</groupId>
                            <artifactId>lombok</artifactId>
                        </exclude>
                    </excludes>
                </configuration>
            </plugin>

        </plugins>
    </build>

</project>

sso项目pom.xml配置：

<?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>3.4.0</version>        
        <relativePath /> <!-- lookup parent from repository -->
    </parent>

    <groupId>ir.com</groupId>
    <artifactId>sso</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>sso</name>
    <description>Demo project for SSO</description>

    <properties>
        <java.version>21</java.version>
    </properties>

    <dependencies>

        <dependency>
            <groupId>ir.com</groupId>
            <artifactId>common</artifactId>
            <version>0.0.1-SNAPSHOT</version>
            <type>pom</type>
        </dependency>
    ...
    
</project>

1. 修改common项目的打包类型 #

将common项目pom.xml中的<packaging>pom</packaging>改为<packaging>jar</packaging>。pom打包适用于聚合项目或父项目，不会编译生成包含类文件的jar包；jar打包才会编译代码并生成可供其他项目引用的jar。

2. 修改sso项目的依赖配置 #

移除sso依赖中的<type>pom</type>，默认依赖类型即为jar，指定pom类型只会引入common的依赖配置，无法获取其中的Java类。修改后的依赖配置如下：

<dependency>
    <groupId>ir.com</groupId>
    <artifactId>common</artifactId>
    <version>0.0.1-SNAPSHOT</version>
</dependency>

3. 重新构建并安装common项目 #

在common项目根目录执行命令：

mvn clean install

该命令会编译代码、生成jar包并安装到本地Maven仓库，确保sso项目能找到该依赖。

4. 构建sso项目 #

在sso项目根目录执行命令：

mvn clean compile

此时项目应能正常编译，不再出现找不到包和类的错误。

内容的提问来源于stack exchange，提问作者Albert