Java 11 没有模块化：包在添加为 Maven 依赖项时不存在

Question

我有三个非常简单的应用程序。一个是 COMMON，我将以安全配置为中心，另一个具有 ZUUL 功能，第三个是 EUREKA SERVER。两者都是 Spring Boot 和 Java 11。虽然我使用的是 Java 11，但我并不依赖模块化（据我所知，使用 [=52 的模块化功能没有意义=]开机）。

当我运行 Eclipse 中的所有三个时，我可以成功地运行服务器、common 和 zuul 按顺序排列。当我尝试构建 Maven 时，出现主题中提到的错误。

直接的解释是"you don't have common in zuul classpath"。好吧，据我所知，我在 zuul classpath 中确实有共同点。我想知道是否有任何额外的配置，因为我正在使用 Java 11 但没有使用模块化。

说我使用的是 Java 11 但不是模块化我的意思是，我有 Java 11 但我在这三个中的任何一个中都没有模块-info.java项目。

检查 .m2 文件夹并解压缩 common.jar 我确实看到了 class 投诉。

Zuul 项目 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/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.3.RELEASE</version>
        <relativePath /> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.test</groupId>
    <artifactId>zuul</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>zuul</name>
    <description>Zuul project</description>

    <properties>
        <java.version>11</java.version>
        <spring-cloud.version>Greenwich.SR1</spring-cloud.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-zuul</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-security</artifactId>
        </dependency>
        <!-- https://mvnrepository.com/artifact/io.jsonwebtoken/jjwt -->
        <dependency>
            <groupId>io.jsonwebtoken</groupId>
            <artifactId>jjwt</artifactId>
            <version>0.9.1</version>
        </dependency>

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

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>${spring-cloud.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

证据表明常见的是 Maven 依赖性

mvn 全新安装期间出错：

[INFO] Scanning for projects...
[INFO] 
[INFO] ---------------------------< com.test:zuul >----------------------------
[INFO] Building zuul 0.0.1-SNAPSHOT
[INFO] --------------------------------[ jar ]---------------------------------
[INFO] 
[INFO] --- maven-resources-plugin:3.1.0:resources (default-resources) @ zuul ---
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] Copying 1 resource
[INFO] Copying 0 resource
[INFO] 
[INFO] --- maven-compiler-plugin:3.8.0:compile (default-compile) @ zuul ---
[INFO] Changes detected - recompiling the module!
[INFO] Compiling 2 source files to C:\_d\WSs\soteste\zuul\target\classes
[INFO] -------------------------------------------------------------
[ERROR] COMPILATION ERROR : 
[INFO] -------------------------------------------------------------
[ERROR] /C:/_d/WSs/soteste/zuul/src/main/java/com/test/zuul/security/SecurityTokenConfig.java:[14,32] package com.test.common.security does not exist
[ERROR] /C:/_d/WSs/soteste/zuul/src/main/java/com/test/zuul/security/SecurityTokenConfig.java:[21,17] cannot find symbol
  symbol:   class JwtConfig
  location: class com.test.zuul.security.SecurityTokenConfig
[ERROR] /C:/_d/WSs/soteste/zuul/src/main/java/com/test/zuul/security/SecurityTokenConfig.java:[46,16] cannot find symbol
  symbol:   class JwtConfig
  location: class com.test.zuul.security.SecurityTokenConfig
[ERROR] /C:/_d/WSs/soteste/zuul/src/main/java/com/test/zuul/security/SecurityTokenConfig.java:[47,23] cannot find symbol
  symbol:   class JwtConfig
  location: class com.test.zuul.security.SecurityTokenConfig
[INFO] 4 errors 
[INFO] -------------------------------------------------------------
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 4.778 s
[INFO] Finished at: 2019-03-21T14:23:23-03:00
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.8.0:compile (default-compile) on project zuul: Compilation failure: Compilation failure: 
[ERROR] /C:/_d/WSs/soteste/zuul/src/main/java/com/test/zuul/security/SecurityTokenConfig.java:[14,32] package com.test.common.security does not exist
[ERROR] /C:/_d/WSs/soteste/zuul/src/main/java/com/test/zuul/security/SecurityTokenConfig.java:[21,17] cannot find symbol
[ERROR]   symbol:   class JwtConfig
[ERROR]   location: class com.test.zuul.security.SecurityTokenConfig
[ERROR] /C:/_d/WSs/soteste/zuul/src/main/java/com/test/zuul/security/SecurityTokenConfig.java:[46,16] cannot find symbol
[ERROR]   symbol:   class JwtConfig
[ERROR]   location: class com.test.zuul.security.SecurityTokenConfig
[ERROR] /C:/_d/WSs/soteste/zuul/src/main/java/com/test/zuul/security/SecurityTokenConfig.java:[47,23] cannot find symbol
[ERROR]   symbol:   class JwtConfig
[ERROR]   location: class com.test.zuul.security.SecurityTokenConfig
[ERROR] -> [Help 1]
[ERROR] 
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR] 
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoFailureException

抱怨的class在罐子里

*** 已编辑

普通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/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.3.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.test</groupId>
    <artifactId>common</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>common</name>
    <description>Zuul project</description>

    <properties>
        <java.version>11</java.version>
        <spring-cloud.version>Greenwich.SR1</spring-cloud.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</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-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>${spring-cloud.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

Answer 1

Eclipse能够将当前打开的工作空间的Eclipse项目作为Maven依赖解析到其他项目中，这是Eclipse的特长。

如果您在命令行上或从 Eclipse 中执行 Maven，您将离开 Eclipse 的领域并使用普通的 Maven。 Plain Maven（甚至是 Eclipse 中集成的 Maven）不知道 Eclipse 项目，它只知道本地和配置的远程存储库中可用的工件。

因此，在您的情况下，正确的方法是首先在您的 common 项目上执行 mvn install。这会将 common 安装到您的本地存储库中，并使其可供 Maven 使用。

之后您可以在 zuul 项目上执行 mvn clean install。

Answer 2

那是因为 common 项目是一个 Spring 引导应用程序（我在生成的 jar 中看到了 BOOT-INF 文件夹）。

来自 Use a Spring Boot Application as a Dependency 文档：

The executable archive cannot be used as a dependency as the executable jar format packages application classes in BOOT-INF/classes. This means that they cannot be found when the executable jar is used as a dependency.

To produce the two artifacts, one that can be used as a dependency and one that is executable, a classifier must be specified. This classifier is applied to the name of the executable archive, leaving the default archive for use as a dependency.

<build>
    <plugins>
        <plugin>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-maven-plugin</artifactId>
            <configuration>
                <classifier>exec</classifier>
            </configuration>
        </plugin>
    </plugins>
</build>

这是一个例子：

第一个 jar 构建为可依赖的，第二个是 Spring 引导可执行文件。

Java 11 没有模块化：包在添加为 Maven 依赖项时不存在

Java 11 without modularity: package does not exist while it is added as maven dependency

java

eclipse

maven

spring-boot

java-11