【发布时间】：2021-04-01 12:23:06
【问题描述】：
我想在我的 Java 应用程序中使用 Clojure 代码：
; clj.clj
(ns utils
(:gen-class
:name clj.Clj
:methods [#^{:static true} [clj [] String]])
(defn -clj []
"Hello from Clojure!")
// Java.java
package main;
import clj.Clj;
public class Java {
public static void main(String[] args) {
System.out.println("Java main");
System.out.println(Clj.clj());
}
}
当我运行 JAR 文件时，我想要输出：
Java main
Hello from Clojure!
如何编译 Clojure 和 Java 文件并使用 Maven 将它们打包成可运行的 JAR 文件？
更新：
这是我拥有的当前代码：
<!-- 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.github.loadingbg</groupId>
<artifactId>proj</artifactId>
<version>1.0.0</version>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>
<build>
<plugins>
<!-- Clojure Compiler -->
<plugin>
<groupId>com.theoryinpractise</groupId>
<artifactId>clojure-maven-plugin</artifactId>
<version>1.8.4</version>
<executions>
<execution>
<phase>compile</phase>
<goals>
<goal>compile</goal>
</goals>
</execution>
</executions>
<configuration>
<namespaces>
<namespace>utils</namespace>
</namespaces>
<compileDeclaredNamespaceOnly>true</compileDeclaredNamespaceOnly>
<sourceDirectories>
<sourceDirectory>src/main/clojure</sourceDirectory>
</sourceDirectories>
</configuration>
</plugin>
<!-- Maven Compiler -->
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.8.1</version>
<configuration>
<source>11</source>
<target>11</target>
</configuration>
</plugin>
<!-- Maven Assembly Plugin -->
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-assembly-plugin</artifactId>
<version>3.3.0</version>
<executions>
<execution>
<phase>package</phase>
<goals>
<goal>single</goal>
</goals>
</execution>
</executions>
<configuration>
<archive>
<manifest>
<addClasspath>true</addClasspath>
<mainClass>proj.Main</mainClass>
</manifest>
</archive>
<descriptorRefs>
<descriptorRef>jar-with-dependencies</descriptorRef>
</descriptorRefs>
</configuration>
</plugin>
<!-- Maven Shade Plugin -->
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-shade-plugin</artifactId>
<version>3.2.4</version>
<executions>
<execution>
<phase>package</phase>
<goals>
<goal>shade</goal>
</goals>
</execution>
</executions>
<configuration>
<minimizeJar>true</minimizeJar>
<transformers>
<transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
<mainClass>proj.Main</mainClass>
</transformer>
</transformers>
</configuration>
</plugin>
</plugins>
</build>
<dependencies>
<dependency>
<groupId>org.clojure</groupId>
<artifactId>clojure</artifactId>
<version>1.10.0</version>
</dependency>
</dependencies>
</project>
; /src/main/clojure/utils.clj
(ns utils
(:gen-class
:name utils.Utils
:methods [#^{:static true} [clj [] String]]))
(defn -clj []
"Hello from clojure")
// /src/main/java/pack/Main.java
package proj;
import utils.Utils;
public class Main {
public static void main(String[] args) {
System.out.println("Starting");
System.out.println(Utils.clj());
}
}
我在运行mvn clean install 时得到以下信息：
WARNING: An illegal reflective access operation has occurred
WARNING: Illegal reflective access by com.google.inject.internal.cglib.core.$ReflectUtils$1 (file:/usr/share/maven/lib/guice.jar) to method java.lang.ClassLoader.defineClass(java.lang.String,byte[],int,int,java.security.ProtectionDomain)
WARNING: Please consider reporting this to the maintainers of com.google.inject.internal.cglib.core.$ReflectUtils$1
WARNING: Use --illegal-access=warn to enable warnings of further illegal reflective access operations
WARNING: All illegal access operations will be denied in a future release
[INFO] Scanning for projects...
[INFO]
[INFO] ----------------------< com.github.loadingbg:bot >----------------------
[INFO] Building bot 1.0.0
[INFO] --------------------------------[ jar ]---------------------------------
[INFO]
[INFO] --- maven-clean-plugin:2.5:clean (default-clean) @ bot ---
[INFO] Deleting /home/loadingbg/proj/target
[INFO]
[INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ bot ---
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] skip non existing resourceDirectory /home/loadingbg/proj/src/main/resources
[INFO]
[INFO] --- maven-compiler-plugin:3.8.1:compile (default-compile) @ bot ---
[INFO] Changes detected - recompiling the module!
[INFO] Compiling 1 source file to /home/loadingbg/proj/target/classes
[INFO] -------------------------------------------------------------
[ERROR] COMPILATION ERROR :
[INFO] -------------------------------------------------------------
[ERROR] /home/loadingbg/proj/src/main/java/proj/Main.java:[3,13] package utils does not exist
[ERROR] /home/loadingbg/proj/src/main/java/proj/Main.java:[8,28] cannot find symbol
symbol: variable Utils
location: class proj.Main
[INFO] 2 errors
[INFO] -------------------------------------------------------------
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 1.136 s
[INFO] Finished at: 2020-12-22T22:36:42+02:00
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.8.1:compile (default-compile) on project
bot: Compilation failure: Compilation failure:
[ERROR] /home/loadingbg/proj/src/main/java/proj/Main.java:[3,13] package utils does not exist
[ERROR] /home/loadingbg/proj/src/main/java/proj/Main.java:[8,28] cannot find symbol
[ERROR] symbol: variable Utils
[ERROR] location: class proj.Main
[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
它只是拒绝承认从 Clojure 文件生成的类。 utils.clj 应该生成具有静态方法 Utils#clj() 的 utils.Utils 类，该方法返回一个字符串。
我看到将clojure-maven-plugin 移动到maven-compiler-plugin 上方会有所帮助，但没有。关键是让clojure-maven-plugin 在maven-compiler-plugin 之前执行，但事实并非如此。如何重新排序插件执行顺序，这会有所帮助吗？
更新 2（回应 Alan Thompson）：
我在新的 Leiningen 项目中复制了之前的代码，但出现此错误：
Compiling 1 source files to /home/loadingbg/proj/target/default/class-files
/home/loadingbg/proj/src/java/proj/Main.java:3: error: package utils does not exist
import utils.Utils;
^
/home/loadingbg/proj/src/java/proj/Main.java:8: error: cannot find symbol
System.out.println(Utils.clj());
^
symbol: variable Utils
location: class Main
2 errors
Compilation of Java sources(lein javac) failed.
我错过了什么吗？我复制了project.clj。
【问题讨论】：
标签： java maven clojure clojure-java-interop