java - Antlr4 与 Maven 示例项目

Question

我有一个使用 Antlr4.5 的 Maven 项目，其结构如下:

src/main/antlr4/ArrayInit.g4
src/main/java/Test.java
pom.xml

测试.java:

import org.antlr.v4.runtime.*;
import org.antlr.v4.runtime.tree.*;
public class Test {
    public static void main(String[] args) throws Exception {
        ANTLRInputStream input = new ANTLRInputStream(System.in);
        ArrayInitLexer lexer = new ArrayInitLexer(input);
        CommonTokenStream tokens = new CommonTokenStream(lexer);
        ArrayInitParser parser = new ArrayInitParser(tokens);
        ParseTree tree = parser.init(); // begin parsing at init rule
        System.out.println(tree.toStringTree(parser)); // print LISP-style tree
    }
}

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>antlrtest</groupId>
    <artifactId>app1</artifactId>
    <version>1.0-SNAPSHOT</version>

    <build>
        <plugins>
            <plugin>
                <groupId>org.antlr</groupId>
                <artifactId>antlr4-maven-plugin</artifactId>
                <version>4.5</version>
                <executions>
                    <execution>
                        <id>antlr</id>
                        <goals>
                            <goal>antlr4</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>

    <dependencies>
        <dependency>
            <groupId>org.antlr</groupId>
            <artifactId>antlr4-runtime</artifactId>
            <version>4.5</version>
        </dependency>
        <dependency>
            <groupId>org.antlr</groupId>
            <artifactId>antlr4-maven-plugin</artifactId>
            <version>4.5</version>
            <type>maven-plugin</type>
        </dependency>
    </dependencies>

</project>

编译

mvn package 

成功，antlr生成的源和相应的类在target/classes中创建。

但是运行生成的 jar

java -cp target/app1-1.0-SNAPSHOT.jar Test

结果出现以下错误:

Error: A JNI error has occurred, please check your installation and 

try again
Exception in thread "main" java.lang.NoClassDefFoundError: org/antlr/v4/runtime/CharStream
    at java.lang.Class.getDeclaredMethods0(Native Method)
    at java.lang.Class.privateGetDeclaredMethods(Class.java:2701)
    at java.lang.Class.privateGetMethodRecursive(Class.java:3048)
    at java.lang.Class.getMethod0(Class.java:3018)
    at java.lang.Class.getMethod(Class.java:1784)
    at sun.launcher.LauncherHelper.validateMainClass(LauncherHelper.java:544)
    at sun.launcher.LauncherHelper.checkAndLoadMain(LauncherHelper.java:526)
Caused by: java.lang.ClassNotFoundException: org.antlr.v4.runtime.CharStream
    at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    ... 7 more

我错过了什么？

Answer 1

似乎 ANTLR 没有包含在 jar 中。必须通过类路径添加它，或者告诉 Maven 通过将其放入 jar 文件来包含其依赖项。

包含与程序集插件的依赖关系:

        <plugin>
            <artifactId>maven-assembly-plugin</artifactId>
            <configuration>
                <archive>
                    <manifest>
                        <mainClass>Test</mainClass>
                    </manifest>
                </archive>
                <descriptorRefs>
                    <descriptorRef>jar-with-dependencies</descriptorRef>
                </descriptorRefs>
            </configuration>
            <executions>
                <execution>
                    <id>make-assembly</id> <!-- this is used for inheritance merges -->
                    <phase>package</phase> <!-- bind to the packaging phase -->
                    <goals>
                        <goal>single</goal>
                    </goals>
                </execution>
            </executions>
        </plugin>

然后可以使用它进行编译

mvn clean package

或

mvn clean compile assembly:single 

可以使用执行

java -jar target/app1-1.0-SNAPSHOT-jar-with-dependencies.jar