java - Gradle 运行 jar 时出现 NoClassDefFoundError

Question

我正在尝试设置一个 Gradle 项目，其中包含一些 Velocity 函数。

到目前为止我有以下文件:

src/main/java/com/veltes/velotest.java:

package com.veltes;

import org.apache.velocity.app.VelocityEngine;
import org.apache.velocity.Template;
import org.apache.velocity.VelocityContext;
import org.apache.velocity.exception.MethodInvocationException;
import org.apache.velocity.exception.ParseErrorException;
import org.apache.velocity.exception.ResourceNotFoundException;
import org.apache.velocity.runtime.RuntimeConstants;
import org.apache.velocity.runtime.resource.loader.ClasspathResourceLoader;

import java.io.*;

public class velotest {
    public static void main(String[] args) {

        try {
            VelocityEngine ve = new VelocityEngine();
            ve.setProperty(RuntimeConstants.RESOURCE_LOADER, "classpath");
            ve.setProperty("classpath.resource.loader.class", ClasspathResourceLoader.class.getName());
            ve.init();
            VelocityContext context = new VelocityContext();
            context.put("name", "World");
            Template t = ve.getTemplate("com/veltes/velotest.vm");
            StringWriter writer = new StringWriter();
            t.merge(context, writer);
            System.out.println(writer.toString());

            File logFile = new File("C:/users/xxxx/Desktop/velotest.html");

            try {
                writeFile(logFile, t, context);
            }
            catch (IOException io) {
            }
        } catch (Exception e) {
        }

    }

    private static void writeFile(File logFile, Template t, VelocityContext context) throws IOException {
        Writer logWriter;

        logWriter = new BufferedWriter(new FileWriter(logFile));
        try {
            t.merge(context, logWriter);
        }
        catch (ResourceNotFoundException rnfe) {
        }
        catch (ParseErrorException pee) {
        }
        catch (MethodInvocationException mie) {
        }
        catch (Exception e) {
        }
        logWriter.flush();
        logWriter.close();
    }

}

build.gradle:

group 'velocitytest'
version '1.0-SNAPSHOT'

apply plugin: 'groovy'
apply plugin: 'java'

sourceCompatibility = 1.5

repositories {
    mavenCentral()
    mavenLocal()
}

dependencies {
    compile 'org.codehaus.groovy:groovy-all:2.3.11'
    testCompile group: 'junit', name: 'junit', version: '4.11'

    compile 'velocity:velocity:1.4'
}

现在，当我运行 gradle assemble 和 gradle build 时一切都很好，但是当我尝试运行项目时(与在 build/libs/中运行构建的 jar 和 for在 IntelliJ 中运行 velotest 类)，我收到以下错误:

Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/commons/collections/ExtendedProperties
at org.apache.velocity.runtime.RuntimeInstance.< init >(RuntimeInstance.java:183)
at org.apache.velocity.app.VelocityEngine.(VelocityEngine.java:60) at com.veltes.velotest.main(velotest.java:23)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:497)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:147)
Caused by: java.lang.ClassNotFoundException: org.apache.commons.collections.ExtendedProperties
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)
... 8 more

有点奇怪，build/tmp/中没有jar

你们有人知道解决办法吗？

Answer 1

如果您希望能够运行它，则需要创建一个可运行的 jar。

您可以使用 shadojar 插件或扩展 jar 任务将运行时依赖打包到工件中。

jar {
    archiveName = 'Name.jar'

    manifest {
        attributes 'Main-Class': 'your.main.class',
                'Class-Path': configurations.runtime.files.collect { "lib/$it.name" }.join(' '),
                'Implementation-Version': project.version
    }

    from(configurations.compile.collect { it.isDirectory() ? it : zipTree(it) }) {}
}

对于智能问题:

apply plugin: 'idea'

然后运行 ​​gradle idea 任务，这将刷新项目中的 .iws .ipr .iml 文件并同步类路径。或者，如果您使用 IntelliJ 支持(尚不理想)，请尝试在那里刷新它。我认为2017.1.3版本中gradle集成好一点。