java.lang.NoClassDefFoundError：尝试运行 jar 时

java.lang.NoClassDefFoundError: when trying to run jar

提问by Quillion

I have a spring boot project using gradle

我有一个使用 gradle 的 spring boot 项目

apply plugin: 'java'
apply plugin: 'idea'
apply plugin: 'jetty'
apply plugin: 'war'
apply plugin: 'org.springframework.boot'

repositories {
    mavenCentral()
}

dependencies {
    compile("org.springframework.boot:spring-boot-starter-web:1.5.1.RELEASE") {
        exclude module: "spring-boot-starter-tomcat"
    }
    compile group: 'org.springframework.boot', name: 'spring-boot-starter-jetty', version: '1.5.1.RELEASE'
    compile group: 'org.springframework.boot', name: 'spring-boot-starter-actuator', version: '1.5.1.RELEASE'
    compile group: 'org.springframework', name: 'spring-webmvc', version: '4.3.6.RELEASE'
    compile group: 'org.springframework', name: 'spring-context-support', version: '4.3.6.RELEASE'
    compile group: 'org.springframework', name: 'spring-orm', version: '4.3.6.RELEASE'
    compile group: 'javax.servlet', name: 'javax.servlet-api', version: '3.1.0'
    compile group: 'org.freemarker', name: 'freemarker', version: '2.3.23'
    compile group: 'mysql', name: 'mysql-connector-java', version: '6.0.5'
    compile group: 'org.hibernate', name: 'hibernate-core', version: '5.1.4.Final'
    compile group: 'commons-validator', name: 'commons-validator', version: '1.5.1'
    compile group: 'junit', name: 'junit', version: '4.12'
    compile group: 'org.springframework.boot', name: 'spring-boot-starter-test', version: '1.5.1.RELEASE'
}

task wrapper(type: Wrapper) {
    gradleVersion = '2.2'
}

buildscript {
    repositories {
        mavenCentral()
    }
    dependencies {
        classpath("org.springframework.boot:spring-boot-gradle-plugin:1.5.1.RELEASE")
    }
}

jar {
    baseName = 'base-name'
    version = '0.1.0'
    manifest {
        attributes 'Main-Class': 'some.application.Application'
    }
}

sourceCompatibility = 1.8
targetCompatibility = 1.8

I build using
./gradlew clean jar
Then try to run using
java -jar <jar-name>.jar

我构建使用
./gradlew clean jar
然后尝试运行使用
java -jar <jar-name>.jar

However I get an error saying

但是我收到一个错误说

Exception in thread "main" java.lang.NoClassDefFoundError: org/springframework/boot/SpringApplication
        at some.application.Application.main(Application.java:11)
Caused by: java.lang.ClassNotFoundException: org.springframework.boot.SpringApplication
        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)
        ... 1 more

I am so confused as to why I can run it in IDE but not as a jar. Also I found out that my jar doesn't contain any libraries at all.

我很困惑为什么我可以在 IDE 中运行它，但不能作为 jar 运行。我还发现我的 jar 根本不包含任何库。

EDIT:

编辑：

This is my Application.class

这是我的 Application.class

package some.application;

打包 some.application;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class Application
{
    public static void main(String[] args)
    {
        SpringApplication.run(Application.class, args);
    }
}

回答by Sasha Shpota

This is because your dependencies are not included into the end jar file.

这是因为您的依赖项未包含在最终 jar 文件中。

Take a look on the examples hereor here.

查看此处或此处的示例。

Or alternatively use ./gradlew clean buildthat should automatically pack the app correctly. Take a look on the official guide

或者使用./gradlew clean build应该自动正确打包应用程序的方法。看看官方指南

回答by K. Symbol

1. Define a task called fatJarin build.gradle:

1. 定义一个名为任务fatJar中build.gradle：

jar {
    baseName = 'base-name'
    version = '0.1.0'
    manifest {
        attributes(
                'Main-Class': 'com.github:'
        )
    }
}

task fatJar(type: Jar) {
    manifest.from jar.manifest
//    classifier = 'all'
    from {
        configurations.runtime.collect { it.isDirectory() ? it : zipTree(it) }
    } {
        exclude "META-INF/*.SF"
        exclude "META-INF/*.DSA"
        exclude "META-INF/*.RSA"
    }
    with jar
}

artifacts {
    archives fatJar
}

1. Run gradle fatJaror ./gradlew fatJarto generate a jarfile with all dependencies, which can run independently but may be pretty large in size (that's why it's called a fat jar).

2. 运行gradle fatJar或./gradlew fatJar生成一个jar包含所有依赖项的文件，该文件可以独立运行但可能非常大（这就是为什么它被称为胖罐）。