Spring Boot+Gradle:如何构建可执行jar

Question

我试图在Spring Boot+Gradle项目中构建一个可执行的jar，但目前没有任何工作。下面是最简单的结构。可能，Gradle配置中缺少一些东西。

格雷德尔：

buildscript {
    ext {
        springBootVersion = '1.5.8.RELEASE'
    }
    repositories {
        mavenCentral()
    }
    dependencies {
        classpath("org.springframework.boot:spring-boot-gradle-plugin:${springBootVersion}")
    }
}

apply plugin: 'java'
apply plugin: 'org.springframework.boot'

group = 'com.example'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = 1.8

repositories {
    mavenCentral()
}

jar {
    manifest {
        attributes 'Main-Class': 'com.example.demo.DemoApplication'
    }
    from { configurations.compile.collect { it.isDirectory() ? it : zipTree(it) } }
}

dependencies {
    compile('org.springframework.boot:spring-boot-starter-web')
}

主配置文件：

@RestController
@SpringBootApplication
public class DemoApplication {

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

    @GetMapping(value = "/")
    public String index() {
        return "index";
    }
}

当我运行java-jar1.jar这样的jar文件时，出现了以下异常：

[main] ERROR org.springframework.boot.SpringApplication - Applicati
on startup failed
org.springframework.beans.factory.BeanDefinitionStoreException: Failed to proces
s import candidates for configuration class [com.example.demo.DemoApplication];
nested exception is java.lang.IllegalArgumentException: No auto configuration cl
asses found in META-INF/spring.factories. If you are using a custom packaging, m
ake sure that file is correct.
        at org.springframework.context.annotation.ConfigurationClassParser.proce
ssDeferredImportSelectors(ConfigurationClassParser.java:556)
        at org.springframework.context.annotation.ConfigurationClassParser.parse
(ConfigurationClassParser.java:185)
        at org.springframework.context.annotation.ConfigurationClassPostProcesso
r.processConfigBeanDefinitions(ConfigurationClassPostProcessor.java:308)
        at org.springframework.context.annotation.ConfigurationClassPostProcesso
r.postProcessBeanDefinitionRegistry(ConfigurationClassPostProcessor.java:228)
        at org.springframework.context.support.PostProcessorRegistrationDelegate
.invokeBeanDefinitionRegistryPostProcessors(PostProcessorRegistrationDelegate.ja
va:272)
        at org.springframework.context.support.PostProcessorRegistrationDelegate
.invokeBeanFactoryPostProcessors(PostProcessorRegistrationDelegate.java:92)
        at org.springframework.context.support.AbstractApplicationContext.invoke
BeanFactoryPostProcessors(AbstractApplicationContext.java:687)
        at org.springframework.context.support.AbstractApplicationContext.refres
h(AbstractApplicationContext.java:525)
        at org.springframework.boot.context.embedded.EmbeddedWebApplicationConte
xt.refresh(EmbeddedWebApplicationContext.java:122)
        at org.springframework.boot.SpringApplication.refresh(SpringApplication.
java:693)
        at org.springframework.boot.SpringApplication.refreshContext(SpringAppli
cation.java:360)
        at org.springframework.boot.SpringApplication.run(SpringApplication.java
:303)
        at org.springframework.boot.SpringApplication.run(SpringApplication.java
:1118)
        at org.springframework.boot.SpringApplication.run(SpringApplication.java
:1107)
        at com.example.demo.DemoApplication.main(DemoApplication.java:13)
Caused by: java.lang.IllegalArgumentException: No auto configuration classes fou
nd in META-INF/spring.factories. If you are using a custom packaging, make sure
that file is correct.
        at org.springframework.util.Assert.notEmpty(Assert.java:277)
        at org.springframework.boot.autoconfigure.AutoConfigurationImportSelecto
r.getCandidateConfigurations(AutoConfigurationImportSelector.java:153)
        at org.springframework.boot.autoconfigure.AutoConfigurationImportSelecto
r.selectImports(AutoConfigurationImportSelector.java:95)
        at org.springframework.context.annotation.ConfigurationClassParser.proce
ssDeferredImportSelectors(ConfigurationClassParser.java:547)
        ... 14 common frames omitted

可能出了什么问题？

Answer 1

在Boot2.x中，bootJar和bootWar任务负责打包应用程序。

bootJar任务负责创建可执行jar文件。一旦应用java插件，它就会自动创建。

如果没有生成可执行的JAR/WAR文件，请手动运行下面的gradle任务。

$./gradlew bootJar

$./gradlew bootWar