java - Mvn clean package 未正确创建 JAR 文件

Question

note: I tried out the suggested answers in the "possible-duplicated"-questions, they did sadly not help me. I edited my question a bit.

我设置了一个 Spring-Boot 应用程序(可以从 Spring Tool Suite IDE 执行)。现在我想构建 jar 文件并执行它。我尝试过的:

cd %path_to_my_project_root%
mvn clean package
cd target
java -jar myApp.jar

错误是(翻译后，可能是错误的措辞):

no main manifest attribute in myApp.jar

我尝试了不同平台上建议的不同解决方案(例如 here 和 here )。然而，据我了解，这似乎是我的 POM.xml 的问题。

我的Pom:

<?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.demo</groupId>
    <artifactId>myApp</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>myApp</name>
    <description>desc</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.1.RELEASE</version>
        <relativePath /> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-ldap</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-rest</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-security</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-tomcat</artifactId>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.restdocs</groupId>
            <artifactId>spring-restdocs-mockmvc</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.security</groupId>
            <artifactId>spring-security-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-autoconfigure</artifactId>
            <type>jar</type>
        </dependency>
     </dependencies>

     <build>
        <pluginManagement>
            <plugins>
                <plugin>
                    <groupId>org.codehaus.mojo</groupId>
                    <artifactId>exec-maven-plugin</artifactId>
                    <executions>
                        <execution>
                            <phase>validate</phase>
                            <goals>
                                <goal>exec</goal>
                            </goals>
                        </execution>
                    </executions>
                    <configuration>
                        <executable>ng</executable>
                        <workingDirectory>src/main/ui</workingDirectory>
                        <argument>
                            <argument>build</argument>
                        </argument>
                    </configuration>
                </plugin>
                <plugin>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-maven-plugin</artifactId>
                    <executions>
                        <execution>
                            <goals>
                                <goal>repackage</goal>
                            </goals>
                        </execution>
                    </executions>
                </plugin>
            </plugins>
        </pluginManagement>
    </build>
</project>

我查找了我的 Manifest.MF，内容如下:

Manifest-Version: 1.0
Implementation-Title: myApp
Implementation-Version: 0.0.1-SNAPSHOT
Built-By: me
Implementation-Vendor-Id: myPackage
Created-By: Apache Maven 3.6.0
Build-Jdk: 1.8.0_191
Implementation-URL: my_Url

我似乎缺少什么:

我查找了 jar 文件，我注意到了一些事情:

• 我缺少 .jar.original 文件
• 我的 Manifest.MF 中没有 Spring-Boot-Version、Main-Class、Start-Class 和 Boot-Inf 参数
• 我的jar仅包含三样东西:META-INF、com(已编译的类)和application.properties文件。里面通常还有很多东西。

我的应用程序属性

spring.datasource.driverClassName=com.mysql.cj.jdbc.Driver
spring.datasource.url=jdbc:mysql://external.url/dbname?useUnicode=true&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=UTC
spring.datasource.username=user
spring.datasource.password=pass

spring.jpa.database = MYSQL
spring.jpa.show-sql = true

Answer 1

您缺少此 Maven 属性:

<start-class>com.demo.MainClass</start-class>

(这必须包含调用 SpringApplication.run(..) 的主类)