无法找到合适的主类，请添加“ mainClass”属性

Question

我完全理解此错误消息的含义，但是如何解决？ Intellij不允许我单击主应用程序类。

  

org.springframework.boot：spring-boot-maven-plugin：2.1.7.RELEASE：在项目XprojApplication上运行（default-cli）：无法找到合适的主类，请添加一个'mainClass'属性-> [帮助1]

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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
        <modelVersion>4.0.0</modelVersion>
        <parent>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-parent</artifactId>
            <version>2.1.7.RELEASE</version>
            <relativePath/> <!-- lookup parent from repository -->
        </parent>
        <groupId>dev.house</groupId>
        <artifactId>xproj</artifactId>
        <version>0.0.1-SNAPSHOT</version>
        <name>15house</name>

        <description>Demo project for Spring Boot</description>

        <properties>
            <java.version>1.8</java.version>
        </properties>

        <packaging>war</packaging>
        <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-web</artifactId>
                <exclusions>
                    <exclusion>
                        <groupId>org.springframework.boot</groupId>
                        <artifactId>spring-boot-starter-tomcat</artifactId>
                    </exclusion>
                </exclusions>

            </dependency>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-tomcat</artifactId>
                <scope>provided</scope>
            </dependency>
            <dependency>
                <groupId>org.apache.tomcat</groupId>
                <artifactId>tomcat-servlet-api</artifactId>
                <version>8.0.36</version>
                <scope>provided</scope>
            </dependency>

            <dependency>
                <groupId>com.h2database</groupId>
                <artifactId>h2</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-test</artifactId>
                <scope>test</scope>
            </dependency>
            <dependency>
                <groupId>com.fasterxml.jackson.core</groupId>
                <artifactId>jackson-databind</artifactId>
                <version>2.9.4</version>
            </dependency>

            <dependency>
                <groupId>com.fasterxml.jackson.core</groupId>
                <artifactId>jackson-core</artifactId>
                <version>2.9.4</version>
            </dependency>

            <dependency>
                <groupId>com.fasterxml.jackson.core</groupId>
                <artifactId>jackson-annotations</artifactId>
                <version>2.9.4</version>
            </dependency>
        </dependencies>

        <build>
            <plugins>
                <plugin>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-maven-plugin</artifactId>
                </plugin>

                <plugin>
                    <artifactId>maven-assembly-plugin</artifactId>
                    <executions>
                        <execution>
                            <phase>package</phase>
                            <goals>
                                <goal>single</goal>
                            </goals>
                        </execution>
                    </executions>
                    <configuration>
    <!--                    <archive>-->
    <!--                        <manifest>-->
    <!--                            <addClasspath>true</addClasspath>-->
    <!--                            <mainClass>dev.house.XprojApplication</mainClass>-->
    <!--                        </manifest>-->
    <!--                    </archive>-->
                        <descriptorRefs>
                            <descriptorRef>jar-with-dependencies</descriptorRef>
                        </descriptorRefs>
                    </configuration>
                </plugin>

            </plugins>
            <directory>/Users/poc/workspace/tw-real-estate-service-manager/webapps/15house</directory>
            <finalName>15house</finalName>
        </build>

    </project>

Answer 1

似乎您的目录没有正确标记。

由于您使用的是Maven，因此我假设您具有以下结构。

请通过右键单击文件夹并遵循java子菜单，确保将Sources Root目录标记为Mark Directory as。您可能想要对resources目录执行相同操作，将其标记为Resources Root。

Answer 2

如果您想在春季启动时使用可启动的jar，只需在pom.xml中使用以下配置，就不需要 maven-assembly-plugin

<plugin>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-maven-plugin</artifactId>
    <executions>
        <execution>
            <goals>
                <goal>repackage</goal>
            </goals>
            <configuration>
                <start-class>org.springframework.boot.loader.JarLauncher</start-class>
            </configuration>
        </execution>
    </executions>
</plugin>