使用 Maven 插件将 class（字节码文件），resource（资源文件），lib（依赖的jar包）分开打包

1. 在pom文件中对各个插件进行配置

<?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>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.1.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>demo</artifactId>
    <version>1.0</version>
    <name>demo</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
        <encoding>UTF-8</encoding>
        <maven-compiler-plugin-version>3.8.0</maven-compiler-plugin-version>
        <maven-jar-plugin-version>3.1.0</maven-jar-plugin-version>
        <maven-source-plugin-version>3.0.1</maven-source-plugin-version>
        <maven-assembly-plugin-version>3.1.0</maven-assembly-plugin-version>
        <maven-dependency-plugin-version>3.1.0</maven-dependency-plugin-version>
        <maven-resources-plugin-version>3.1.0</maven-resources-plugin-version>

    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-thymeleaf</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <!-- 生成的项目jar包的名字-->
        <finalName>demo-findName</finalName>
        <!--源代码路径-->
        <sourceDirectory>src/main/java</sourceDirectory>

        <!--maven-resources-plugin 插件打包resource文件时会参考此节点的配置-->
        <resources>
            <!--resource 子节点可通过配置将制定目录的文件在打包后拷贝到制定目录-->
            <!-- 把src/main/resources目录下所有的文件拷贝到conf目录中 -->
            <resource>
                <directory>src/main/resources</directory>
                <targetPath>${project.build.directory}/conf</targetPath>
            </resource>
        </resources>

        <plugins>
            <!--编译插件-->
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>${maven-compiler-plugin-version}</version>
                <configuration>
                    <encoding>${encoding}</encoding>
                    <source>${java.version}</source>
                    <target>${java.version}</target>
                </configuration>
            </plugin>

            <!--将项目的源代码的class文件打包到一个jar包-->
            <!--jar包默认在target目录下-->
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-jar-plugin</artifactId>
                <version>${maven-jar-plugin-version}</version>
                <configuration>
                    <archive>
                        <!-- 生成的jar中，不要包含pom.xml和pom.properties这两个文件 -->
                        <addMavenDescriptor>false</addMavenDescriptor>
                        <manifest>
                            <!-- 是否要把第三方jar放到manifest的classpath中 -->
                            <addClasspath>true</addClasspath>
                            <!-- 生成的manifest中classpath的前缀，因为要把第三方jar放到lib目录下，所以classpath的前缀是lib/ -->
                            <classpathPrefix>lib/</classpathPrefix>
                            <!-- 应用的main class -->
                            <mainClass>com.example.demo.DemoApplication</mainClass>
                        </manifest>
                    </archive>
                </configuration>
            </plugin>

            <!-- 用于拷贝maven依赖的plugin -->
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-dependency-plugin</artifactId>
                <version>${maven-dependency-plugin-version}</version>
                <executions>
                    <execution>
                        <id>copy-dependencies</id>
                        <phase>package</phase>
                        <goals>
                            <goal>copy-dependencies</goal>
                        </goals>
                        <configuration>
                            <!-- 把依赖的所有maven jar包拷贝到lib目录中 -->
                            <outputDirectory>${project.build.directory}/lib</outputDirectory>
                        </configuration>
                    </execution>
                </executions>
            </plugin>

            <!-- 用于拷贝resource的plugin -->
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-resources-plugin</artifactId>
                <version>${maven-resources-plugin-version}</version>
                <configuration>
                    <encoding>${encoding}</encoding>
                    <outputDirectory>${project.build.directory}/conf</outputDirectory>
                </configuration>
            </plugin>

        </plugins>

    </build>

</project>

2. 打包后的 target 目录结构

　　conf：资源文件目录

　　lib：依赖的jar包目录

　　demo-findName：将class文件打包生成的jar包

3. 运行项目

　　把上述三个目录文件放在同一级目录下，

　　执行 java -jar 生成的jar包名字

　　即可启动项目