前言

假设原有代码如下：

package org.example;

import cn.hutool.crypto.SmUtil;

public class App 
{
    public static void main( String[] args ) {
        String digestHex = SmUtil.sm3("hello d4m1ts");
        System.out.println(digestHex);
    }
}

pom.xml如下

<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>org.example</groupId>
  <artifactId>test1</artifactId>
  <version>1.0-SNAPSHOT</version>
  <packaging>jar</packaging>

  <name>test1</name>
  <url>http://maven.apache.org</url>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
  </properties>

  <dependencies>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>3.8.1</version>
      <scope>test</scope>
    </dependency>
    <dependency>
      <groupId>cn.hutool</groupId>
      <artifactId>hutool-all</artifactId>
      <version>5.8.25</version>
    </dependency>
    <dependency>
      <groupId>org.bouncycastle</groupId>
      <artifactId>bcpkix-jdk18on</artifactId>
      <version>1.78.1</version>
    </dependency>
  </dependencies>
  <build>
    <plugins>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-compiler-plugin</artifactId>
        <configuration>
          <source>7</source>
          <target>7</target>
        </configuration>
      </plugin>
    </plugins>
  </build>
</project>

直接 mvn package 打包成jar运行，会提示：没有主清单属性

方法一：使用maven-assembly-plugin

在pom.xml中增加如下插件内容，其中 mainClass 为程序启动的java class。

<plugin>
  <groupId>org.apache.maven.plugins</groupId>
  <artifactId>maven-assembly-plugin</artifactId>
  <executions>
    <execution>
      <phase>package</phase>
      <goals>
        <goal>single</goal>
      </goals>
      <configuration>
        <archive>
          <manifest>
            <mainClass>
              org.example.App
            </mainClass>
          </manifest>
        </archive>
        <descriptorRefs>
          <descriptorRef>jar-with-dependencies</descriptorRef>
        </descriptorRefs>
      </configuration>
    </execution>
  </executions>
</plugin>