java -jar 和 java -cp 区别

原创转载请注明出处：https://www.cnblogs.com/agilestyle/p/12022527.html

Project Directory

SRC

MainTest.java

 package org.fool.test;

 public class MainTest {
     public static void main(String[] args) {
         System.out.println("Hello Jar");
     }
 }

Maven Dependency

 <?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>org.fool.test</groupId>
     <artifactId>hello-jar</artifactId>
     <version>1.0-SNAPSHOT</version>

     <build>
         <plugins>
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-compiler-plugin</artifactId>
                 <version>3.8.1</version>
                 <configuration>
                     <source>1.8</source>
                     <target>1.8</target>
                 </configuration>
             </plugin>

             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-assembly-plugin</artifactId>
                 <version>3.2.0</version>
                 <configuration>
                     <appendAssemblyId>false</appendAssemblyId>
                     <descriptorRefs>
                         <descriptorRef>jar-with-dependencies</descriptorRef>
                     </descriptorRefs>
                     <archive>
                         <manifest>
                             <mainClass>org.fool.test.MainTest</mainClass>
                         </manifest>
                     </archive>
                 </configuration>
                 <executions>
                     <execution>
                         <id>make-assembly</id>
                         <phase>package</phase>
                         <goals>
                             <goal>single</goal>
                         </goals>
                     </execution>
                 </executions>
             </plugin>
         </plugins>
     </build>

 </project>

Note:

maven-assembly-plugin 中指定了 mainClass

clean package 后分别执行

java -jar

 $ java -jar hello-jar-1.0-SNAPSHOT.jar
 Hello Jar

java -cp

 $ java -cp hello-jar-1.0-SNAPSHOT.jar org.fool.test.MainTest
 Hello Jar

maven-assembly-plugin 中不指定 mainClass

clean package 后再次分别执行

java -jar

 $ java -jar hello-jar-1.0-SNAPSHOT.jar
 no main manifest attribute, in hello-jar-1.0-SNAPSHOT.jar

java -cp

 $ java -cp hello-jar-1.0-SNAPSHOT.jar org.fool.test.MainTest
 Hello Jar

Reference

https://www.jianshu.com/p/eabfb61e072a

https://blog.****.net/yulei_qq/article/details/82423683