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.csdn.net/yulei_qq/article/details/82423683