错误的写法

java -jar ruoyi-admin.jar -Dloader.path=.\lib   

正确的写法

java -Dloader.path=./lib -jar ruoyi-admin.jar

或者

java  -jar -Dloader.path=./lib ruoyi-admin.jar

-Dloader.path必须卸载 -jar ruoyi-admin.jar之前，其实我试过了-Dloader.path命令只要在ruoyi-admin.jar之前即可

E:\workspace\aliyun_codeup\LogisticsManageSys\ruoyi-admin\target>java -jar ruoyi-admin.jar -Dloader.path=.\lib
Exception in thread "main" java.lang.reflect.InvocationTargetException
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
        at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.base/java.lang.reflect.Method.invoke(Method.java:568)
        at org.springframework.boot.loader.MainMethodRunner.run(MainMethodRunner.java:49)
        at org.springframework.boot.loader.Launcher.launch(Launcher.java:108)
        at org.springframework.boot.loader.Launcher.launch(Launcher.java:58)
        at org.springframework.boot.loader.PropertiesLauncher.main(PropertiesLauncher.java:467)
Caused by: java.lang.NoClassDefFoundError: org/springframework/boot/SpringApplication
        at com.ruoyi.RuoYiApplication.main(RuoYiApplication.java:18)
        ... 8 more
Caused by: java.lang.ClassNotFoundException: org.springframework.boot.SpringApplication
        at java.base/java.net.URLClassLoader.findClass(URLClassLoader.java:445)
        at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:587)
        at org.springframework.boot.loader.LaunchedURLClassLoader.loadClass(LaunchedURLClassLoader.java:151)
        at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:520)