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问题描述

最新将Spring Boot项目升级到JDK 11，运行时发现警告如下：

WARNING: An illegal reflective access operation has occurred
WARNING: Illegal reflective access by org.springframework.cglib.core.ReflectUtils (file:/D:/Android/.gradle/caches/modules-2/files-2.1/org.springframework/spring-core/5.2.0.RELEASE/e0e1b3c304f70ed19d7905975f6f990916ada219/spring-core-5.2.0.RELEASE.jar) to method java.lang.ClassLoader.defineClass(java.lang.String,byte[],int,int,java.security.ProtectionDomain)
WARNING: Please consider reporting this to the maintainers of org.springframework.cglib.core.ReflectUtils
WARNING: Use --illegal-access=warn to enable warnings of further illegal reflective access operations
WARNING: All illegal access operations will be denied in a future release

解决方案

方案一

增加 JVM 启动参数：

java --illegal-access=deny

Java 9 中这个参数默认是：permit

方案二

在启动类增加以下方法，亲测试 jdk 11 有效

public static void disableWarning() {
    try {
        Field theUnsafe = Unsafe.class.getDeclaredField("theUnsafe");
        theUnsafe.setAccessible(true);
        Unsafe u = (Unsafe) theUnsafe.get(null);

        Class cls = Class.forName("jdk.internal.module.IllegalAccessLogger");
        Field logger = cls.getDeclaredField("logger");
        u.putObjectVolatile(cls, u.staticFieldOffset(logger), null);
    } catch (Exception e) {
        // ignore
    }
}

启动 Spring Boot 时调用一下上面的方法

public static void main(String[] args) {
    disableWarning(); //禁用警告
    SpringApplication.run(AppApplication.class, args);
}

参考

参考：
https://stackoverflow.com/questions/46454995/how-to-hide-warning-illegal-reflective-access-in-java-9-without-jvm-argument
https://blog.csdn.net/qq_25958497/article/details/87258748
https://stackoverflow.com/questions/53790182/get-the-current-value-of-illegal-access-setting-in-java