"Need to invoke method '%s' found on proxy for target class '%s' but cannot be delegated to target bean. Switch its visibility to package or protected." SpringBoot定時任務注解的方法為private報錯

解決辦法，注解的方法改成public
原因：

1.在@EnableScheduling注解里導入了SchedulingConfiguration類

2.該類會對有@scheduler注解的方法進行處理

protected void processScheduled(Scheduled scheduled, Method method, Object bean) {
try {
Assert.isTrue(method.getParameterTypes().length == 0,
"Only no-arg methods may be annotated with @Scheduled");

Method invocableMethod = AopUtils.selectInvocableMethod(method, bean.getClass());
Runnable runnable = new ScheduledMethodRunnable(bean, invocableMethod);
.....}

3.在selectInvocableMethod(method, bean.getClass())該方法里會進行校驗

public static Method selectInvocableMethod(Method method, Class<?> targetType) {
Method methodToUse = MethodIntrospector.selectInvocableMethod(method, targetType);
if (Modifier.isPrivate(methodToUse.getModifiers()) && !Modifier.isStatic(methodToUse.getModifiers()) &&
SpringProxy.class.isAssignableFrom(targetType)) {
throw new IllegalStateException(String.format(
"Need to invoke method '%s' found on proxy for target class '%s' but cannot " +
"be delegated to target bean. Switch its visibility to package or protected.",
method.getName(), method.getDeclaringClass().getSimpleName()));
}
return methodToUse;
}

當方法為private修飾，同時不是static的，同時不是SpringProxy的子類就會拋出該異常