Tomcat 9中只有这些目录了: conf,    logs,    bin, lib, temp, work, webapps.
并没有下面这些类加载器对应的common/shared/server目录，是需要自己手工创建吗？
CommonClassLoader对应<Tomcat>/common/*
CatalinaClassLoader对应 <Tomcat >/server/*
SharedClassLoader对应 <Tomcat >/shared/*
WebAppClassloader对应 <Tomcat >/webapps/<app>/WEB-INF/*目录

老师，请教下，我用的spring-boot，把相关spring的包都放在了xx/tomcat8.5.50/shared下面，其中有2个是redis相关的jar包（jedis-2.9.0.jar,spring-data-redis-1.8.7.RELEASE.jar）, 业务代码存数据到redis时是setObject(String key, Object value)，其中value是一个业务对象实例如Student（这个类在webapp/WEB-INF/classes下面）， 运行没有问题，但是取数据时，解析报错，Student对象找不到：
org.springframework.data.redis.serializer.SerializationException: Cannot deserialize; nested exception is org.springframework.core.serializer.support.SerializationFailedException: Failed to deserialize payload. Is the byte array a result of corresponding serialization for DefaultDeserializer?; nested exception is org.springframework.core.NestedIOException: Failed to deserialize object type; nested exception is java.lang.ClassNotFoundException: com.xxx.xxx.domain.Student
    at org.springframework.data.redis.serializer.JdkSerializationRedisSerializer.deserialize(JdkSerializationRedisSerializer.java:82)
    at org.springframework.data.redis.core.AbstractOperations.deserializeValue(AbstractOperations.java:318)
    at org.springframework.data.redis.core.AbstractOperations$ValueDeserializingRedisCallback.doInRedis(AbstractOperations.java:58)
    at org.springframework.data.redis.core.RedisTemplate.execute(RedisTemplate.java:207)
    at org.springframework.data.redis.core.RedisTemplate.execute(RedisTemplate.java:169)
    at org.springframework.data.redis.core.AbstractOperations.execute(AbstractOperations.java:91)
    at org.springframework.data.redis.core.DefaultValueOperations.get(DefaultValueOperations.java:43)

所以我理解是SharedClassLoader无法加载webAppClassLoader加载的类，那该如何解决这个问题呢，因为业务代码暂时不能改。

老师，您好：
我对Thread.currentThread().setContextClassLoader(ClassLoader cl)用法一直有个疑问：
- setContextClassLoader以后是不是只能显示地通过getContextClassLoader获取ClassLoader后调用loadClass(String name, boolean resolve)方法加载类才能是自定义加载器加载的(验证方法：打印obj.getClass().getClassLoader())？
- setContextClassLoader以后通过Class.forName(String name)方法等反射得到的类是不是就只能是AppClassLoader加载的？
我做了个实验：
自定义类加载器：
public class DIYClassLoader extends URLClassLoader {
    public DIYClassLoader(URL[] urls) { super(urls); }
    /**
     * 策略很简单：
     * 1)、首先尝试ExtClassLoader|BootstrapClassLoader加载
     * 2)、之后尝试自己加载
     * 3)、最后尝试真正父加载器加载
     */
    @Override
    protected Class<?> loadClass(String name, boolean resolve) throws ClassNotFoundException {
        Class<?> c = findLoadedClass(name);
        ClassLoader parent = getParent();
        if (parent != null) {
            ClassLoader ecl = parent;
            while (ecl.getParent() != null)// 找ExtClassLoader
                ecl = ecl.getParent();
            try {
                c = ecl.loadClass(name);
            } catch (ClassNotFoundException e) { }
            if (c == null) {
                try {
                    c = findClass(name);// DIYClassLoader自己来
                } catch (ClassNotFoundException e) {}
                if (c == null) {
                    // 尝试真正父加载器加载，多半是AppClassLoader
                    c = parent.loadClass(name);
                }
            }
        }else {
            // 直接自己尝试加载
            c = findClass(name);
        }
        if (resolve)
            resolveClass(c);
        return c;
    }
}
main方法：
URL url = Main.class.getClassLoader().getResource(".");
DIYClassLoader scl = new DIYClassLoader(new URL[] {url});
Thread.currentThread().setContextClassLoader(scl);
Class clazz = Class.forName("xx.xx.Xxx");
// sun.misc.Launcher$AppClassLoader@18b4aac2
clazz = scl.loadClass("xx.xx.Xxx");
// xx.xx.DIYClassLoader@682a0b20
不知道我把问题描述清楚了吗？还望老师解答