打印log的方式

学习系统的BroadcastFilter类的方法

    public String toString() {
        StringBuilder sb = new StringBuilder();
        sb.append("BroadcastFilter{");
        sb.append(Integer.toHexString(System.identityHashCode(this)));
        sb.append(" u");
        sb.append(owningUserId);
        sb.append(' ');
        sb.append(receiverList);
        sb.append('}');
        return sb.toString();
    }