What does Liu written by Li Shangyin mean?

Li Shangyin's Willow is a unique poem that sings willow songs to hurt oneself and pour out one's worries. The poem is about the willow in autumn, but the poet doesn't start from the present, but remembers its spring scene first, and then returns to the willow in front of him. Write willow in every sentence, but there is not a word "willow" in the whole article; Every sentence is a scene; Every sentence praises things, but every sentence writes people, expressing the lamentation for the sparse and declining autumn willow. The autumn willow in the poem, which experienced the disparity between the past and the present, is a vivid portrayal of the poet's self-sighing life experience.