如果我根据parentFolderUUID和username来查询文件和文件夹网盘的文件列表树状结构并且支持后退到上一级目录如何实现用Vue3来实现

首先，需要定义一个组件来展示文件列表树状结构，可以使用递归组件来实现。具体实现可以参考以下代码：

<template>
  <div>
    <div v-for="(item, index) in folderList" :key="index">
      <div @click="goToFolder(item)">
        {{ item.name }}
      </div>
      <div v-if="item.children && item.children.length">
        <FolderList :folderList="item.children" :parentFolderUUID="item.uuid" :username="username" />
      </div>
    </div>
  </div>
</template>

<script>
import { getFolderList } from '@/api/folder'

export default {
  name: 'FolderList',
  props: {
    folderList: {
      type: Array,
      required: true
    },
    parentFolderUUID: {
      type: String,
      required: true
    },
    username: {
      type: String,
      required: true
    }
  },
  data () {
    return {
      folderList: []
    }
  },
  methods: {
    async goToFolder (folder) {
      if (folder.type === 'folder') {
        this.folderList = await getFolderList(folder.uuid, this.username)
      }
    }
  }
}
</script>

然后，在父组件中，需要定义一个方法来获取根目录的文件列表，并将其传递给子组件。同时，还需要定义一个方法来处理后退操作，即返回上一级目录。具体实现可以参考以下代码：

<template>
  <div>
    <button v-if="parentFolderUUID" @click="goBack">返回上一级</button>
    <FolderList v-if="folderList && folderList.length" :folderList="folderList" :parentFolderUUID="parentFolderUUID" :username="username" />
  </div>
</template>

<script>
import FolderList from '@/components/FolderList'
import { getFolderList } from '@/api/folder'

export default {
  name: 'FileTree',
  components: {
    FolderList
  },
  props: {
    parentFolderUUID: {
      type: String,
      default: ''
    },
    username: {
      type: String,
      required: true
    }
  },
  data () {
    return {
      folderList: []
    }
  },
  async created () {
    if (!this.parentFolderUUID) {
      this.folderList = await getFolderList('', this.username)
    }
  },
  methods: {
    async goBack () {
      const parentFolder = await getFolder(this.parentFolderUUID)
      this.folderList = await getFolderList(parentFolder.parentFolderUUID, this.username)
      this.parentFolderUUID = parentFolder.parentFolderUUID
    }
  }
}
</script>

最后，在父组件中，将FileTree组件挂载到页面上，并传递需要查询的parentFolderUUID和username参数。具体实现可以参考以下代码：

<template>
  <div>
    <FileTree :parentFolderUUID="parentFolderUUID" :username="username" />
  </div>
</template>

<script>
import FileTree from '@/components/FileTree'

export default {
  name: 'App',
  components: {
    FileTree
  },
  data () {
    return {
      parentFolderUUID: '',
      username: 'testuser'
    }
  }
}
</script>