html

<el-upload 
    :action="uploadFileReq" 
    ref="upload" 
    :on-change="handleChange" 
    :on-success="handleSuccess" 
    :on-progress="handleProgress" 
    :auto-upload="false" 
    :file-list="fileList" 
    :show-file-list="false" drag>

    <i class="el-icon-upload"></i>
    <div class="el-upload__text">将文件拖到此处，或<em>点击上传</em></div>

</el-upload>

<el-button type="primary" @click="sendClick">发送</el-button>

 方法一

手动使用submit()上传

        // 文件操作
        handleChange(file, fileList) {
            console.log(file)
            console.log(fileList)
        },
        // 点击上传
        sendClick() {
            this.$refs.upload.submit()
        },
        // 文件上传时
        handleProgress(event) {
            console.log(event)
        },
        // 上传成功
        handleSuccess(res) {
            console.log(res)
        },

方法二

使用axios上传

// 文件操作
handleChange(file, fileList) {
    console.log(file)
    console.log(fileList)
    let formData = new FormData()
    formData.append('file', file.raw)
    this.files = formData
},
// 点击上传
async sendClick() {
    const { data: res } = await axios({
        method: 'post',
        url: this.uploadFileReq,
        headers: {
            'Content-Type': 'multipart/form-data',
        },
        data: this.files,
    })
    console.log(res)
},

上传/下载进度条

html

<!-- 选择文件 -->
<el-upload 
    :action="uploadFileReq" 
    ref="upload" 
    :on-change="handleChange" 
    :on-success="handleSuccess" 
    :on-progress="handleProgress" 
    :auto-upload="false" 
    :file-list="fileList" 
    :show-file-list="false" drag>
    <i class="el-icon-upload"></i>
    <div class="el-upload__text">将文件拖到此处，或<em>点击上传</em></div>
</el-upload>

<el-button type="primary" @click="sendClick">上传</el-button>

<el-button type="primary" @click="downloadFile(292,'test.txt')">下载</el-button>

<!-- 进度条 -->
<div v-if="elProgress" class="up_progress">
    <div class="text_con">{{progressText}}</div>
    <el-progress :percentage="progressPercent" :text-inside="true" :stroke-width="16" status="success"> </el-progress>
    <div class="cancel_btn">
        <el-button type="success" round @click="cancelUpload" v-if="!switchBtn">取消上传</el-button>
        <el-button type="success" round @click="cancelDownload" v-else>取消下载</el-button>
    </div>
</div>

js

keepFileList 用来备份选择的文件列表，因取消下载后文件列表会被清空，导致不能继续上传

new Vue({
    el: '#app',
    data: {
        progressText: '',
        progressPercent: 0,
        elProgress: false,
        switchBtn: true,
        fileList: [],
        keepFileList: [],    
    },
    methods: {
        // 文件操作
        handleChange(file, fileList) {
            console.log(fileList)
            this.keepFileList = fileList
        },
        // 上传
        sendClick() {
            console.log('开始上传')
            this.progressPercent = 0
            this.switchBtn = false
            this.$refs.upload.submit()
            this.progressText = '正在上传'
        },
        // 文件上传时
        handleProgress(event) {
            console.log(event)
            this.elProgress = true
            if (this.progressPercent < 99) {
                this.progressPercent = parseInt(event.percent)
            } else {
                this.progressText = '正在解析'
            }
        },
        // 上传成功
        handleSuccess(res) {
            console.log(res)
            if (res.success == 1) {
                this.progressPercent = 100
                this.progressText = '上传成功'
            } else {
                console.log('上传失败')
            }
            this.elProgress = false
        },
        // 取消上传
        cancelUpload() {
            this.$refs.upload.abort()
            this.$refs.upload.clearFiles()
            this.fileList = this.keepFileList.concat()
            this.fileList[0].status = 'ready'
            this.elProgress = false
            console.log('取消上传')
        },
        // 下载
        async downloadFile(id, fileName) {
            console.log('开始下载')
            this.progressPercent = 0
            this.switchBtn = true
            let _this = this
            const res = await axios({
                url: `${this.downloadFileReq}?id=${id}&downAre=0`,
                responseType: 'blob',
                onDownloadProgress: function (progressEvent) {
                    console.log(progressEvent)
                    if (progressEvent.lengthComputable) {
                        _this.elProgress = true
                        _this.progressText = '正在解析'
                        _this.progressPercent = parseInt((progressEvent.loaded / progressEvent.total) * 100)
                    }
                },
            })
            console.log(res)
            let blob = new Blob([res.data])
            let downloadElement = document.createElement('a')
            let href = window.URL.createObjectURL(blob) //创建下载的链接
            // 响应头里获取文件名，需要后端放行
            let filename1 = decodeURI(res.headers['content-disposition'].replace('attachment;filename=', ''))
            // let filename1 = res.headers['content-disposition'].replace('attachment;filename=', '')
            console.log(filename1)
            downloadElement.style.display = 'none'
            downloadElement.href = href
            downloadElement.download = filename1 //下载后文件名
            document.body.appendChild(downloadElement)
            downloadElement.click()
            document.body.removeChild(downloadElement) //下载完成移除元素
            window.URL.revokeObjectURL(href) //释放掉blob对象
            this.elProgress = false
            console.log('下载完成')
        },
        // 取消下载
        cancelDownload() {
            location.reload()
        },
    } 
})

 后端放行响应头代码

// 放行Content-disposition响应头
response.setHeader("Access-Control-Expose-Headers", "Content-disposition");

axios上传进度方式

// 文件操作
handleChange(file, fileList) {
    console.log(file)
    console.log(fileList)
    let formData = new FormData()
    formData.append('file', file.raw)
    this.files = formData
},
// 点击上传
async sendClick() {
    const { data: res } = await axios({
        method: 'post',
        url: this.uploadFileReq,
        headers: {
            'Content-Type': 'multipart/form-data',
        },
        data: this.files,
        onUploadProgress: function (progressEvent) {
                    console.log(progressEvent)
                    if (progressEvent.lengthComputable) {
                        _this.elProgress = true
                        _this.progressText = '正在上传'
                        _this.progressPercent = parseInt((progressEvent.loaded / progressEvent.total) * 100)
                    }
                },
    })
    console.log(res)
},

模拟上传进度(定时器)

data:{
    times: null,
    progressPercent: 0,
    elProgress: false,
},

method:{
    // 文件上传时
    handleProgress(event) {
        console.log(event)
        this.elProgress = true
        //使用定时器来制作进度条
        this.times = setInterval(() => {
            this.progressPercent++
            if (this.progressPercent > 90) {
                clearInterval(this.timer)
                this.times = null
            }
        }, 900)
    },
    // 上传成功
    handleSuccess(res) {
        console.log(res)
        if (res.success == 1) {
            this.progressPercent = 100
            this.progressText = '上传成功'
        } else {
            console.log('上传失败')
        }
        this.elProgress = false
    },
}

附赠

ajax上传

// html
<button onclick="download(292)">测试下载</button>

// js
<script>
    function load() {
        console.log('开始下载')
    }
    function closeLoad() {
        console.log('下载完成')
    }
    function download(id) {
        load()
        let url = `http://127.0.0.1/download?id=${id}`
        var xhr = new XMLHttpRequest()
        xhr.open('GET', url, true)
        xhr.responseType = 'blob'
        xhr.onload = function () {
            console.log(xhr)
            if (this.status === 200) {
                var blob = this.response
                if (navigator.msSaveBlob == null) {
                    let a = document.createElement('a')
                    let headerName = xhr.getResponseHeader('Content-disposition')
                    let fileName = decodeURIComponent(headerName).substring(20)
                    a.download = fileName
                    a.href = URL.createObjectURL(blob)
                    document.body.appendChild(a)
                    a.click()
                    URL.revokeObjectURL(a.href)
                    document.body.removeChild(a)
                } else {
                    navigator.msSaveBlob(blob, fileName)
                }
            }
            closeLoad()
        }
        xhr.send()
    }
</script>

获取文件方法

        // 选择文件
		handleChange(file, fileLists) {
			console.log(file);
			console.log(fileLists);
            // 获取文件对象
            console.log(file.raw)
			// 本地服务器路径
			console.log(URL.createObjectURL(file.raw));
			// 本地电脑路径
			console.log(document.getElementsByClassName("el-upload__input")[0].value); 
		}