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这篇文章主要介绍“React和Vue怎么实现文件下载进度条”的相关知识，小编通过实际案例向大家展示操作过程，操作方法简单快捷，实用性强，希望这篇“React和Vue怎么实现文件下载进度条”文章能帮助大家解决问题。
下载服务端大文件资源过慢，页面没有任何显示，体验太差。因此需增加进度条优化显示
发送异步HTTP请求，监听onprogress事件，读取已下载的资源和资源总大小得到下载百分比
在资源请求完成后，将文件内容转为blob，并通过a标签将文件通过浏览器下载下来
前提：通过create-react-app创建的react项目
将静态资源文件放到public文件夹下，这样启动项目后，可直接通过http://localhost:3000/1.pdf 的方式访问到静态资源。在实际工作中，肯定是直接访问服务器上的资源
新建useDownload.ts
import { useCallback, useRef, useState } from 'react';
interface Options {
fileName: string; //下载的文件名
onCompleted?: () => void; //请求完成的回调方法
onError?: (error: Error) => void; //请求失败的回调方法
}
interface FileDownReturn {
download: () => void; //下载
cancel: () => void; //取消
progress: number; //下载进度百分比
isDownloading: boolean; //是否下载中
}
export default function useFileDown(url: string, options: Options): FileDownReturn {
const { fileName, onCompleted, onError } = options;
const [progress, setProgress] = useState(0);
const [isDownloading, setIsDownloading] = useState(false);
const xhrRef = useRef<XMLHttpRequest | null>(null);
const download = useCallback(() => {
const xhr = (xhrRef.current = new XMLHttpRequest());
xhr.open('GET', url); //默认异步请求
xhr.responseType = 'blob';
xhr.onprogress = (e) => {
//判断资源长度是否可计算
if (e.lengthComputable) {
const percent = Math.floor((e.loaded / e.total) * 100);
setProgress(percent);
}
};
xhr.onload = () => {
if (xhr.status === 200) {
//请求资源完成，将文件内容转为blob
const blob = new Blob([xhr.response], { type: 'application/octet-stream' });
//通过a标签将资源下载
const link = document.createElement('a');
link.href = window.URL.createObjectURL(blob);
link.download = decodeURIComponent(fileName);
link.click();
window.URL.revokeObjectURL(link.href);
onCompleted && onCompleted();
} else {
onError && onError(new Error('下载失败'));
}
setIsDownloading(false);
};
xhr.onerror = () => {
onError && onError(new Error('下载失败'));
setIsDownloading(false);
};
xhrRef.current.send(); //发送请求
setProgress(0); //每次发送时将进度重置为0
setIsDownloading(true);
}, [fileName, onCompleted, onError, url]);
const cancel = useCallback(() => {
xhrRef.current?.abort(); //取消请求
setIsDownloading(false);
}, [xhrRef]);
return {
download,
cancel,
progress,
isDownloading,
};
}import { memo } from 'react';
import useFileDown from './useDownload';
const list = [
{
fileName: '城市发展史起.pdf',
url: ' http://localhost:3000/1.pdf',
type: 'pdf',
},
{
fileName: '表格.xlsx',
url: 'http://localhost:3000/表格.xlsx',
type: 'xlsx',
},
{
fileName: '报告.doc',
url: 'http://localhost:3000/报告.doc',
type: 'doc',
},
];
interface Options {
url: string;
fileName: string;
}
const Item = memo(({ url, fileName }: Options) => {
//每项都需拥有一个属于自己的 useFileDown hook
const { download, cancel, progress, isDownloading } = useFileDown(url, { fileName });
return (
<div>
<span style={{ cursor: 'pointer' }} onClick={download}>
{fileName}
</span>
{isDownloading ? (
<span>
{`下载中：${progress}`}
<button onClick={cancel}>取消下载</button>
</span>
) : (
''
)}
</div>
);
});
const Download = () => {
return (
<div>
{list.map((item, index) => (
<Item url={item.url} fileName={item.fileName} key={index} />
))}
</div>
);
};
export default Download;前提：通过vite创建的vue项目
将静态资源文件放到public文件夹下，这样启动项目后，可直接通过http://127.0.0.1:5173/1.pdf 的方式访问到静态资源
新建hooks/useDownload.ts（新建hooks文件夹）
import { ref } from "vue";
export interface Options {
fileName: string;
onCompleted?: () => void; //请求完成的回调方法
onError?: (error: Error) => void; //请求失败的回调方法
}
export interface FileDownReturn {
download: () => void; //下载
cancel: () => void; //取消
progress: number; //下载进度百分比
isDownloading: boolean; //是否下载中
}
export default function useFileDown(
url: string,
options: Options
): FileDownReturn {
const { fileName, onCompleted, onError } = options;
const progress = ref(0);
const isDownloading = ref(false);
const xhrRef = ref<XMLHttpRequest | null>(null);
const download = () => {
const xhr = (xhrRef.value = new XMLHttpRequest());
xhr.open("GET", url); //默认异步请求
xhr.responseType = "blob";
xhr.onprogress = (e) => {
//判断资源长度是否可计算
if (e.lengthComputable) {
const percent = Math.floor((e.loaded / e.total) * 100);
progress.value = percent;
}
};
xhr.onload = () => {
if (xhr.status === 200) {
//请求资源完成，将文件内容转为blob
const blob = new Blob([xhr.response], {
type: "application/octet-stream",
});
//通过a标签将资源下载
const link = document.createElement("a");
link.href = window.URL.createObjectURL(blob);
link.download = decodeURIComponent(fileName);
link.click();
window.URL.revokeObjectURL(link.href);
onCompleted && onCompleted();
} else {
onError && onError(new Error("下载失败"));
}
isDownloading.value = false;
};
xhr.onerror = () => {
onError && onError(new Error("下载失败"));
isDownloading.value = false;
};
xhrRef.value.send(); //发送请求
progress.value = 0; //每次发送时将进度重置为0
isDownloading.value = true;
};
const cancel = () => {
xhrRef.value?.abort(); //取消请求
isDownloading.value = false;
};
return {
download,
cancel,
progress,
isDownloading,
};
}修改App.vue
<script setup lang="ts">
import Item from "./components/Item.vue";
const list = [
{
fileName: "城市发展史起.pdf",
url: " http://127.0.0.1:5173/1.pdf",
type: "pdf",
},
{
fileName: "表格.xlsx",
url: "http://127.0.0.1:5173/表格.xlsx",
type: "xlsx",
},
{
fileName: "报告.doc",
url: "http://127.0.0.1:5173/报告.doc",
type: "doc",
},
];
</script>
<template>
<div>
<div v-for="(item, index) in list" :key="index">
<Item :url="item.url" :fileName="item.fileName"<script setup lang="ts">
import useFileDown from "../hooks/useDownload.ts";
const props = defineProps<{ url: string; fileName: string }>();
const { url, fileName } = props;
const { download, cancel, progress, isDownloading } = useFileDown(url, {
fileName,
});
</script>
<template>
<div>
<span @click="download">
{{ fileName }}
</span>
<span v-if="isDownloading">
下载中:{{ progress }} <button @click="cancel">取消下载</button></span
>
</div>
</template> />
</div>
</div>
</template>新建components/Item.vue
<script setup lang="ts">
import useFileDown from "../hooks/useDownload.ts";
const props = defineProps<{ url: string; fileName: string }>();
const { url, fileName } = props;
const { download, cancel, progress, isDownloading } = useFileDown(url, {
fileName,
});
</script>
<template>
<div>
<span @click="download">
{{ fileName }}
</span>
<span v-if="isDownloading">
下载中:{{ progress }} <button @click="cancel">取消下载</button></span
>
</div>
</template>解决办法：让后端加上就行
开启gzip之后服务器默认开启文件分块编码（响应头返回Transfer-Encoding: chunked）。分块编码把「报文」分割成若干个大小已知的块，块之间是紧挨着发送的。采用这种传输方式进行响应时，不会传Content-Length这个首部信息，即使带上了也是不准确的
分别为gzip压缩，分块编码：
例如有个877k大小的js文件，网络请求的大小为247k。但是打印的e.loaded最终返回的是877k
解决方法：后端把文件大小存储到其他字段，比如：header['x-content-length']
关于“React和Vue怎么实现文件下载进度条”的内容就介绍到这里了，感谢大家的阅读。如果想了解更多行业相关的知识，可以关注亿速云行业资讯频道，小编每天都会为大家更新不同的知识点。
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