鸿蒙开发系列（HarmonyOS）通过Request部件下载文件到本地场景实践 - qidao123.com技术社区-IT企服评测·应用市场

"requestPermissions": [
{
"name": "ohos.permission.INTERNET"
}
]

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import http from '@ohos.net.http';
import util from '@ohos.util';
import fs from '@ohos.file.fs';
import request from '@ohos.request';
import picker from '@ohos.file.picker';
@Entry
@Component
struct Index {
//连接、通讯历史记录
@State msgHistory: string = ''
//首页地址
@State downloadUrl: string = "http://192.168.100.101:8081/download?filename=demo.txt"
//登录地址
@State loginUrl: string = "http://192.168.100.101:8081/auth"
//用户名
@State loginName: string = "zhanglei"
//密码
@State passwd: string = "cangjie"
//下载到本地的路径
@State localFilePath: string = ""
scroller: Scroller = new Scroller()
sessionId: string = ""
build() {
Row() {
Column() {
Text("Request下载示例")
.fontSize(14)
.fontWeight(FontWeight.Bold)
.width('100%')
.textAlign(TextAlign.Center)
.padding(10)
Flex({ justifyContent: FlexAlign.Start, alignItems: ItemAlign.Center }) {
Text("用户名：")
.fontSize(14)
.width(80)
.flexGrow(0)
TextInput({ text: this.loginName })
.onChange((value) => {
this.loginName = value
})
.width(110)
.fontSize(11)
.flexGrow(1)
Text("密码：")
.fontSize(14)
.width(60)
.flexGrow(0)
TextInput({ text: this.passwd })
.onChange((value) => {
this.passwd = value
})
.type(InputType.Password)
.width(100)
.fontSize(11)
.flexGrow(1)
}
.width('100%')
.padding(10)
Flex({ justifyContent: FlexAlign.Start, alignItems: ItemAlign.Center }) {
Text("登录地址：")
.fontSize(14)
.width(80)
.flexGrow(0)
TextInput({ text: this.loginUrl })
.onChange((value) => {
this.loginUrl = value
})
.width(100)
.fontSize(11)
.flexGrow(1)
Button("登录")
.onClick(() => {
this.login()
})
.width(70)
.fontSize(14)
.flexGrow(0)
}
.width('100%')
.padding(10)
Flex({ justifyContent: FlexAlign.Start, alignItems: ItemAlign.Center }) {
Text("文件地址：")
.fontSize(14)
.width(80)
.flexGrow(0)
TextInput({ text: this.downloadUrl })
.onChange((value) => {
this.downloadUrl = value
})
.width(110)
.fontSize(11)
.flexGrow(1)
Button("下载")
.onClick(() => {
this.downloadFile()
})
.width(70)
.fontSize(14)
.flexGrow(0)
}
.width('100%')
.padding(10)
Flex({ justifyContent: FlexAlign.Start, alignItems: ItemAlign.Center }) {
Text("保存位置：")
.fontSize(14)
.width(80)
.flexGrow(0)
TextInput({ text: this.localFilePath })
.width(110)
.fontSize(11)
.flexGrow(1)
}
.width('100%')
.padding(10)
Scroll(this.scroller) {
Text(this.msgHistory)
.textAlign(TextAlign.Start)
.padding(10)
.width('100%')
.backgroundColor(0xeeeeee)
}
.align(Alignment.Top)
.backgroundColor(0xeeeeee)
.height(300)
.flexGrow(1)
.scrollable(ScrollDirection.Vertical)
.scrollBar(BarState.On)
.scrollBarWidth(20)
}
.width('100%')
.justifyContent(FlexAlign.Start)
.height('100%')
}
.height('100%')
}
//下载文件
downloadFile() {
this.localFilePath = getContext(this).tempDir + "/demo.txt"
//文件如果已经存在，就删除
if (fs.accessSync(this.localFilePath)) {
fs.unlink(this.localFilePath)
}
let cfg: request.DownloadConfig = {
url: this.downloadUrl,
header: {
'Accept-Encoding': 'gzip, deflate, br',
'Accept-Language': 'zh-CN,zh;q=0.9',
//这一步很关键，把登录成功后的cookie传递过去
'Cookie': 'sessionid=' + this.sessionId,
'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36',
},
filePath: this.localFilePath }
let downloadTask: request.DownloadTask;
try {
request.downloadFile(getContext(this), cfg
, (err, data) => {
if (err) {
console.error('Failed to request the download. Cause: ' + JSON.stringify(err));
return;
}
downloadTask = data;
downloadTask.on("progress", (size, tot) => {
this.msgHistory += `下载进度：${size}/${tot}\r\n`
})
downloadTask.on("complete", () => {
this.msgHistory += "下载完成\r\n"
//读取文件内容并显示
this.showFileContent(this.localFilePath)
})
});
} catch (err) {
this.msgHistory += 'err.code : ' + err.code + ', err.message : ' + err.message;
}
}
//显示指定文件的内容
showFileContent(filePath: string) {
let content = fs.readTextSync(filePath)
this.msgHistory += "文件内容：" + content + "\r\n"
}
//模拟登录
login() {
//http请求对象
let httpRequest = http.createHttp();
//请求的登录名和密码参数
let params = "username=" + this.loginName + "&password=" + this.passwd
let opt: http.HttpRequestOptions = {
method: http.RequestMethod.POST,
extraData: params,
header: { 'Content-Type': 'application/x-www-form-urlencoded' },
expectDataType: http.HttpDataType.STRING
}
httpRequest.request(this.loginUrl, opt)
.then((resp) => {
this.msgHistory += "响应码：" + resp.responseCode + "\r\n"
//返回的首部信息中，cookie的格式为：
// set-cookie: sessionid=19837d50s270ms999us100ns; Max-Age=1800; Path=/
//这里需要记录下sessionid，作为下次提交时的cookie信息
let cookies: string = resp.header["set-cookie"]
this.sessionId = cookies.split(";")[0].split("=")[1]
this.msgHistory += "sessionId：" + this.sessionId + "\r\n"
this.msgHistory += "登录成功\r\n"
})
.catch((e) => {
this.msgHistory += "登录失败：" + e.message + "\r\n"
})
}
}

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let cfg: request.DownloadConfig = {
url: this.downloadUrl,
header: {
'Accept-Encoding': 'gzip, deflate, br',
'Accept-Language': 'zh-CN,zh;q=0.9',
//这一步很关键，把登录成功后的cookie传递过去
'Cookie': 'sessionid=' + this.sessionId,
'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36',
},
filePath: this.localFilePath }

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this.localFilePath = getContext(this).tempDir + "/demo.txt"
//文件如果已经存在，就删除
if (fs.accessSync(this.localFilePath)) {
fs.unlink(this.localFilePath)
}

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