onWindowStageCreate(windowStage: window.WindowStage) {
// Main window is created, set main page for this ability
hilog.info(0x0000, 'testTag', '%{public}s', 'Ability 
onWindowStageCreate');
globalThis.abilityContext = this.context
//用全局对象获取context类的接口
globalThis.context = this.context
...
}

import fs from '@ohos.file.fs';
@Entry
@Component
struct Index {
@State message: string = 'rawfile_copy_to_sandbox'
//沙箱路径
dir:string = globalThis.abilityContext.filesDir + "/";
//从rawfile中读取input.txt文件，在log中显示
private async readfile_from_rawfile() {
try {
let uint8Array = await 
globalThis.context.resourceManager.getRawFileContent('rawfile/input.txt');
let str = String.fromCharCode.apply(null, new 
Uint8Array(uint8Array.buffer));
console.info("[rawfile_copy_to_sandbox] 
———————————————————————————————————————————————————————");
console.info("[rawfile_copy_to_sandbox] rawfile中的input.txt内容为" + str);
} catch (error) {
console.info("[rawfile_copy_to_sandbox] 
———————————————————————————————————————————————————————");
console.info("[rawfile_copy_to_sandbox] rawfile中的input.txt内容读取失败" + 
error);
}
}
//用来拷贝rawfile文件中的input.txt到应用沙箱目录下
private async copy_rawfile__to_sandbox() {
try {
let file = this.dir+"input.txt";
let sss = fs.createStreamSync(file, "w");//没有会创建一个空的input.txt
sss.closeSync();
//获取rawfile下input.txt
globalThis.context.resourceManager.getRawFileDescriptor('rawfile/input.txt',(error, 
value) => {
if (error != null) { //getRawFileDescriptor运行失败
console.info("[rawfile_copy_to_sandbox] 
———————————————————————————————————————————————————————");
console.log("[rawfile_copy_to_sandbox] getRawFileDescriptor api 运行失败: 
${error.code}, message: ${error.message}.");
console.log("[rawfile_copy_to_sandbox] 未能成功将rawfile下的input.txt文件拷贝到应用沙箱下 
");
} else { //getRawFileDescriptor运行成功
let fd = value.fd;
fs.copyFileSync(fd, file);
console.info("[rawfile_copy_to_sandbox] 
———————————————————————————————————————————————————————");
console.log("[rawfile_copy_to_sandbox] getRawFileDescriptor api 运行成功");
console.log("[rawfile_copy_to_sandbox] 成功将rawfile下的input.txt文件拷贝到应用沙箱下");
}
});
} catch (error) {
console.info("[rawfile_copy_to_sandbox] 
———————————————————————————————————————————————————————");
console.info("[rawfile_copy_to_sandbox] getRawFileDescriptor api 运行失败" + 
error);
console.log("[rawfile_copy_to_sandbox] 
未能成功将rawfile下的input.txt文件拷贝到应用沙箱下");
}
}
build() {
Row() {
Column() {
Button(this.message)
.fontSize(25)
.margin({top:0})
.fontWeight(FontWeight.Normal)
.backgroundColor(Color.Green) //设置按钮颜色
.onClick(() => {
console.info("[rawfile_copy_to_sandbox] 沙箱路径是"+ this.dir);
//用来复制rawfile文件中的input.txt到沙箱目录下
//调用的是私有的自定义的copy_rawfile__to_sandbox方法
this.copy_rawfile__to_sandbox();
this.readfile_from_rawfile();
})
}
.width('100%')
}
.height('100%')
}
}