1# 多级Worker间高性能消息通信 2<!--Kit: ArkTS--> 3<!--Subsystem: CommonLibrary--> 4<!--Owner: @lijiamin2025--> 5<!--Designer: @weng-changcheng--> 6<!--Tester: @kirl75; @zsw_zhushiwei--> 7<!--Adviser: @ge-yafang--> 8 9多级[Worker](worker-introduction.md)（即通过父Worker创建子Worker的机制形成层级线程关系）间通信是一种常见的需求，由于Worker线程生命周期由用户自行管理，因此需要注意多级Worker生命周期的正确管理，建议开发者确保销毁父Worker前先销毁所有子Worker。 10 11本文介绍如何在多级Worker间实现高性能消息通信。高性能消息通信的关键在于[Sendable对象](arkts-sendable.md)，结合[postMessageWithSharedSendable接口](../reference/apis-arkts/js-apis-worker.md#postmessagewithsharedsendable12)，可以实现线程间高性能的对象传递。例如，在数据克隆场景中，假设有一个父Worker和两个子Worker。父Worker负责创建子Worker，并向子Worker发送数据克隆任务。子Worker接收任务并执行数据克隆操作，完成后将克隆结果返回给父Worker。 12 131. 准备一个Sendable类CopyEntry，封装克隆任务数据。 14 15 ```ts 16 // CopyEntry.ets 17 @Sendable 18 export class CopyEntry { 19 // 克隆类型 20 type: string; 21 // 文件路径 22 filePath: string; 23 constructor(type: string, filePath: string) { 24 this.type = type; 25 this.filePath = filePath; 26 } 27 } 28 ``` 29 302. 创建两个Worker文件，DevEco Studio支持一键生成Worker，在对应的{moduleName}目录下任意位置，单击鼠标右键 > New > Worker，即可自动生成Worker的模板文件及配置信息。本文以创建“ParentWorker”（父Worker）和“ChildWorker”（子Worker）为例。父Worker负责分发克隆任务并判断任务全部完成后关闭子Worker与父Worker；子Worker负责接收任务并执行数据克隆操作，并在任务完成后通知父Worker。 31 32 ```ts 33 // ParentWorker.ets 34 import { ErrorEvent, MessageEvents, ThreadWorkerGlobalScope, worker, collections, ArkTSUtils } from '@kit.ArkTS' 35 import { CopyEntry } from './CopyEntry' 36 37 const workerPort: ThreadWorkerGlobalScope = worker.workerPort; 38 39 // 计算worker1的任务数量 40 let count1 = 0; 41 // 计算worker2的任务数量 42 let count2 = 0; 43 // 计算总任务数量 44 let sum = 0; 45 // 异步锁 46 const asyncLock = new ArkTSUtils.locks.AsyncLock(); 47 // 创建子Worker 48 const copyWorker1 = new worker.ThreadWorker('entry/ets/pages/ChildWorker.ets'); 49 const copyWorker2 = new worker.ThreadWorker('entry/ets/pages/ChildWorker.ets'); 50 51 workerPort.onmessage = (e : MessageEvents) => { 52 let array = e.data as collections.Array<CopyEntry>; 53 sum = array.length; 54 for (let i = 0; i < array.length; i++) { 55 let entry = array[i]; 56 if (entry.type === 'copy1') { 57 count1++; 58 // 如果是copy1类型，则将数据传递给 copyWorker1 59 copyWorker1.postMessageWithSharedSendable(entry); 60 } else if (entry.type === 'copy2') { 61 count2++; 62 // 如果是copy2类型，则将数据传递给 copyWorker2 63 copyWorker2.postMessageWithSharedSendable(entry); 64 } 65 } 66 } 67 68 copyWorker1.onmessage = async (e : MessageEvents) => { 69 console.info('copyWorker1 onmessage:' + e.data); 70 await asyncLock.lockAsync(() => { 71 count1--; 72 if (count1 == 0) { 73 // 如果copyWorker1的任务全部完成，则关闭copyWorker1 74 console.info('copyWorker1 close'); 75 copyWorker1.terminate(); 76 } 77 sum--; 78 if (sum == 0) { 79 // 如果所有任务全部完成，则关闭父Worker 80 workerPort.close(); 81 } 82 }) 83 } 84 85 copyWorker2.onmessage = async (e : MessageEvents) => { 86 console.info('copyWorker2 onmessage:' + e.data); 87 await asyncLock.lockAsync(() => { 88 count2--; 89 sum--; 90 if (count2 == 0) { 91 // 如果copyWorker2的任务全部完成，则关闭copyWorker2 92 console.info('copyWorker2 close') 93 copyWorker2.terminate(); 94 } 95 if (sum == 0) { 96 // 如果所有任务全部完成，则关闭父Worker 97 workerPort.close(); 98 } 99 }) 100 } 101 102 workerPort.onmessageerror = (e : MessageEvents) => { 103 console.error('onmessageerror:' + e.data); 104 } 105 106 workerPort.onerror = (e : ErrorEvent) => { 107 console.error('onerror:' + e.message); 108 } 109 ``` 110 ```ts 111 // ChildWorker.ets 112 import { ErrorEvent, MessageEvents, ThreadWorkerGlobalScope, worker} from '@kit.ArkTS' 113 import { CopyEntry } from './CopyEntry' 114 115 const workerPort: ThreadWorkerGlobalScope = worker.workerPort; 116 117 workerPort.onmessage = (e : MessageEvents) => { 118 let data = e.data as CopyEntry; 119 // 中间copy操作省略 120 console.info(data.filePath); 121 workerPort.postMessageWithSharedSendable("done"); 122 } 123 124 workerPort.onmessageerror = (e : MessageEvents) => { 125 console.error('onmessageerror:' + e.data); 126 } 127 128 workerPort.onerror = (e : ErrorEvent) => { 129 console.error('onerror:' + e.message); 130 } 131 ``` 132 1333. 在UI主线程页面，创建父Worker并准备克隆任务所需的数据，准备完成后将数据发送给父Worker。 134 135 ```ts 136 // Index.ets 137 import { worker, collections } from '@kit.ArkTS'; 138 import { CopyEntry } from './CopyEntry' 139 140 function promiseCase() { 141 let p: Promise<void> = new Promise<void>((resolve: Function, reject: Function) => { 142 setTimeout(() => { 143 resolve(); 144 }, 100); 145 }); 146 return p; 147 } 148 149 async function postMessageTest() { 150 let ss = new worker.ThreadWorker("entry/ets/pages/ParentWorker.ets"); 151 let isTerminate = false; 152 ss.onexit = () => { 153 isTerminate = true; 154 } 155 let array = new collections.Array<CopyEntry>(); 156 // 准备数据 157 for (let i = 0; i < 4; i++) { 158 if (i % 2 == 0) { 159 array.push(new CopyEntry("copy1", "file://copy1.txt")); 160 } else { 161 array.push(new CopyEntry("copy2", "file://copy2.txt")); 162 } 163 } 164 // 给Worker线程发送消息 165 ss.postMessageWithSharedSendable(array); 166 while (!isTerminate) { 167 await promiseCase(); 168 } 169 console.info("Worker线程已退出"); 170 } 171 172 @Entry 173 @Component 174 struct Index { 175 @State message: string = 'Hello World'; 176 build() { 177 Row() { 178 Column() { 179 Text(this.message) 180 .fontSize(50) 181 .fontWeight(FontWeight.Bold) 182 .onClick(() => { 183 postMessageTest(); 184 }) 185 } 186 .width('100%') 187 } 188 .height('100%') 189 } 190 } 191 ```