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HarmonyOS App(JAVA)多线程任务分发器

打印时间，记录到编辑框textfield信息显示

同步分发，异步分发，异步延迟分发，分组任务分发，屏蔽任务分发，多次任务分发

参考代码注释

场景介绍

如果应用的业务逻辑比较复杂，可能需要创建多个线程来执行多个任务。这种情况下，代码复杂难以维护，任务与线程的交互也会更加繁杂。要解决此问题，开发者可以使用“TaskDispatcher”来分发不同的任务。

接口说明

TaskDispatcher是一个任务分发器，它是Ability分发任务的基本接口，隐藏任务所在线程的实现细节。

为保证应用有更好的响应性，我们需要设计任务的优先级。在UI线程上运行的任务默认以高优先级运行，如果某个任务无需等待结果，则可以用低优先级。

表1 线程优先级介绍

优先级	详细描述
HIGH	最高任务优先级，比默认优先级、低优先级的任务有更高的几率得到执行。
DEFAULT	默认任务优先级， 比低优先级的任务有更高的几率得到执行。
LOW	低任务优先级，比高优先级、默认优先级的任务有更低的几率得到执行。

TaskDispatcher具有多种实现，每种实现对应不同的任务分发器。在分发任务时可以指定任务的优先级，由同一个任务分发器分发出的任务具有相同的优先级。系统提供的任务分发器有GlobalTaskDispatcher、ParallelTaskDispatcher、SerialTaskDispatcher 、SpecTaskDispatcher。

• GlobalTaskDispatcher

  全局并发任务分发器，由Ability执行getGlobalTaskDispatcher()获取。适用于任务之间没有联系的情况。一个应用只有一个GlobalTaskDispatcher，它在程序结束时才被销毁。

  1. TaskDispatcher globalTaskDispatcher = getGlobalTaskDispatcher(TaskPriority.DEFAULT);
• ParallelTaskDispatcher

  并发任务分发器，由Ability执行createParallelTaskDispatcher()创建并返回。与GlobalTaskDispatcher不同的是，ParallelTaskDispatcher不具有全局唯一性，可以创建多个。开发者在创建或销毁dispatcher时，需要持有对应的对象引用 。

  1. String dispatcherName = "parallelTaskDispatcher";
  2. TaskDispatcher parallelTaskDispatcher = createParallelTaskDispatcher(dispatcherName, TaskPriority.DEFAULT);
• SerialTaskDispatcher

  串行任务分发器，由Ability执行createSerialTaskDispatcher()创建并返回。由该分发器分发的所有的任务都是按顺序执行，但是执行这些任务的线程并不是固定的。如果要执行并行任务，应使用ParallelTaskDispatcher或者GlobalTaskDispatcher，而不是创建多个SerialTaskDispatcher。如果任务之间没有依赖，应使用GlobalTaskDispatcher来实现。它的创建和销毁由开发者自己管理，开发者在使用期间需要持有该对象引用。

  1. String dispatcherName = "serialTaskDispatcher";
  2. TaskDispatcher serialTaskDispatcher = createSerialTaskDispatcher(dispatcherName, TaskPriority.DEFAULT);
• SpecTaskDispatcher

  专有任务分发器，绑定到专有线程上的任务分发器。目前已有的专有线程为UI线程，通过UITaskDispatcher进行任务分发。

  UITaskDispatcher：绑定到应用主线程的专有任务分发器， 由Ability执行getUITaskDispatcher()创建并返回。 由该分发器分发的所有的任务都是在主线程上按顺序执行，它在应用程序结束时被销毁。

  1. TaskDispatcher uiTaskDispatcher = getUITaskDispatcher();

<?xml version="1.0" encoding="utf-8"?>
<DirectionalLayoutxmlns:ohos="http://schemas.huawei.com/res/ohos"ohos:height="match_parent"ohos:width="match_parent"ohos:alignment="center"ohos:orientation="vertical"><Textohos:id="$+id:text_helloworld"ohos:height="match_content"ohos:width="match_content"ohos:background_element="$graphic:background_ability_main"ohos:layout_alignment="horizontal_center"ohos:text="$string:mainability_HelloWorld"ohos:text_size="40vp"/><Buttonohos:id="$+id:btn_tongbu"ohos:height="match_content"ohos:width="match_content"ohos:background_element="#EB0BF647"ohos:layout_alignment="horizontal_center"ohos:text="同步分发"ohos:text_size="40vp"/><Buttonohos:id="$+id:btn_yibu"ohos:height="match_content"ohos:width="match_content"ohos:background_element="#EB3D5DFC"ohos:layout_alignment="horizontal_center"ohos:text="异步分发"ohos:text_size="40vp"/><Buttonohos:id="$+id:btn_yibu_yanchi"ohos:height="match_content"ohos:width="match_content"ohos:background_element="#EB0BF647"ohos:layout_alignment="horizontal_center"ohos:text="异步延迟分发"ohos:text_size="40vp"/><Buttonohos:id="$+id:btn_fenzhu_task"ohos:height="match_content"ohos:width="match_content"ohos:background_element="#EB3D5DFC"ohos:layout_alignment="horizontal_center"ohos:text="分组任务分发"ohos:text_size="40vp"/><Buttonohos:id="$+id:btn_pingbi_task"ohos:height="match_content"ohos:width="match_content"ohos:background_element="#EB0BF647"ohos:layout_alignment="horizontal_center"ohos:text="屏蔽任务分发"ohos:text_size="40vp"/><Buttonohos:id="$+id:btn_duoci_task"ohos:height="match_content"ohos:width="match_content"ohos:background_element="#EB3D5DFC"ohos:layout_alignment="horizontal_center"ohos:text="多次任务分发"ohos:text_size="40vp"/><Textohos:id="$+id:text_label"ohos:height="match_content"ohos:width="match_content"ohos:background_element="$graphic:background_ability_main"ohos:layout_alignment="left"ohos:text="信息显示："ohos:multiple_lines="true"ohos:text_size="20vp"/><TextFieldohos:id="$+id:text_filed_info"ohos:height="300vp"ohos:background_element="#FC0A84EF"ohos:text="信息显示区域"ohos:width="350vp"ohos:hint=""ohos:margin="2vp"ohos:text_size="20vp"/><Clockohos:id="$+id:clock"ohos:height="match_content"ohos:width="match_content"ohos:background_element="#FF80EF66"ohos:layout_alignment="left"ohos:text_size="20vp"/></DirectionalLayout>

package com.example.myapplication.slice;import com.example.myapplication.ResourceTable;
import ohos.aafwk.ability.AbilitySlice;
import ohos.aafwk.content.Intent;
import ohos.agp.components.*;
import ohos.app.dispatcher.Group;
import ohos.app.dispatcher.TaskDispatcher;
import ohos.app.dispatcher.task.TaskPriority;
import ohos.hiviewdfx.HiLog;
import ohos.hiviewdfx.HiLogLabel;import java.util.function.Consumer;public class MainAbilitySlice extends AbilitySlice {static final HiLogLabel label = new HiLogLabel(HiLog.INFO,0x00101,"shanshui");TextField textField;Clock clock2;@Overridepublic void onStart(Intent intent) {super.onStart(intent);super.setUIContent(ResourceTable.Layout_ability_main);HiLog.info(label,  "hellocdtxw");HiLog.info(label,  "%{public}s World %d", "hellocdtxw", 3);HiLog.info(label,  "%{public}s World %d", "hellocdtxw", 3);System.out.println("hellocdtxw");Button btn_tongbu = (Button) findComponentById(ResourceTable.Id_btn_tongbu);textField = (TextField) findComponentById(ResourceTable.Id_text_filed_info);clock2 = (Clock) findComponentById(ResourceTable.Id_clock);clock2.setFormatIn24HourMode("yyyy-MM-dd HH:mm:ss");Button btn_yibu = (Button) findComponentById(ResourceTable.Id_btn_yibu);Button btn_delay = (Button) findComponentById(ResourceTable.Id_btn_yibu_yanchi);Button btn_group = (Button ) findComponentById(ResourceTable.Id_btn_fenzhu_task);Button btn_pingbi = (Button) findComponentById(ResourceTable.Id_btn_pingbi_task);Button btn_more_time = (Button) findComponentById(ResourceTable.Id_btn_duoci_task);btn_more_time.setClickedListener(new Component.ClickedListener() {@Overridepublic void onClick(Component component) {MoreTimesTask();}});btn_delay.setClickedListener(new Component.ClickedListener() {@Overridepublic void onClick(Component component) {YibuDealyTask();}});btn_group.setClickedListener(new Component.ClickedListener() {@Overridepublic void onClick(Component component) {YibuGroupTask();}});btn_pingbi.setClickedListener(new Component.ClickedListener() {@Overridepublic void onClick(Component component) {PingBiTask();}});btn_yibu.setClickedListener(new Component.ClickedListener() {@Overridepublic void onClick(Component component) {YibuTask();}});btn_tongbu.setClickedListener(new Component.ClickedListener() {@Overridepublic void onClick(Component component) {HiLog.info(label,  "hellocdtxw");HiLog.info(label,  "%{public}s World %d", "hellocdtxw", 3);HiLog.info(label,  "%{public}s World %d", "hellocdtxw", 3);System.out.println("hellocdtxw");TongBuTask();}});}/*同步分发任务,多线程，阻塞模式，会卡主界面，不常用*/public void TongBuTask(){TaskDispatcher dispatcher =getGlobalTaskDispatcher(TaskPriority.DEFAULT);String time_str = clock2.getText();textField.append(time_str+":同步线程启动\n");dispatcher.syncDispatch(new Runnable() {@Overridepublic void run() {try{//getUITaskDispatcher().syncDispatch(()->{// textField.append(clock2.getText()+":task1:"+Thread.currentThread().getName());//});Thread.sleep(1000);}catch (InterruptedException e){//getUITaskDispatcher().syncDispatch(()->{//  textField.append(clock2.getText()+"任务失败");// });}}});dispatcher.syncDispatch(new Runnable() {@Overridepublic void run() {try{//getUITaskDispatcher().syncDispatch(()->{// textField.append(clock2.getText()+":task1:"+Thread.currentThread().getName());//});Thread.sleep(1000);}catch (InterruptedException e){//getUITaskDispatcher().syncDispatch(()->{//  textField.append(clock2.getText()+"任务失败");// });}}});dispatcher.syncDispatch(new Runnable() {@Overridepublic void run() {try{//getUITaskDispatcher().syncDispatch(()->{// textField.append(clock2.getText()+":task1:"+Thread.currentThread().getName());//});Thread.sleep(1000);}catch (InterruptedException e){//getUITaskDispatcher().syncDispatch(()->{//  textField.append(clock2.getText()+"任务失败");// });}}});}//异步模式，鸿蒙系统app多线程public  void YibuTask(){TaskDispatcher dispatcher =getGlobalTaskDispatcher(TaskPriority.DEFAULT);String time_str = clock2.getText();textField.append(time_str+":异步线程启动\n");dispatcher.asyncDispatch(new Runnable() {@Overridepublic void run() {try{getUITaskDispatcher().asyncDispatch(()->{textField.append(clock2.getText()+":task1:"+Thread.currentThread().getName()+"\n");});Thread.sleep(1000);}catch (InterruptedException e){getUITaskDispatcher().asyncDispatch(()->{textField.append(clock2.getText()+"任务失败");});}}});dispatcher.asyncDispatch(new Runnable() {@Overridepublic void run() {try{getUITaskDispatcher().asyncDispatch(()->{textField.append(clock2.getText()+":task2:"+Thread.currentThread().getName()+"\n");});Thread.sleep(1000);}catch (InterruptedException e){getUITaskDispatcher().asyncDispatch(()->{textField.append(clock2.getText()+"任务失败");});}}});dispatcher.asyncDispatch(new Runnable() {@Overridepublic void run() {try{getUITaskDispatcher().asyncDispatch(()->{textField.append(clock2.getText()+":task3:"+Thread.currentThread().getName()+"\n");});Thread.sleep(1000);}catch (InterruptedException e){getUITaskDispatcher().asyncDispatch(()->{textField.append(clock2.getText()+"任务失败");});}}});}//异步延迟任务分发public  void YibuDealyTask(){TaskDispatcher dispatcher =getGlobalTaskDispatcher(TaskPriority.DEFAULT);String time_str = clock2.getText();dispatcher.delayDispatch(()-> {getUITaskDispatcher().asyncDispatch(()->{textField.append(time_str+":异步延迟任务分发线程启动\n");});},1000);}//异步分组任务分发public  void YibuGroupTask(){TaskDispatcher dispatcher =getGlobalTaskDispatcher(TaskPriority.DEFAULT);String time_str = clock2.getText();Group group = dispatcher.createDispatchGroup();dispatcher.asyncGroupDispatch(group, new Runnable() {@Overridepublic void run() {HiLog.info(label,  "%{public}s World %d", "hellocdtxw", 3);}});dispatcher.asyncGroupDispatch(group, new Runnable() {@Overridepublic void run() {HiLog.info(label,  "%{public}s World %d", "hellocdtxw", 3);}});dispatcher.asyncGroupDispatch(group, new Runnable() {@Overridepublic void run() {HiLog.info(label,  "%{public}s World %d", "hellocdtxw", 3);}});}//屏蔽任务分发public void PingBiTask(){TaskDispatcher dispatcher =createParallelTaskDispatcher("Dispatcher",TaskPriority.DEFAULT);Group group = dispatcher.createDispatchGroup();dispatcher.asyncGroupDispatch(group,()->{try{Thread.sleep(1000);HiLog.info(label,  "%{public}s World %d", "hellocdtxw", 3);}catch (InterruptedException ex){}});dispatcher.asyncGroupDispatch(group,()->{try{Thread.sleep(1000);HiLog.info(label,  "%{public}s World %d", "hellocdtxw", 3);}catch (InterruptedException ex){}});dispatcher.asyncDispatchBarrier(()->{try{Thread.sleep(1000);getUITaskDispatcher().asyncDispatch(()->{textField.append(clock2.getText()+":屏蔽任务分发线程启动\n");});}catch (InterruptedException ex){}});dispatcher.asyncGroupDispatch(group,()->{try{Thread.sleep(1000);HiLog.info(label,  "%{public}s World %d", "hellocdtxw", 3);}catch (InterruptedException ex){}});dispatcher.asyncGroupDispatch(group,()->{try{Thread.sleep(1000);HiLog.info(label,  "%{public}s World %d", "hellocdtxw", 3);}catch (InterruptedException ex){}});dispatcher.asyncDispatchBarrier(()->{try{Thread.sleep(1000);getUITaskDispatcher().asyncDispatch(()->{textField.append(clock2.getText()+":屏蔽任务分发线程启动\n");});}catch (InterruptedException ex){}});}public void MoreTimesTask(){getGlobalTaskDispatcher(TaskPriority.DEFAULT).applyDispatch(new Consumer<Long>() {@Overridepublic void accept(Long aLong) {getUITaskDispatcher().asyncDispatch(()->{textField.append(clock2.getText()+":多次任务分发线程启动"+aLong.toString()+"\n");});}},10); //执行10次}@Overridepublic void onActive() {super.onActive();}@Overridepublic void onForeground(Intent intent) {super.onForeground(intent);}
}