创建ServiceAbility

1. 创建ServiceAbility。

   重写ServiceAbility的生命周期方法，添加其他Ability请求与ServiceAbility交互时的处理方法。

     import Want from '@ohos.app.ability.Want';
     import rpc from "@ohos.rpc"
     
     class FirstServiceAbilityStub extends rpc.RemoteObject {
       constructor(des: string) {
         super(des);
       }
     }
     
     class ServiceAbility {
       onStart() {
         console.info('ServiceAbility onStart')
       }
       onStop() {
         console.info('ServiceAbility onStop')
       }
       onCommand(want: Want, startId: number) {
         console.info('ServiceAbility onCommand')
       }
       onConnect(want: Want) {
         console.info('ServiceAbility onConnect' + want)
         return new FirstServiceAbilityStub('test')
       }
       onDisconnect(want: Want) {
         console.info('ServiceAbility onDisconnect' + want)
       }
     }
   
     export default new ServiceAbility()
   

2. 注册ServiceAbility。

   ServiceAbility需要在应用配置文件config.json中进行注册，注册类型type需要设置为service。"visible"属性表示ServiceAbility是否可以被其他应用调用，true表示可以被其他应用调用，false表示不能被其他应用调用（仅应用内可以调用）。若ServiceAbility需要被其他应用调用，注册ServiceAbility时需要设置"visible"为true，同时需要设置支持关联启动。ServiceAbility的启动规则详见组件启动规则章节。

        {
          "module": {
            "abilities": [
              {
                "name": ".ServiceAbility",
                "srcLanguage": "ets",
                "srcPath": "ServiceAbility",
                "icon": "$media:icon",
                "description": "hap sample empty service",
                "type": "service",
                "visible": true
              }
            ]
          }
        }