今天碰到空路由和空路由跳转无效的坑，经过折腾发现问题，发现原来是在app.module中需要先引入子路由，再引入根路由，代码：
根路由：
constroutes: Routes = [{
path:'',
redirectTo:'approval',
pathMatch:'full',
},{
path:'approval',
component: ApprovalComponent
}];
子路由：
constroutes: Routes = [{
path:'approval',
component: ApprovalComponent,
children: [{
path:'',
redirectTo:'list',
pathMatch:'full'
},{
path:'list',
component: ApprovalListComponent
}]
}];
AppModule.ts (ApprovalModule中导入了子路由)
@NgModule({
imports: [
AppRoutingModule,
ApprovalModule,ApprovalModule,
AppRoutingModule
],
bootstrap: [AppComponent]
})
export classAppModule { }
