The trial - which has been criticised for potentially criminalising 12-year-olds - will take place over 14 months.
It is due to start from 6 April.
The Home Office said the orders were intended to be "preventative rather than punitive" in a bid to encourage people to change their behaviour and avoid being drawn into knife crime.
Commander Jane Connors, from the Metropolitan Police Service, said the orders would be a "valuable tactic in preventing violence on the streets of London".
For full article https://www.bbc.co.uk/news/uk-51733754