Filter an object list based on Integerlist [closed]

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I have a class like

class Employee
  String id
  String name

I want to filter out the list of employees based on the list of deptId which is an integer list

Employee emp1 = new Employee("1","Ally");
Employee emp2 = new Employee("2","Billy");
ArrayList<Employee> employeeList = Arrays.asList(emp1,emp2);
ArrayList<Integer> ids = Arrays.asList(2);

What I have written is

List<Employee> filteredList = employeeList.stream()
  .filter(employee -> ids.contains(employee.getId()))
  .collect(Collectors.toList());

But as an output I get an empty array.

回答1:

First, you need to change subscription to employee.

Either change your ID list to a list of Strings and populate accordingly or do something like this:

List<Employee> filteredList;
filteredList = employeeList.stream()
     .filter(employee -> ids.contains(Integer.parseInt(employee.getId())))
     .collect(Collectors.toList());

Other options include changing your Employee class to use an int as an id.

来源：https://stackoverflow.com/questions/64877285/filter-an-object-list-based-on-integerlist