Java中用于过滤的Lambda表达式

Question

null

public class Person
{
    private String name;
    private List<Hobby> hobbyList = new ArrayList<>();
    ...
}

java：

public class Hobby
{
    private String name;
    private Person person;
    private Type type;
    ...
}

type.java：

public class Type
{
    private String name;
    private List<Hobby> hobbyList = new ArrayList<>();
    ...
}

人与嗜好之间是1:m关系，类型与嗜好之间是1:m关系。

List<Person> filteredList = new LinkedList<>();
for (Person p : persons)
{
    for (Hobby h : p.getHobbyList())
    {
        if(h.getType.getName.equals("Ball"))
        {
            if(!filteredList.contains(p))
            {
                filteredList.add(p);
            }
        }
    }
}

Answer 1

做为

List<Person> filteredList = persons.stream()
                .filter(p -> p.getHobbyList().stream().anyMatch(h -> h.getType().getName().equals("Ball")))
                .collect(Collectors.toList());

[更新]

我看到你更新了问题。根据您的更新，以下操作应该适用于您：

Set<Person> filteredSet = persons.stream()
                .filter(p -> p.getHobbyList().stream().anyMatch(h -> h.getType().getName().equals("Ball")))
                .collect(Collectors.toSet());