import java.util.ArrayList; import java.util.List; public class Code { public static void main(String[] args) { List<User> users = new ArrayList<>(); users.add(new User("張三", "1@qq.com")); users.add(new User("李四", "2@qq.com")); // 查找名稱為”張三“的用戶 User user = users.stream() .filter(u -> u.getName().equals("張三")) .findAny() .orElse(null); System.out.println("==============="); } private static class User { private String name; private String email; public User(String name, String email) { this.name = name; this.email = email; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String getEmail() { return email; } public void setEmail(String email) { this.email = email; } } }