编辑“︁Java 8新特性”︁（章节）

== 实际应用案例 ==
以下是一个结合 Lambda 表达式和 Stream API 的实际案例，用于统计员工列表中薪资高于平均值的员工：

<syntaxhighlight lang="java">
class Employee {
    String name;
    double salary;

    Employee(String name, double salary) {
        this.name = name;
        this.salary = salary;
    }

    public double getSalary() { return salary; }
    public String getName() { return name; }
}

public class Main {
    public static void main(String[] args) {
        List<Employee> employees = Arrays.asList(
            new Employee("Alice", 5000),
            new Employee("Bob", 6000),
            new Employee("Charlie", 7000)
        );

        double averageSalary = employees.stream()
                                       .mapToDouble(Employee::getSalary)
                                       .average()
                                       .orElse(0);

        System.out.println("Average Salary: " + averageSalary);

        employees.stream()
                .filter(e -> e.getSalary() > averageSalary)
                .forEach(e -> System.out.println(e.getName()));
    }
}
</syntaxhighlight>

=== 输出 ===
<pre>
Average Salary: 6000.0
Charlie
</pre>

=== 解释 ===
- `mapToDouble()` 将员工对象映射为薪资值。
- `average()` 计算平均薪资。
- `filter()` 过滤出薪资高于平均值的员工。