68、Java 中的 Lambda 与流操作详解

Java 中的 Lambda 与流操作详解

1. 员工薪资的求和与求平均值

在 Java 中，我们可以使用流操作来对员工薪资进行求和与求平均值。以下是相关代码示例：

// sum of Employee salaries with DoubleStream sum method
System.out.printf(
    "%nSum of Employees' salaries (via sum method): %.2f%n",
    list.stream()
        .mapToDouble(Employee::getSalary)
        .sum());

// calculate sum of Employee salaries with Stream reduce method
System.out.printf(
    "Sum of Employees' salaries (via reduce method): %.2f%n",
    list.stream()
        .mapToDouble(Employee::getSalary)
        .reduce(0, (value1, value2) -> value1 + value2));

// average of Employee salaries with DoubleStream average method
System.out.printf("Average of Employees' salaries: %.2f%n",
    list.stream()
        .mapToDouble(Empl