2.java8流的使用 stream的筛选与切片filter，limit，skip，distinct

本文主要是介绍2.java8流的使用 stream的筛选与切片filter，limit，skip，distinct，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

1.代码

准备的bean类

/*** 创建日期：2021/10/29 14:01** @author tony.sun* 类说明：*/public class Employee {private String name;private int age;private double salary;public Employee(String name, int age, double salary) {this.name = name;this.age = age;this.salary = salary;}public String getName() {return name;}public void setName(String name) {this.name = name;}public int getAge() {return age;}public void setAge(int age) {this.age = age;}public double getSalary() {return salary;}public void setSalary(double salary) {this.salary = salary;}@Overridepublic String toString() {return "Employee{" +"name='" + name + '\'' +", age=" + age +", salary=" + salary +'}';}
//    去重@Overridepublic boolean equals(Object o) {if (this == o) return true;if (o == null || getClass() != o.getClass()) return false;Employee employee = (Employee) o;return age == employee.age &&Double.compare(employee.salary, salary) == 0 &&name.equals(employee.name);}@Overridepublic int hashCode() {return Objects.hash(name, age, salary);}
}

其中equals与hashCode是为了去重
添加值

List<Employee> employees=Arrays.asList(new Employee("张三",18,9999.99),new Employee("李四",58,5555.55),new Employee("王五",26,3333.33),new Employee("赵六",36,6666.66),new Employee("田七",12,8888.88),new Employee("田七",12,8888.88));

stream要终止操作才执行，不然就不执行
过滤：这里是过滤，返回大于35的age值

//中间操作，不会执行Stream<Employee> stream = employees.stream().filter((e) -> {System.out.println("Stream API 的中间操作");return e.getAge()>35;//返回age大于35的});//终止操作：一次性全部内容，即惰性求值stream.forEach(System.out::println);

limit(2）表示限制，限制流的数量为2，取前面两个，这个会执行两次

@Testpublic void test2(){employees.stream().filter((e)->{System.out.println("短路！");return e.getSalary()>5000;}).limit(2)//执行两次.forEach(System.out::println);}

skip:表示跳过，前面的值，取后面的，这个会执行全部

//跳skip@Testpublic void test3(){employees.stream().filter((e)->{System.out.println("短路！");return e.getSalary()>5000;}).skip(2)//执行了5次.forEach(System.out::println);}

distinct不同的，不能够一样

 @Testpublic void test4(){employees.stream().filter((e)->{System.out.println("去重");return e.getSalary()>5000;}).distinct().forEach(System.out::println);}