Java8新特性之filter过滤器

2023年1月22日 738次阅读 来源: 熬夜的猫

【过滤器案例】：使用Stream对象的filter()方法过滤出集合中Person对象name属性含有”菲”字的对象

创建Person类：

public class Person {
    public static enum Sex{
        MALE,FEMALE;
    }
    private String name;
    private Sex gender;
    private int age;
    private double height;

    public Person() {
    }

    public Person(String name, Sex gender, int age, double height) {
        super();
        this.name = name;
        this.gender = gender;
        this.age = age;
        this.height = height;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public Sex getGender() {
        return gender;
    }
    public void setGender(Sex gender) {
        this.gender = gender;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
    public double getHeight() {
        return height;
    }
    public void setHeight(double height) {
        this.height = height;
    }
    @Override
    public String toString() {
        return "Person [name=" + name + ", gender=" + gender + ", age=" + age + ", height=" + height + "]";
    }

}

创建测试类，在测试类中创建一个初始化集合的静态方法：

public class Test04_collection_filter {

    //初始化集合的静态方法

   public static List<Person> createPerson(){
        List<Person> people = new ArrayList<Person>();
        Person person = new Person("张飞",Person.Sex.MALE,33,1.99);
        people.add(person);
        person = new Person("王菲",Person.Sex.FEMALE,33,1.65);
        people.add(person);
        person = new Person("刘亦菲",Person.Sex.FEMALE,33,1.68);
        people.add(person);
        person = new Person("李四",Person.Sex.MALE,33,1.76);
        people.add(person);
        person = new Person("小马",Person.Sex.MALE,33,1.71);
        people.add(person);
        person = new Person("郭靖",Person.Sex.MALE,33,1.88);
        people.add(person);
        return people;
    }
}

在该测试类中，添加main方法，用来测试filter过滤器：

public static void main(String[] args) {

        List<Person> people = createPerson();//调用初始化集合的静态方法，初始化一个集合
        Stream<Person> stream = people.stream();
        stream.filter(p -> p.getName().indexOf("菲")>-1)//过滤器中传入lambda表达式，表达式代码块中书写判断条件，返回一个布尔值
        .forEach(p -> { 
                      System.out.println(p);
        });//紧接着调用forEach方法，遍历集合，打印集合中每个对象
    }

运行main方法，控制台打印结果如下：

Person [name=王菲, gender=FEMALE, age=33, height=1.65]
Person [name=刘亦菲, gender=FEMALE, age=33, height=1.68]

本文代码资源地址：

https://github.com/gitHjx/java8.git

    原文作者：熬夜的猫
    原文地址: https://blog.csdn.net/weixin_39541657/article/details/81676622
    本文转自网络文章，转载此文章仅为分享知识，如有侵权，请联系博主进行删除。
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