strm().filter().collect()和stream().map().collect()的作用

全栈程序员-用户IM • 2022年10月31日上午7:00 • 未分类

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Jetbrains全家桶1年46，售后保障稳定

在看代码的时候看到了相关方法，自己在写了个例子练习一下

public class People { 
   
    private Integer id;
    private String name;
    private Boolean sex;
//省略
}

Jetbrains全家桶1年46，售后保障稳定

public class Filter { 
   
    public static void main(String[] args) { 
   
        People people1 = new People(1, "Ligs", true);
        People people2 = new People(2, "Songzx", false);
        People people3 = new People(3, "Jinzg", true);
        People people4 = new People(4, "Liuzx", false);
        People people5 = new People(5, "Hedx", true);
        People people6 = new People(6, "Quansm", false);
        People people7 = new People(7, "Liangsz", true);
        People people8 = new People(8, "Chisz", true);
        ArrayList<People> list = new ArrayList<People>() { 
   { 
   
            add(people1);
            add(people2);
            add(people3);
            add(people4);
            add(people5);
            add(people6);
            add(people7);
            add(people8);
        }};
        System.out.println(list.stream().filter(People::getSex).collect(Collectors.toList()));
        //[People{id=1, name='Ligs', sex=true}, People{id=3, name='Jinzg', sex=true}, People{id=5, name='Hedx', sex=true}, People{id=7, name='Liangsz', sex=true}, People{id=8, name='Chisz', sex=true}]
        //过滤掉sex为false值的对象
        System.out.println(list.stream().map(People::getSex).collect(Collectors.toList()));
        //[true, false, true, false, true, false, true, true]
        //获取list中sex属性的集合
    }
}