通过流式集合对list集合中的数据进行统计

淡淡的烟草味﹌ 2024-04-17 05:36 9阅读 0赞

**主要使用的是Collectors工具类和流式集合搭配使用进行统计操作**

demo演示:

import java.util.ArrayList;
    import java.util.List;
    import java.util.Map;
    import java.util.stream.Collectors;
    public class GradeCount {
        public static void main(String[] args) {
            Student s1 = new Student("李国辉","语文",82);
            Student s2 = new Student("李国辉","数学",90);
            Student s3 = new Student("华华","语文",70);
            Student s4 = new Student("华华","数学",59);
            Student s5 = new Student("小华","化学",82);
    
            List<Student> list = new ArrayList<>();
            list.add(s1);
            list.add(s2);
            list.add(s3);
            list.add(s4);
            list.add(s5);
            System.out.println("源数据...");
            list.forEach(System.out::println);
    
            System.out.println();
            System.out.println("根据名字统计总分数..");
            Map<String, Integer> map = list.stream().collect(Collectors.groupingBy(Student::getName, Collectors.summingInt(s -> s.getGrade())));
    
            map.forEach((k,v)-> System.out.println("姓名: "+k+"-----> "+v+"分"));
        }
    }

结果:  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2xpZ2hfc3Fo_size_16_color_FFFFFF_t_70]

最近迷上了java8的新东西,有助于简化代码开发过程和编写优美的代码…

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