java8stream累加_使⽤java8的stream对数组进⾏求和1.对BigDecimal类型的值求和
List> list = new ArrayList<>();
Map stu1 = new HashMap();
stu1.put("name", "卫庄");
stu1.put("score", new BigDecimal(80));
list.add(stu1);
Map stu2 = new HashMap();
stu2.put("name", "盖聂");
stu2.put("score", new BigDecimal(90));
list.add(stu2);
Map stu3 = new HashMap();
stu3.put("name", "天明");
stu3.put("score", new BigDecimal(60));
list.add(stu3);
BigDecimal sum = list.stream().map(x -> new
("score").toString())).reduce(BigDecimal.ZERO,BigDecimal::add);
System.out.println("三⼈总分："+sum);
//结果：三⼈总分：230
2.对double型的值求和
List> list = new ArrayList<>();
Map stu1 = new HashMap();
stu1.put("name", "卫庄");
stu1.put("score", 80.0);
list.add(stu1);
Map stu2 = new HashMap();
stu2.put("name", "盖聂");
stu2.put("score", 90.0);
list.add(stu2);
java streamMap stu3 = new HashMap();
stu3.put("name", "天明");
stu3.put("score", 60.0);
list.add(stu3);
double sum = list.stream().collect(Collectors.summingDouble(x -> ((Double) x.get("score"))));
System.out.println("三⼈总分："+sum); //结果：三⼈总分：230

版权声明：本站内容均来自互联网，仅供演示用，请勿用于商业和其他非法用途。如果侵犯了您的权益请与我们联系QQ:729038198，我们将在24小时内删除。