获取到对象中金额累加
BigDecimal amount = list.stream().map(r -> r.getAmount() == null ? BigDecimal.ZERO : r.getAmount()).reduce(BigDecimal.ZERO,BigDecimal::add);
BigDecimal amount = list.stream().map(r -> r.getAmount() == null ? BigDecimal.ZERO : r.getAmount()).reduce(BigDecimal.ZERO,BigDecimal::add);