计算正整数n1到n2的累加和（n1、n2的值由键盘输入）

以下是计算正整数n1到n2的累加和的Java代码示例：

import java.util.Scanner;

public class CalculateSum {
    public static void main(String[] args) {
        int n1, n2, sum = 0;
        Scanner scanner = new Scanner(System.in);

        System.out.print("输入第一个正整数n1: ");
        n1 = scanner.nextInt();

        System.out.print("输入第二个正整数n2: ");
        n2 = scanner.nextInt();

        for (int i = n1; i <= n2; i++) {
            sum += i;
        }

        System.out.println("n1到n2的累加和为: " + sum);
    }
}