如何在Scalatra Servlet中获取请求参数？

Question

我目前有一个可用的Scalactra servlet。

# include <bcm2835.h>
# include <stdio.h>
# include <time.h>
# include <stdlib.h>

# define ECHO RPI_V2_GPIO_P1_03
# define TRIG RPI_V2_GPIO_P1_05

int main(int argc, char **argv) {
if (!bcm2835_init())
    return 1;

bcm2835_gpio_fsel(ECHO, BCM2835_GPIO_FSEL_INPT);
bcm2835_gpio_fsel(TRIG, BCM2835_GPIO_FSEL_OUTP);

time_t clockstart = 0;
time_t clockstop = 0;

bcm2835_gpio_write(ECHO, LOW);
delay(2);

printf("trigger\n");

bcm2835_gpio_write(TRIG, HIGH);
usleep(10);
bcm2835_gpio_write(TRIG, LOW);

printf("measure\n");


while (bcm2835_gpio_lev(ECHO) == 0) {
    clockstart = time(NULL);
}

printf("B: %i\n", (int)clockstart);

while (bcm2835_gpio_lev(ECHO) == 1) {
    clockstop = time(NULL);
}

printf("E: %i\n", (int)clockstop);

time_t delta = clockstop - clockstart;

printf("D: %i\n", delta);

double distance = (delta * 340) / 2;

printf("DISTANCE: %i\n", distance);

bcm2835_close();
return 0;
}

文件路径目前是硬编码的。有什么办法可以让用户输入文件路径参数吗？帮助非常有用！