NoClassDefFoundError: Could not initialize class org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping

以下是使用mbed实现上述步骤的代码：

#include "mbed.h"

// Set up SPI pins
SPI spi(A6, A5, A4);

int main() {
    // Configure SPI
    spi.format(8, 0);
    spi.frequency(1000000);
    
    // Set up serial communication
    Serial pc(USBTX, USBRX);
    pc.baud(9600);
    
    // Display introductory message
    pc.printf("SPI Loopback Code Started!\n");
    
    while (1) {
        // Send and receive data through SPI loopback
        char tx_data[] = "Hello World!";
        char rx_data[sizeof(tx_data)];
        spi.write(tx_data, sizeof(tx_data), rx_data, sizeof(rx_data));
        
        // Display received message
        pc.printf("Received Message is: %s\n", rx_data);
        
        // Wait for one second before repeating
        wait(1);
    }
}