jsp实现累积记账（简单表单处理和数据存储）

实现一个简单的Web服务器可以分为以下几个步骤：

1. 创建socket：使用socket()函数创建一个socket对象。

int server_socket = socket(AF_INET, SOCK_STREAM, 0);

2. 绑定socket：使用bind()函数将socket绑定到一个IP地址和端口号上。

struct sockaddr_in server_address;
server_address.sin_family = AF_INET;
server_address.sin_port = htons(80);
server_address.sin_addr.s_addr = INADDR_ANY;

bind(server_socket, (struct sockaddr*) &server_address, sizeof(server_address));

3. 监听连接请求：使用listen()函数监听连接请求。

listen(server_socket, 5);

4. 接受连接请求：使用accept()函数接受连接请求，并创建一个新的socket对象来处理连接。

struct sockaddr_in client_address;
socklen_t client_address_len = sizeof(client_address);
int client_socket = accept(server_socket, (struct sockaddr*) &client_address, &client_address_len);

5. 接收HTTP请求：使用recv()函数接收HTTP请求，可以使用循环接收直到接收完整的HTTP请求。

char request_buffer[1024];
int bytes_received = recv(client_socket, request_buffer, 1024, 0);

6. 解析HTTP请求：解析HTTP请求的方法有很多种，可以使用字符串处理函数或正则表达式来解析请求行和请求头。

7. 处理HTTP请求：根据HTTP请求的内容来处理请求，例如返回静态文件或动态生成内容。

8. 发送HTTP响应：使用send()函数发送HTTP响应，可以使用循环发送直到发送完整的HTTP响应。

char response_buffer[1024];
sprintf(response_buffer, "HTTP/1.1 200 OK\r\nContent-Length: %d\r\n\r\n%s", strlen(response_body), response_body);
send(client_socket, response_buffer, strlen(response_buffer), 0);

9. 关闭socket：使用close()函数关闭socket对象。

完整代码如下：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <netinet/in.h>

void handle_request(int client_socket) {
    char request_buffer[1024];
    int bytes_received = recv(client_socket, request_buffer, 1024, 0);
    if (bytes_received > 0) {
        request_buffer[bytes_received] = '\0';
        printf("Received request:\n%s\n", request_buffer);

        char response_body[1024];
        sprintf(response_body, "Hello, World!");

        char response_buffer[1024];
        sprintf(response_buffer, "HTTP/1.1 200 OK\r\nContent-Length: %d\r\n\r\n%s", strlen(response_body), response_body);
        send(client_socket, response_buffer, strlen(response_buffer), 0);
    }
    close(client_socket);
}

int main() {
    int server_socket = socket(AF_INET, SOCK_STREAM, 0);
    if (server_socket == -1) {
        perror("Error creating socket");
        exit(1);
    }

    struct sockaddr_in server_address;
    server_address.sin_family = AF_INET;
    server_address.sin_port = htons(80);
    server_address.sin_addr.s_addr = INADDR_ANY;

    if (bind(server_socket, (struct sockaddr*) &server_address, sizeof(server_address)) == -1) {
        perror("Error binding socket");
        exit(1);
    }

    if (listen(server_socket, 5) == -1) {
        perror("Error listening for connections");
        exit(1);
    }

    while (1) {
        struct sockaddr_in client_address;
        socklen_t client_address_len = sizeof(client_address);
        int client_socket = accept(server_socket, (struct sockaddr*) &client_address, &client_address_len);
        if (client_socket == -1) {
            perror("Error accepting connection");
            exit(1);
        }

        handle_request(client_socket);
    }

    close(server_socket);

    return 0;
}