在 Spring Boot 中使用 Filters 实现请求过滤和预处理

import org.springframework.stereotype.Component;
 
import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
 
@Component
public class SimpleCORSFilter implements Filter {
 
    @Override
    public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException {
        HttpServletResponse response = (HttpServletResponse) res;
        HttpServletRequest request = (HttpServletRequest) req;
 
        response.setHeader("Access-Control-Allow-Origin", "*");
        response.setHeader("Access-Control-Allow-Methods", "POST, GET, OPTIONS, DELETE");
        response.setHeader("Access-Control-Max-Age", "3600");
        response.setHeader("Access-Control-Allow-Headers", "x-requested-with, Content-Type");
 
        if ("OPTIONS".equalsIgnoreCase(request.getMethod())) {
            response.setStatus(HttpServletResponse.SC_OK);
        } else {
            chain.doFilter(req, res);
        }
    }
 
    @Override
    public void init(FilterConfig filterConfig) {
        // 初始化代码，如果有必要的话
    }
 
    @Override
    public void destroy() {
        // 销毁代码，如果有必要的话
    }
}

这段代码定义了一个简单的跨域资源共享（CORS）Filter，用于处理HTTP请求并设置适当的CORS头部。在实际的应用中，你可能需要根据具体需求调整这些头部的值。这个Filter被标记为@Component，Spring Boot会自动将其加入到Filter链中。