如何在Spring框架中配置RequestInterceptor来设置HTTP请求的Host头？

在Spring框架中，你可以通过自定义`RequestInterceptor`并将其添加到全局的`WebMvcConfigurer`接口的实现类中来设置HTTP请求的Host头。以下是一个简单的步骤：

1. 首先，创建一个实现了`HandlerInterceptorAdapter`接口的类，例如`CustomHostHeaderInterceptor`。这个接口有几个方法，其中`preHandle()`方法会在处理每个HTTP请求之前被调用。

import org.springframework.web.servlet.HandlerInterceptor;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class CustomHostHeaderInterceptor implements HandlerInterceptor {

    private String customHost;

    public CustomHostHeaderInterceptor(String customHost) {
        this.customHost = customHost;
    }

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        if (customHost != null) {
            request.setRequestURI(customHost + request.getRequestURI());
            request.setServerName(customHost);
            request.setRemoteAddr(request.getRemoteAddr());
        }
        return true;
    }

    // 其他方法如postHandle()和afterCompletion()可以根据需要实现
}

2. 然后，在你的`WebMvcConfigurer`实现类中注册这个拦截器：

import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

@Configuration
public class WebConfig implements WebMvcConfigurer {

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(new CustomHostHeaderInterceptor("your-custom-host.com"))
                .addPathPatterns("/**"); // 设置拦截所有路径
    }
}

这里的`"your-custom-host.com"`应替换为你想要设置的主机名。