java如何实现获取客户端ip地址的示例代码

获取客户端IP地址是Java Web开发中常见的需求之一。下面是一份完整的攻略，包含了两个示例说明。

示例1：使用HttpServletRequest对象获取客户端IP地址

在Java Web开发中，可以使用HttpServletRequest对象来获取客户端IP地址。以下是一个示例代码：

import javax.servlet.http.HttpServletRequest;

public class ClientIPExample {
    public static String getClientIP(HttpServletRequest request) {
        String ipAddress = request.getHeader(\"X-Forwarded-For\");
        if (ipAddress == null || ipAddress.length() == 0 || \"unknown\".equalsIgnoreCase(ipAddress)) {
            ipAddress = request.getHeader(\"Proxy-Client-IP\");
        }
        if (ipAddress == null || ipAddress.length() == 0 || \"unknown\".equalsIgnoreCase(ipAddress)) {
            ipAddress = request.getHeader(\"WL-Proxy-Client-IP\");
        }
        if (ipAddress == null || ipAddress.length() == 0 || \"unknown\".equalsIgnoreCase(ipAddress)) {
            ipAddress = request.getHeader(\"HTTP_CLIENT_IP\");
        }
        if (ipAddress == null || ipAddress.length() == 0 || \"unknown\".equalsIgnoreCase(ipAddress)) {
            ipAddress = request.getHeader(\"HTTP_X_FORWARDED_FOR\");
        }
        if (ipAddress == null || ipAddress.length() == 0 || \"unknown\".equalsIgnoreCase(ipAddress)) {
            ipAddress = request.getRemoteAddr();
        }
        return ipAddress;
    }
}

在上述示例中，我们定义了一个静态方法getClientIP，该方法接受一个HttpServletRequest对象作为参数，并返回客户端的IP地址。该方法首先尝试从请求头中获取IP地址，如果获取不到，则从请求对象的getRemoteAddr方法中获取。

示例2：使用Spring框架获取客户端IP地址

如果你正在使用Spring框架进行开发，可以使用ServletRequestAttributes类来获取客户端IP地址。以下是一个示例代码：

import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;

public class ClientIPExample {
    public static String getClientIP() {
        ServletRequestAttributes attributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
        HttpServletRequest request = attributes.getRequest();
        String ipAddress = request.getHeader(\"X-Forwarded-For\");
        if (ipAddress == null || ipAddress.length() == 0 || \"unknown\".equalsIgnoreCase(ipAddress)) {
            ipAddress = request.getHeader(\"Proxy-Client-IP\");
        }
        if (ipAddress == null || ipAddress.length() == 0 || \"unknown\".equalsIgnoreCase(ipAddress)) {
            ipAddress = request.getHeader(\"WL-Proxy-Client-IP\");
        }
        if (ipAddress == null || ipAddress.length() == 0 || \"unknown\".equalsIgnoreCase(ipAddress)) {
            ipAddress = request.getHeader(\"HTTP_CLIENT_IP\");
        }
        if (ipAddress == null || ipAddress.length() == 0 || \"unknown\".equalsIgnoreCase(ipAddress)) {
            ipAddress = request.getHeader(\"HTTP_X_FORWARDED_FOR\");
        }
        if (ipAddress == null || ipAddress.length() == 0 || \"unknown\".equalsIgnoreCase(ipAddress)) {
            ipAddress = request.getRemoteAddr();
        }
        return ipAddress;
    }
}

在上述示例中，我们使用了Spring框架提供的RequestContextHolder类来获取当前请求的上下文信息，然后通过getRequest方法获取HttpServletRequest对象，最后获取客户端IP地址的逻辑与示例1相同。

以上就是两个示例说明，分别展示了如何使用HttpServletRequest对象和Spring框架来获取客户端IP地址的示例代码。