java 获取ip

//获取ip
String ip = request.getHeader("x-forwarded-for"); 
    if(ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) { 
        ip = request.getHeader("Proxy-Client-IP"); 
    } 
    if(ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) { 
        ip = request.getHeader("WL-Proxy-Client-IP"); 
    } 
    if(ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) { 
        ip = request.getRemoteAddr(); 
    }