//X-Forwarded-For：Squid 服务代理
    String ipAddresses = request.getHeader("X-Forwarded-For");

    if (ipAddresses == null || ipAddresses.length() == 0 || "unknown".equalsIgnoreCase(ipAddresses)) {
        //Proxy-Client-IP：apache 服务代理
        ipAddresses = request.getHeader("Proxy-Client-IP");
    }

    if (ipAddresses == null || ipAddresses.length() == 0 || "unknown".equalsIgnoreCase(ipAddresses)) {
        //WL-Proxy-Client-IP：weblogic 服务代理
        ipAddresses = request.getHeader("WL-Proxy-Client-IP");
    }

    if (ipAddresses == null || ipAddresses.length() == 0 || "unknown".equalsIgnoreCase(ipAddresses)) {
        //HTTP_CLIENT_IP：有些代理服务器
        ipAddresses = request.getHeader("HTTP_CLIENT_IP");
    }

    if (ipAddresses == null || ipAddresses.length() == 0 || "unknown".equalsIgnoreCase(ipAddresses)) {
        //X-Real-IP：nginx服务代理
        ipAddresses = request.getHeader("X-Real-IP");
    }

    //有些网络通过多层代理，那么获取到的ip就会有多个，一般都是通过逗号（,）分割开来，并且第一个ip为客户端的真实IP
    if (ipAddresses != null && ipAddresses.length() != 0) {
        ip = ipAddresses.split(",")[0];
    }

    //还是不能获取到，最后再通过request.getRemoteAddr();获取
    if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ipAddresses)) {
        ip = request.getRemoteAddr();
    }

    // ip配置
    if (ip.equals("127.0.0.1") || ip.endsWith("0:0:0:0:0:0:1")) {
        // 根据网卡取本机配置的IP
        return "127.0.0.1";
    }

我们有的时候会在service层获取request填充一些诸如用户名和IP地址等信息，这个时候如果不想从Controller层传request，可以在service直接使用

/**
  *在service层获取request
**/
public static HttpServletRequest getHttpServletRequest() {
        HttpServletRequest request = ((ServletRequestAttributes) RequestContextHolder.getRequestAttributes()).getRequest();
        return request;
    }

    /**
     * 返回服务器路径
     * @return
     */
    public static String getServerPath() {
        HttpServletRequest request = getHttpServletRequest();
        StringBuilder stringBuilder = new StringBuilder();
        stringBuilder.append(request.getScheme());  //http
        stringBuilder.append("://");
        stringBuilder.append(request.getServerName());  //127.0.0.1
        stringBuilder.append(":");
        stringBuilder.append(request.getServerPort());  //8080
        stringBuilder.append(request.getContextPath()); //项目名称
        return stringBuilder.toString();  //http：//127.0.0.1:8080/
    }

 

直接调用打印即可
/** 
 * 获取本机IP 
 */  
public static String getLocalIP() {  
    String ip = "";  
    try {  
        if(isLinux()){  
            Enumeration<?> e1 = (Enumeration<?>) NetworkInterface  
                    .getNetworkInterfaces();  
            while (e1.hasMoreElements()) {  
                NetworkInterface ni = (NetworkInterface) e1.nextElement();  
                if (!ni.getName().equals("eth0")) {  
                    continue;  
                } else {  
                    Enumeration<?> e2 = ni.getInetAddresses();  
                    while (e2.hasMoreElements()) {  
                        InetAddress ia = (InetAddress) e2.nextElement();  
                        if (ia instanceof Inet6Address)  
                            continue;  
                        ip = ia.getHostAddress();  
                    }  
                    break;  
                }  
            }  
        }else{  
            ip = InetAddress.getLocalHost().getHostAddress().toString();  
        }  
              
    } catch (Exception e) {  
        e.printStackTrace();  
    }  
  
    return ip;  
}  


 public static void main(String[] args) {
      System.out.println( "本机IP："+getLocalIP());
    }

输出结果下图

获取服务器的IP和端口
struts2 获取request
HttpServletRequest requet=ServletActionContext.getRequest();
requet.getScheme()+"?/"+requet.getServerName()+":"+requet.getServerPort()
(例如)结果为：http://localhost:8080/




方法
释义




request.getHeader(“User-Agent”);
//就是取得客户端的系统版本


request.getRemoteAddr();
//取得客户端的IP


request.getRemoteHost();
//取得客户端的主机名


request.getRemotePort();
//取得客户端的端口


request.getRemoteUser();
//取得客户端的用户


request.getLocalAddr();
//取得服务器IP


request.getLocalPort();
//取得服务器端口


1、JSP中获得当前应用的相对路径和绝对路径
根目录所对应的绝对路径:request.getRequestURI()

文件的绝对路径 　:application.getRealPath(request.getRequestURI());

当前web应用的绝对路径 :application.getRealPath("/");

取得请求文件的上层目录:new File(application.getRealPath(request.getRequestURI())).getParent()
2 Servlet中获得当前应用的相对路径和绝对路径
根目录所对应的绝对路径:request.getServletPath();

文件的绝对路径 :request.getSession().getServletContext().getRealPath(request.getRequestURI())

当前web应用的绝对路径 :servletConfig.getServletContext().getRealPath("/");

(ServletContext对象获得几种方式：

javax.servlet.http.HttpSession.getServletContext()

javax.servlet.jsp.PageContext.getServletContext()

javax.servlet.ServletConfig.getServletContext()

)
3.Java类中获得绝对路径
根据java.io.File的Doc文挡，可知: 默认情况下new File("/")代表的目录为：System.getProperty(“user.dir”)。
拓展
上面的获取IP方法，只能获取到127.0.0.1

在window下使用 InetAddress.getLocalHost().getHostAddress()
这种方法在linux却只能取到127.0.0.1这个让人无奈的地址。。。这简直是让人不能忍受的啊。。。这种地址不用获取，我们谁不知道。。。 
在网上搜索了很多，发现说这个问题的并不多，所以，我把找到的一段代码分享给大家。。。当然这段代码需要jdk1.5以上版本 

//---代码
Enumeration<NetworkInterface> netInterfaces = null;   
try {   
    netInterfaces = NetworkInterface.getNetworkInterfaces();   
    while (netInterfaces.hasMoreElements()) {   
        NetworkInterface ni = netInterfaces.nextElement();   
        System.out.println("DisplayName:" + ni.getDisplayName());   
        System.out.println("Name:" + ni.getName());   
        Enumeration<InetAddress> ips = ni.getInetAddresses();   
        while (ips.hasMoreElements()) {   
            System.out.println("IP:"  
            + ips.nextElement().getHostAddress());   
        }   
    }   
} catch (Exception e) {   
    e.printStackTrace();   
}  

Enumeration<NetworkInterface> netInterfaces = null;
try {
        netInterfaces = NetworkInterface.getNetworkInterfaces();
        while (netInterfaces.hasMoreElements()) {
                NetworkInterface ni = netInterfaces.nextElement();
                System.out.println("DisplayName:" + ni.getDisplayName());
                System.out.println("Name:" + ni.getName());
                Enumeration<InetAddress> ips = ni.getInetAddresses();
                while (ips.hasMoreElements()) {
                        System.out.println("IP:"
                        + ips.nextElement().getHostAddress());
                }
        }
} catch (Exception e) {
        e.printStackTrace();
}

// 这段代码会输出计算机中所有设备的ip


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