nginx作为服务器分发请求与静态代理，负载均衡的神器，一些必备的使用技巧，是需要我们关注的

1.java后端获取ip的代码片段

//1.通过nginx中获取ip地址
protected String getIp() {
    String ip = request.getHeader("X-Real-IP");
    if(StringUtils.isEmpty(ip) || "unknown".equalsIgnoreCase(ip)) { 
        ip = request.getHeader("x-forwarded-for"); 
    }
    if(StringUtils.isEmpty(ip) || "unknown".equalsIgnoreCase(ip)) { 
        ip = request.getHeader("Proxy-Client-IP"); 
    }
    if(StringUtils.isEmpty(ip) || "unknown".equalsIgnoreCase(ip)) { 
        ip = request.getHeader("WL-Proxy-Client-IP"); 
    } 
    if(StringUtils.isEmpty(ip) || "unknown".equalsIgnoreCase(ip)) { 
        ip = request.getRemoteAddr(); 
    }
    return ip; 
}

2.ngxin配置ip策略

1. server代码段，一层nginx代理添加以下内容：
   proxy_set_header X-Real-IP $remote_addr;
   proxy_set_header X-Real-Port $remote_port;
   proxy_set_header X-Forwarded-For $remote_addr;

2. server代码段，多层反向代理下，最外层ngxin添加一下内容：
   proxy_set_header X-Real-IP $remote_addr;
   proxy_set_header X-Real-Port $remote_port;
   proxy_set_header X-Forwarded-For $remote_addr;

3. 非最外层nginx，可以添加一下内容：
   proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;

4. 示范代码,展示本地使用nginx的代理分发

   server {
        listen  8880;
        server_name  leanboot.com;
        #charset koi8-r;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Real-Port $remote_port;
        proxy_set_header X-Forwarded-For $remote_addr;
        location / {
            proxy_pass http://127.0.0.1:8080/;
        }
        location /files-server/ {
            proxy_pass http://127.0.0.1:8088/;
        }
   }