FastDFS实现原理及流程

一、什么是FastDFS

是一个开源的轻量级分布式文件系统，对文件进行管理。

功能：
文件存储，文件访问，文件上传下载。

单次存储大小：
4k–500M

好处：
解决了大量存储和负载均衡问题。

用处：
适合文件类的在线服务，比如视频网站腾讯视频，相册看图网站图虫。

二、服务端两个角色：

跟踪器（tracker）:
做调度工作，起到负载均衡的作用。管理集群，也可以实现集群。每个tracker阶段地位平等，负责收集storage的状态。

存储节点（storage）:
实际保存文件storage分为多个组，每个组保存的文件时不同的。
每个组有多个组成员，组成员保存的内容是一样的，组成员地位平等，没有主从概念。

三、执行流程

1.初始化连接配置
2.创建一个Tracker客户端，目的是为了连接Tracker,获取TrackerServer对象
3.通过TrackerServer创建一个Storage客户端对象，该对象用来操作Storage
4.通过Storage实现上传下载
5.获取文件上传下载信息

测试代码：

1、pom配置（引入fastdfs配置即可）：

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"><parent><artifactId>Fast111</artifactId><groupId>cn.cfg</groupId><version>1.0-SNAPSHOT</version><relativePath>fastDFSDemo/Fast111/pom.xml</relativePath></parent><modelVersion>4.0.0</modelVersion><artifactId>Fast2</artifactId><dependencies><dependency><groupId>junit</groupId><artifactId>junit</artifactId><version>4.11</version><scope>test</scope></dependency><dependency><groupId>org.csource.fastdfs</groupId><artifactId>fastdfs</artifactId><version>1.2</version></dependency></dependencies></project>

2、Resources包下的配置（client.conf）：
引入虚拟机端口号,可直接复制，更改端口号即可

# connect timeout in seconds
# default value is 30s
connect_timeout=30# network timeout in seconds
# default value is 30s
network_timeout=60# the base path to store log files
base_path=/home/fastdfs# tracker_server can ocur more than once, and tracker_server format is
# "host:port", host can be hostname or ip address
<!--引入虚拟机地址-->
tracker_server=192.168.200.128:22122#standard log level as syslog, case insensitive, value list:
### emerg for emergency
### alert
### crit for critical
### error
### warn for warning
### notice
### info
### debug
log_level=info# if use connection pool
# default value is false
# since V4.05
use_connection_pool = false# connections whose the idle time exceeds this time will be closed
# unit: second
# default value is 3600
# since V4.05
connection_pool_max_idle_time = 3600# if load FastDFS parameters from tracker server
# since V4.05
# default value is false
load_fdfs_parameters_from_tracker=false# if use storage ID instead of IP address
# same as tracker.conf
# valid only when load_fdfs_parameters_from_tracker is false
# default value is false
# since V4.05
use_storage_id = false# specify storage ids filename, can use relative or absolute path
# same as tracker.conf
# valid only when load_fdfs_parameters_from_tracker is false
# since V4.05
storage_ids_filename = storage_ids.conf#HTTP settings
http.tracker_server_port=80#use "#include" directive to include HTTP other settiongs
##include http.conf

3、测试代码块（FastDFSTest.java）：

import org.csource.fastdfs.ClientGlobal;
import org.csource.fastdfs.StorageClient;
import org.csource.fastdfs.TrackerClient;
import org.csource.fastdfs.TrackerServer;public class TestFastDFS{public static String[] upload(String conFilename, String fileName) throws Exception{// 1.初始化连接配置ClientGlobal.init(conFilename);// 2.创建跟踪器客户端 tracker客户端TrackerClient trackerClient = new TrackerClient();//3. 通过tracker客户端连接  获得trackerServerTrackerServer trackerServer = trackerClient.getConnection();//4. 通过跟踪器客户端获取存储节点对象StorageClient storageClient = new StorageClient(trackerServer, null);//5.执行上传String[] strings = storageClient.upload_appender_file(fileName, null, null);//获取返回值return strings;}public static void main(String[] args) throws Exception {String tracker ="E:\\9.19fastDFSDemo\\Fast111\\Fast2\\src\\main\\resources\\fdfs_client.conf";//设置上传图片的本地路径String filerName="D:\\test\\ad53a60.jpg";String[] uploads = upload(tracker, filerName);for (String upload : uploads) {//打印返回值System.out.println(upload);}}
}

控制台打印结果：

浏览器测试（输入端口号+组名+文件名）：