fastDfs的使用(图片上传)

在springcloud集群中上传图片不进行统一处理的话,会出现图片丢失的问题等,所以图片要使用分布式文件系统统一管理多个文件系统通过管理软件进行管理,得到分布式文件系统.
好处:

1. 单点故障
2. 海量存储
3. 高可用

fastDfs

FastDFS 是用 c 语言编写的一款开源的分布式文件系统。FastDFS 为互联网量身定制，充分考虑了冗余备份、负载均衡、线性扩容等机制，并注重高可用、高性能等指标，使用 FastDFS很容易搭建一套高性能的文件服务器集群提供文件上传、下载等服务。

使用docker搭建环境

在pom中引用

    cn.bestwu
    fastdfs-client-java
    1.27

添加配置文件fdfs_client.conf, 里面写上搭建fastDfs时给出的路径

tracker_server=xxx

具体的方法实现

public class FastDfsApiOpr {
     
    public static String CONF_FILENAME  = FastDfsApiOpr.class.getClassLoader()
            .getResource("fdfs_client.conf").getFile();


    /**
     * 上传文件
     * @param file
     * @param extName
     * @return
     */
    public static  String upload(byte[] file,String extName) {

        try {
            ClientGlobal.init(CONF_FILENAME);

            TrackerClient tracker = new TrackerClient();
            TrackerServer trackerServer = tracker.getConnection();
            StorageServer storageServer = null;

            StorageClient storageClient = new StorageClient(trackerServer, storageServer);
            NameValuePair nvp [] = new NameValuePair[]{
                    new NameValuePair("age", "18"),
                    new NameValuePair("sex", "male")
            };
            String fileIds[] = storageClient.upload_file(file,extName,nvp);

            System.out.println(fileIds.length);
            System.out.println("组名：" + fileIds[0]);
            System.out.println("路径: " + fileIds[1]);
            return  "/"+fileIds[0]+"/"+fileIds[1];

        } catch (Exception e) {
            e.printStackTrace();
            return  null;
        }
    }
    /**
     * 上传文件
     * @param extName
     * @return
     */
    public static  String upload(String path,String extName) {
 
        try { 
            ClientGlobal.init(CONF_FILENAME);
 
            TrackerClient tracker = new TrackerClient(); 
            TrackerServer trackerServer = tracker.getConnection(); 
            StorageServer storageServer = null;
            StorageClient storageClient = new StorageClient(trackerServer, storageServer);
            String fileIds[] = storageClient.upload_file(path, extName,null);
             
            System.out.println(fileIds.length); 
            System.out.println("组名：" + fileIds[0]); 
            System.out.println("路径: " + fileIds[1]);
            return  "/"+fileIds[0]+"/"+fileIds[1];
 
        } catch (Exception e) {
            e.printStackTrace();
            return  null;
        }
    }

    /**
     * 下载文件
     * @param groupName
     * @param fileName
     * @return
     */
    public static byte[] download(String groupName,String fileName) {
        try {
 
            ClientGlobal.init(CONF_FILENAME);
 
            TrackerClient tracker = new TrackerClient(); 
            TrackerServer trackerServer = tracker.getConnection(); 
            StorageServer storageServer = null;
 
            StorageClient storageClient = new StorageClient(trackerServer, storageServer); 
            byte[] b = storageClient.download_file(groupName, fileName);
            return  b;
        } catch (Exception e) {
            e.printStackTrace();
            return  null;
        } 
    }
     
//    @Test
//    public void testGetFileInfo(){
//        try {
//            ClientGlobal.init(conf_filename);
//
//            TrackerClient tracker = new TrackerClient();
//            TrackerServer trackerServer = tracker.getConnection();
//            StorageServer storageServer = null;
//
//            StorageClient storageClient = new StorageClient(trackerServer, storageServer);
//            FileInfo fi = storageClient.get_file_info("group1", "M00/00/00/wKgRcFV_08OAK_KCAAAA5fm_sy874.conf");
//            System.out.println(fi.getSourceIpAddr());
//            System.out.println(fi.getFileSize());
//            System.out.println(fi.getCreateTimestamp());
//            System.out.println(fi.getCrc32());
//        } catch (Exception e) {
//            e.printStackTrace();
//        }
//    }
     
//    @Test
//    public void testGetFileMate(){
//        try {
//            ClientGlobal.init(conf_filename);
//
//            TrackerClient tracker = new TrackerClient();
//            TrackerServer trackerServer = tracker.getConnection();
//            StorageServer storageServer = null;
//
//            StorageClient storageClient = new StorageClient(trackerServer,
//                    storageServer);
//            NameValuePair nvps [] = storageClient.get_metadata("group1", "M00/00/00/wKgRcFV_08OAK_KCAAAA5fm_sy874.conf");
//            for(NameValuePair nvp : nvps){
//                System.out.println(nvp.getName() + ":" + nvp.getValue());
//            }
//        } catch (Exception e) {
//            e.printStackTrace();
//        }
//    }

    /**
     * 删除文件
     * @param groupName
     * @param fileName
     */
    public static void delete(String groupName,String fileName){
        try { 
            ClientGlobal.init(CONF_FILENAME);
 
            TrackerClient tracker = new TrackerClient(); 
            TrackerServer trackerServer = tracker.getConnection(); 
            StorageServer storageServer = null;
 
            StorageClient storageClient = new StorageClient(trackerServer, 
                    storageServer); 
            int i = storageClient.delete_file(groupName,fileName);
            System.out.println( i==0 ? "删除成功" : "删除失败:"+i);
        } catch (Exception e) {
            e.printStackTrace();
            throw  new RuntimeException("删除异常,"+e.getMessage());
        } 
    }
}

菜单实现

表的设计
----一级菜单
—二级菜单
–三级菜单
设计表的时候,设计了一个父级id(fid),子级List和自己的id

private List getCourseTypesRecursion(Long fid) {
    //方案1:递归-自己调用自己,要有出口
    List sid= courseTypeMapper
            .selectList(new EntityWrapper().eq("fid", fid));
    //要有出口
    if (sid==null || sid.size()<1)
    {
        return null;
    }
    for (CourseType lid: sid) {
        //自己调用自己
        List courseTypes =lid.getCourseTypesRecursion(lid.getId());
        lid.setChildren(courseTypes);
    }
    return lid;
}