fastdfs下载报空指针

项目部署了一台tracker节点，两台storage节点，下载jar包时，总是时不时的下载不下来，报空指针，代码如下

//moduleVersion.getFileUrl()的结果group1/M00/00/00/CgpNpl0Z6tCAQkvZA53GMmLvqiA741.jar
String groupName = moduleVersion.getFileUrl().substring(0, .indexOf("/"));String routeFileName =moduleVersion.getFileUrl().substring(moduleVersion.getFileUrl().indexOf("/") + 1);byte[] fileByte = FastDFSClientUtil.downFile(groupName, routeFileName);

FastDFSClientUtil工具类的代码如下：

package com.supconit.data.algorithm.platform.util;import com.supconit.data.algorithm.platform.common.entity.FastDfs.FastDFSFile;
import org.apache.commons.io.IOUtils;
import org.apache.commons.lang.StringUtils;
import org.csource.common.NameValuePair;
import org.csource.fastdfs.*;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.io.ClassPathResource;import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;/*** Created by dell on 2019/4/25.*/
public class FastDFSClientUtil {@Autowiredprivate static String STORAGE_SERVER_GROUP = "group1";@Autowiredprivate static String STORAGE_SERVER_PORT = "23000";private static TrackerClient trackerClient;private static TrackerServer trackerServer;private static StorageClient storageClient;private static StorageServer storageServer;private static org.slf4j.Logger logger = LoggerFactory.getLogger(FastDFSClientUtil.class);static {try {ClassPathResource classPathResource = new ClassPathResource("fdfs_client.conf");//创建临时文件，将fdfs_client.conf的值赋值到临时文件中，创建这个临时文件的原因是springboot打成jar后无法获取classpath下文件String tempPath =System.getProperty("java.io.tmpdir") + System.currentTimeMillis()+".conf";File f = new File(tempPath);IOUtils.copy(classPathResource.getInputStream(),new FileOutputStream(f));ClientGlobal.init(f.getAbsolutePath());trackerClient = new TrackerClient();trackerServer = trackerClient.getConnection();//给dfs发送一个消息，不然会报recv package size -1!=10错误ProtoCommon.activeTest(trackerServer.getSocket());} catch (Exception e) {logger.error("FastDFS Client Init Fail!",e);}}
/*** 上传文件* storepath 0代表input，1代表算法，2代表output*/public static String[] upload(FastDFSFile file,String storepath) {logger.info("File Name: " + file.getName() + "File Length:" + file.getContent().length);NameValuePair[] meta_list = new NameValuePair[1];meta_list[0] = new NameValuePair("author", file.getAuthor());long startTime = System.currentTimeMillis();String[] uploadResults = null;try {String storageIp = getStorageServerIp(trackerClient,trackerServer);if (StringUtils.isBlank(storageIp)){logger.error("stroageIp is null, error code:" + storageClient.getErrorCode());}storageServer =getStorageServer(storageIp,storepath);storageClient = new StorageClient(trackerServer, storageServer);uploadResults = storageClient.upload_file(file.getContent(), file.getExt(), meta_list);} catch (IOException e) {logger.error("IO Exception when uploadind the file:" + file.getName(), e);} catch (Exception e) {logger.error("Non IO Exception when uploadind the file:" + file.getName(), e);}logger.info("upload_file time used:" + (System.currentTimeMillis() - startTime) + " ms");if (uploadResults == null) {logger.error("upload file fail, error code:" + storageClient.getErrorCode());}String groupName = uploadResults[0];String remoteFileName = uploadResults[1];logger.info("upload file successfully!!!" + "group_name:" + groupName + ", remoteFileName:" + " " + remoteFileName);return uploadResults;}/*** 下载* @param groupName* @param remoteFileName* @return*/public static byte[] downFile(String groupName, String remoteFileName) {try {storageServer = trackerClient.getStoreStorage(trackerServer);storageClient = new StorageClient(trackerServer, storageServer);byte[] fileByte = storageClient.download_file(groupName, remoteFileName);return fileByte;} catch (IOException e) {logger.error("IO Exception: Get File from Fast DFS failed", e);} catch (Exception e) {logger.error("Non IO Exception: Get File from Fast DFS failed", e);}return null;}/*** 删除文件* @param groupName* @param remoteFileName* @throws Exception*/public static void deleteFile(String groupName, String remoteFileName)throws Exception {storageClient = new StorageClient(trackerServer, storageServer);int i = storageClient.delete_file(groupName, remoteFileName);logger.info("delete file successfully!!!" + i);}/*** 获得可用的storage IP** @param trackerClient* @param trackerServer* @return 返回storage IP*/private static String getStorageServerIp(TrackerClient trackerClient, TrackerServer trackerServer) {String storageIp = null;if (trackerClient != null && trackerServer != null) {try {StorageServer storageServer = trackerClient.getStoreStorage(trackerServer, STORAGE_SERVER_GROUP);storageIp = storageServer.getSocket().getInetAddress().getHostAddress();} catch (IOException e) {e.printStackTrace();}}return storageIp;}/*** 得到Storage服务** @param storageIp* @param storepath 0代表input服务的jar包，1代表算法服务的jar包，2代表output服务的jar包* @return 返回Storage服务*/private static StorageServer getStorageServer(String storageIp,String storepath) {StorageServer storageServer = null;if (storageIp != null && !("").equals(storageIp) &&null != storepath && !("").equals(storepath)) {try {storageServer = new StorageServer(storageIp, Integer.parseInt(STORAGE_SERVER_PORT), Integer.parseInt(storepath));} catch (IOException e) {e.printStackTrace();}}return storageServer;}
}

报错如下：

我怀疑是下载的时候，两台storage存储节点之间没有同步完成，例如tracker分配storageA存的jar包，下载的时候从storageB去下载，这个时候storageA还没有把jar包同步到storageB，所以会报空指针，然后修改的tracker的conf文件，将download_server=0 修改为1，修改完后重启tracker服务器

download_server=1
#选择哪个storeServer最为下载服务器，0.轮询，1.哪个为源则哪个下载

再次测试，发现问题还是没有解决，然后开始了无限的打印之路，慢慢调试。。。
然后将代码修改成如果的第一次从fastdfs上下载失败的话，就再下载一次，没有报错了，实在是不知道原因。。。。

  String groupName =moduleVersion.getFileUrl().substring(0, moduleVersion.getFileUrl().indexOf("/"));String routeFileName =moduleVersion.getFileUrl().substring(moduleVersion.getFileUrl().indexOf("/") + 1);byte[] fileByte = FastDFSClientUtil.downFile(groupName, routeFileName);//有的时候会从fastdfs下载失败，如果下载失败的话，那么就在从fastdfs上下载一次if (null == fileByte){fileByte = FastDFSClientUtil.downFile(groupName, routeFileName);}

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