JAVA API 链接HA方式下的HDFS

private static String ClusterName = "nsstargate"; private static final String HADOOP_URL = "hdfs://"+ClusterName; public static Configuration conf; static { conf = new Configuration(); conf.set("fs.defaultFS", HADOOP_URL); conf.set("dfs.nameservices", ClusterName); conf.set("dfs.ha.namenodes."+ClusterName, "nn1,nn2"); conf.set("dfs.namenode.rpc-address."+ClusterName+".nn1", "172.16.50.24:8020"); conf.set("dfs.namenode.rpc-address."+ClusterName+".nn2", "172.16.50.21:8020"); //conf.setBoolean(name, value);
        conf.set("dfs.client.failover.proxy.provider."+ClusterName, "org.apache.hadoop.hdfs.server.namenode.ha.ConfiguredFailoverProxyProvider"); }

经过java api链接Hadoop集群时，若是集群支持HA方式，那么能够经过以下方式设置来自动切换到活动的master节点上。其中，ClusterName 是能够任意指定的，跟集群配置无关，dfs.ha.namenodes.ClusterName也能够任意指定名称，有几个master就写几个，后面根据相应的设置添加master节点地址便可。java

上传文件到HDFS的代码以下，至于读取等其余操做，能够参考网络上其余文章。node

/** * 上传文件到HDFS上去 */
    private static void uploadToHdfs() throws IOException { String localSrc = "E:\\test\\article01.txt"; String dst = "/user/test/article04.txt"; FileSystem fs = FileSystem.get(URI.create(HADOOP_URL), conf); long start = new Date().getTime(); /* InputStream in = new FileInputStream(localSrc); InputStreamReader isr = new InputStreamReader(in, "GBK"); OutputStream out = fs.create(new Path(HADOOP_URL+dst), true); IOUtils.copy(isr, out, "UTF8");*/
        
        //该方法更快
        FSDataOutputStream outputStream=fs.create(new Path(dst)); String fileContent = FileUtils.readFileToString(new File(localSrc), "GBK"); outputStream.write(fileContent.getBytes()); outputStream.close(); long end = new Date().getTime(); System.out.println("use:"+(end-start)); }

下面是本身新建的项目：apache

public static void main(String[] args) { Configuration conf = new Configuration(); conf.set("fs.defaultFS", "hdfs://hadoop-ha"); conf.set("dfs.nameservices", "hadoop-ha"); conf.set("dfs.ha.namenodes.hadoop-ha", "nn1,nn2"); conf.set("dfs.namenode.rpc-address.hadoop-ha.nn1", "bigdata-pro01.mars.com:8020"); conf.set("dfs.namenode.rpc-address.hadoop-ha.nn2", "bigdata-pro02.mars.com:8020"); conf.set("dfs.client.failover.proxy.provider.hadoop-ha", "org.apache.hadoop.hdfs.server.namenode.ha.ConfiguredFailoverProxyProvider"); FileSystem fs = null; try { fs = FileSystem.get(conf); FileStatus[] list = fs.listStatus(new Path("/user/bigdata/hdfs/core-site.xml")); for (FileStatus file : list) { System.out.println(file.getPath().getName().getBytes()); } } catch (IOException e) { e.printStackTrace(); } finally { try { fs.close(); } catch (IOException e) { e.printStackTrace(); } } }