本文整理汇总了Java中org.apache.hadoop.hdfs.MiniDFSCluster.readBlockOnDataNode方法的典型用法代码示例。如果您正苦于以下问题：Java MiniDFSCluster.readBlockOnDataNode方法的具体用法？Java MiniDFSCluster.readBlockOnDataNode怎么用？Java MiniDFSCluster.readBlockOnDataNode使用的例子？那么, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在类org.apache.hadoop.hdfs.MiniDFSCluster的用法示例。
在下文中一共展示了MiniDFSCluster.readBlockOnDataNode方法的1个代码示例，这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞，您的评价将有助于系统推荐出更棒的Java代码示例。
示例1: testCorruptBlockRereplicatedAcrossRacks
import org.apache.hadoop.hdfs.MiniDFSCluster; //导入方法依赖的package包/类
@Test
public void testCorruptBlockRereplicatedAcrossRacks() throws Exception {
Configuration conf = getConf();
short REPLICATION_FACTOR = 2;
int fileLen = 512;
final Path filePath = new Path("/testFile");
// Datanodes are spread across two racks
String racks[] = {"/rack1", "/rack1", "/rack2", "/rack2"};
MiniDFSCluster cluster = new MiniDFSCluster.Builder(conf)
.numDataNodes(racks.length).racks(racks).build();
final FSNamesystem ns = cluster.getNameNode().getNamesystem();
try {
// Create a file with one block with a replication factor of 2
final FileSystem fs = cluster.getFileSystem();
DFSTestUtil.createFile(fs, filePath, fileLen, REPLICATION_FACTOR, 1L);
final String fileContent = DFSTestUtil.readFile(fs, filePath);
ExtendedBlock b = DFSTestUtil.getFirstBlock(fs, filePath);
DFSTestUtil.waitForReplication(cluster, b, 2, REPLICATION_FACTOR, 0);
// Corrupt a replica of the block
int dnToCorrupt = DFSTestUtil.firstDnWithBlock(cluster, b);
assertTrue(cluster.corruptReplica(dnToCorrupt, b));
// Restart the datanode so blocks are re-scanned, and the corrupt
// block is detected.
cluster.restartDataNode(dnToCorrupt);
// Wait for the namenode to notice the corrupt replica
DFSTestUtil.waitCorruptReplicas(fs, ns, filePath, b, 1);
// The rack policy is still respected
DFSTestUtil.waitForReplication(cluster, b, 2, REPLICATION_FACTOR, 0);
// Ensure all replicas are valid (the corrupt replica may not
// have been cleaned up yet).
for (int i = 0; i < racks.length; i++) {
String blockContent = cluster.readBlockOnDataNode(i, b);
if (blockContent != null && i != dnToCorrupt) {
assertEquals("Corrupt replica", fileContent, blockContent);
}
}
} finally {
cluster.shutdown();
}
}