Java tutorial
/** * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you under the Apache License, Version 2.0 (the * "License"); you may not use this file except in compliance * with the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, * software distributed under the License is distributed on an * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY * KIND, either express or implied. See the License for the * specific language governing permissions and limitations * under the License. */ package org.apache.hive.hcatalog.api.repl.commands; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.apache.hadoop.fs.FileSystem; import org.apache.hadoop.fs.Path; import org.apache.hadoop.hive.cli.CliSessionState; import org.apache.hadoop.hive.conf.HiveConf; import org.apache.hadoop.hive.metastore.api.MetaException; import org.apache.hadoop.hive.ql.CommandNeedRetryException; import org.apache.hadoop.hive.ql.Driver; import org.apache.hadoop.hive.ql.processors.CommandProcessorResponse; import org.apache.hadoop.hive.ql.session.SessionState; import org.apache.hive.hcatalog.HcatTestUtils; import org.apache.hive.hcatalog.api.HCatAddPartitionDesc; import org.apache.hive.hcatalog.api.HCatClient; import org.apache.hive.hcatalog.api.HCatCreateDBDesc; import org.apache.hive.hcatalog.api.HCatCreateTableDesc; import org.apache.hive.hcatalog.api.HCatDatabase; import org.apache.hive.hcatalog.api.HCatPartition; import org.apache.hive.hcatalog.api.HCatTable; import org.apache.hive.hcatalog.api.ObjectNotFoundException; import org.apache.hive.hcatalog.api.TestHCatClient; import org.apache.hive.hcatalog.api.repl.Command; import org.apache.hive.hcatalog.api.repl.CommandTestUtils; import org.apache.hive.hcatalog.api.repl.ReplicationUtils; import org.apache.hive.hcatalog.common.HCatException; import org.apache.hive.hcatalog.data.schema.HCatFieldSchema; import org.apache.hive.hcatalog.data.schema.HCatSchemaUtils; import org.junit.AfterClass; import org.junit.BeforeClass; import org.junit.Test; import java.io.BufferedReader; import java.io.File; import java.io.IOException; import java.io.InputStreamReader; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map; import static org.junit.Assert.assertEquals; import static org.junit.Assert.assertNotNull; import static org.junit.Assert.assertTrue; public class TestCommands { private static Logger LOG = LoggerFactory.getLogger(CommandTestUtils.class.getName()); private static HiveConf hconf; private static Driver driver; private static HCatClient client; private static String TEST_PATH; @BeforeClass public static void setUpBeforeClass() throws Exception { TestHCatClient.startMetaStoreServer(); hconf = TestHCatClient.getConf(); hconf.set(HiveConf.ConfVars.SEMANTIC_ANALYZER_HOOK.varname, ""); hconf.setVar(HiveConf.ConfVars.HIVE_AUTHORIZATION_MANAGER, "org.apache.hadoop.hive.ql.security.authorization.plugin.sqlstd.SQLStdHiveAuthorizerFactory"); TEST_PATH = System.getProperty("test.warehouse.dir", "/tmp") + Path.SEPARATOR + TestCommands.class.getCanonicalName() + "-" + System.currentTimeMillis(); Path testPath = new Path(TEST_PATH); FileSystem fs = FileSystem.get(testPath.toUri(), hconf); fs.mkdirs(testPath); driver = new Driver(hconf); SessionState.start(new CliSessionState(hconf)); client = HCatClient.create(hconf); } @AfterClass public static void tearDownAfterClass() throws Exception { TestHCatClient.tearDown(); } @Test public void testDropDatabaseCommand() throws HCatException, CommandNeedRetryException { String dbName = "cmd_testdb"; int evid = 999; Command testCmd = new DropDatabaseCommand(dbName, evid); assertEquals(evid, testCmd.getEventId()); assertEquals(1, testCmd.get().size()); assertEquals(true, testCmd.isRetriable()); assertEquals(false, testCmd.isUndoable()); CommandTestUtils.testCommandSerialization(testCmd); client.dropDatabase(dbName, true, HCatClient.DropDBMode.CASCADE); client.createDatabase(HCatCreateDBDesc.create(dbName).ifNotExists(false).build()); HCatDatabase db = client.getDatabase(dbName); assertNotNull(db); LOG.info("About to run :" + testCmd.get().get(0)); driver.run(testCmd.get().get(0)); Exception onfe = null; try { HCatDatabase db_del = client.getDatabase(dbName); } catch (Exception e) { onfe = e; } assertNotNull(onfe); assertTrue(onfe instanceof ObjectNotFoundException); } @Test public void testDropTableCommand() throws HCatException, CommandNeedRetryException { String dbName = "cmd_testdb"; String tableName = "cmd_testtable"; int evid = 789; List<HCatFieldSchema> cols = HCatSchemaUtils.getHCatSchema("a:int,b:string").getFields(); Command testReplicatedDropCmd = new DropTableCommand(dbName, tableName, true, evid); assertEquals(evid, testReplicatedDropCmd.getEventId()); assertEquals(1, testReplicatedDropCmd.get().size()); assertEquals(true, testReplicatedDropCmd.isRetriable()); assertEquals(false, testReplicatedDropCmd.isUndoable()); CommandTestUtils.testCommandSerialization(testReplicatedDropCmd); Command testNormalDropCmd = new DropTableCommand(dbName, tableName, false, evid); assertEquals(evid, testNormalDropCmd.getEventId()); assertEquals(1, testNormalDropCmd.get().size()); assertEquals(true, testNormalDropCmd.isRetriable()); assertEquals(false, testNormalDropCmd.isUndoable()); CommandTestUtils.testCommandSerialization(testNormalDropCmd); client.dropDatabase(dbName, true, HCatClient.DropDBMode.CASCADE); client.createDatabase(HCatCreateDBDesc.create(dbName).ifNotExists(false).build()); Map<String, String> tprops = new HashMap<String, String>(); tprops.put(ReplicationUtils.REPL_STATE_ID, String.valueOf(evid + 5)); HCatTable tableToCreate = (new HCatTable(dbName, tableName)).tblProps(tprops).cols(cols); client.createTable(HCatCreateTableDesc.create(tableToCreate).build()); HCatTable t1 = client.getTable(dbName, tableName); assertNotNull(t1); // Test replicated drop, should not drop, because evid < repl.state.id LOG.info("About to run :" + testReplicatedDropCmd.get().get(0)); driver.run(testReplicatedDropCmd.get().get(0)); HCatTable t2 = client.getTable(dbName, tableName); assertNotNull(t2); // Test normal drop, should drop unconditionally. LOG.info("About to run :" + testNormalDropCmd.get().get(0)); driver.run(testNormalDropCmd.get().get(0)); Exception onfe = null; try { HCatTable t_del = client.getTable(dbName, tableName); } catch (Exception e) { onfe = e; } assertNotNull(onfe); assertTrue(onfe instanceof ObjectNotFoundException); Map<String, String> tprops2 = new HashMap<String, String>(); tprops2.put(ReplicationUtils.REPL_STATE_ID, String.valueOf(evid - 5)); HCatTable tableToCreate2 = (new HCatTable(dbName, tableName)).tblProps(tprops2).cols(cols); client.createTable(HCatCreateTableDesc.create(tableToCreate2).build()); HCatTable t3 = client.getTable(dbName, tableName); assertNotNull(t3); // Test replicated drop, should drop this time, since repl.state.id < evid. LOG.info("About to run :" + testReplicatedDropCmd.get().get(0)); driver.run(testReplicatedDropCmd.get().get(0)); Exception onfe2 = null; try { HCatTable t_del = client.getTable(dbName, tableName); } catch (Exception e) { onfe2 = e; } assertNotNull(onfe2); assertTrue(onfe2 instanceof ObjectNotFoundException); } @Test public void testDropPartitionCommand() throws HCatException, CommandNeedRetryException, MetaException { String dbName = "cmd_testdb"; String tableName = "cmd_testtable"; int evid = 789; List<HCatFieldSchema> pcols = HCatSchemaUtils.getHCatSchema("b:string").getFields(); List<HCatFieldSchema> cols = HCatSchemaUtils.getHCatSchema("a:int").getFields(); Map<String, String> ptnDesc = new HashMap<String, String>(); ptnDesc.put("b", "test"); Command testReplicatedDropPtnCmd = new DropPartitionCommand(dbName, tableName, ptnDesc, true, evid); assertEquals(evid, testReplicatedDropPtnCmd.getEventId()); assertEquals(1, testReplicatedDropPtnCmd.get().size()); assertEquals(true, testReplicatedDropPtnCmd.isRetriable()); assertEquals(false, testReplicatedDropPtnCmd.isUndoable()); CommandTestUtils.testCommandSerialization(testReplicatedDropPtnCmd); Command testNormalDropPtnCmd = new DropPartitionCommand(dbName, tableName, ptnDesc, false, evid); assertEquals(evid, testNormalDropPtnCmd.getEventId()); assertEquals(1, testNormalDropPtnCmd.get().size()); assertEquals(true, testNormalDropPtnCmd.isRetriable()); assertEquals(false, testNormalDropPtnCmd.isUndoable()); CommandTestUtils.testCommandSerialization(testNormalDropPtnCmd); client.dropDatabase(dbName, true, HCatClient.DropDBMode.CASCADE); client.createDatabase(HCatCreateDBDesc.create(dbName).ifNotExists(false).build()); Map<String, String> props = new HashMap<String, String>(); props.put(ReplicationUtils.REPL_STATE_ID, String.valueOf(evid + 5)); HCatTable table = (new HCatTable(dbName, tableName)).tblProps(props).cols(cols).partCols(pcols); client.createTable(HCatCreateTableDesc.create(table).build()); HCatTable tableCreated = client.getTable(dbName, tableName); assertNotNull(tableCreated); HCatPartition ptnToAdd = (new HCatPartition(tableCreated, ptnDesc, TestHCatClient.makePartLocation(tableCreated, ptnDesc))).parameters(props); client.addPartition(HCatAddPartitionDesc.create(ptnToAdd).build()); HCatPartition p1 = client.getPartition(dbName, tableName, ptnDesc); assertNotNull(p1); // Test replicated drop, should not drop, because evid < repl.state.id LOG.info("About to run :" + testReplicatedDropPtnCmd.get().get(0)); driver.run(testReplicatedDropPtnCmd.get().get(0)); HCatPartition p2 = client.getPartition(dbName, tableName, ptnDesc); assertNotNull(p2); // Test normal drop, should drop unconditionally. LOG.info("About to run :" + testNormalDropPtnCmd.get().get(0)); driver.run(testNormalDropPtnCmd.get().get(0)); Exception onfe = null; try { HCatPartition p_del = client.getPartition(dbName, tableName, ptnDesc); } catch (Exception e) { onfe = e; } assertNotNull(onfe); assertTrue(onfe instanceof ObjectNotFoundException); Map<String, String> props2 = new HashMap<String, String>(); props2.put(ReplicationUtils.REPL_STATE_ID, String.valueOf(evid - 5)); HCatPartition ptnToAdd2 = (new HCatPartition(tableCreated, ptnDesc, TestHCatClient.makePartLocation(tableCreated, ptnDesc))).parameters(props2); client.addPartition(HCatAddPartitionDesc.create(ptnToAdd2).build()); HCatPartition p3 = client.getPartition(dbName, tableName, ptnDesc); assertNotNull(p3); // Test replicated drop, should drop this time, since repl.state.id < evid. LOG.info("About to run :" + testReplicatedDropPtnCmd.get().get(0)); driver.run(testReplicatedDropPtnCmd.get().get(0)); Exception onfe2 = null; try { HCatPartition p_del = client.getPartition(dbName, tableName, ptnDesc); } catch (Exception e) { onfe2 = e; } assertNotNull(onfe2); assertTrue(onfe2 instanceof ObjectNotFoundException); } @Test public void testDropTableCommand2() throws HCatException, CommandNeedRetryException, MetaException { // Secondary DropTableCommand test for testing repl-drop-tables' effect on partitions inside a partitioned table // when there exist partitions inside the table which are older than the drop event. // Our goal is this : Create a table t, with repl.last.id=157, say. // Create 2 partitions inside it, with repl.last.id=150 and 160, say. // Now, process a drop table command with eventid=155. // It should result in the table and the partition with repl.last.id=160 continuing to exist, // but dropping the partition with repl.last.id=150. String dbName = "cmd_testdb"; String tableName = "cmd_testtable"; int evid = 157; List<HCatFieldSchema> pcols = HCatSchemaUtils.getHCatSchema("b:string").getFields(); List<HCatFieldSchema> cols = HCatSchemaUtils.getHCatSchema("a:int").getFields(); Command testReplicatedDropCmd = new DropTableCommand(dbName, tableName, true, evid); client.dropDatabase(dbName, true, HCatClient.DropDBMode.CASCADE); client.createDatabase(HCatCreateDBDesc.create(dbName).ifNotExists(false).build()); Map<String, String> tprops = new HashMap<String, String>(); tprops.put(ReplicationUtils.REPL_STATE_ID, String.valueOf(evid + 2)); HCatTable table = (new HCatTable(dbName, tableName)).tblProps(tprops).cols(cols).partCols(pcols); client.createTable(HCatCreateTableDesc.create(table).build()); HCatTable tableCreated = client.getTable(dbName, tableName); assertNotNull(tableCreated); Map<String, String> ptnDesc1 = new HashMap<String, String>(); ptnDesc1.put("b", "test-older"); Map<String, String> props1 = new HashMap<String, String>(); props1.put(ReplicationUtils.REPL_STATE_ID, String.valueOf(evid - 5)); HCatPartition ptnToAdd1 = (new HCatPartition(tableCreated, ptnDesc1, TestHCatClient.makePartLocation(tableCreated, ptnDesc1))).parameters(props1); client.addPartition(HCatAddPartitionDesc.create(ptnToAdd1).build()); Map<String, String> ptnDesc2 = new HashMap<String, String>(); ptnDesc2.put("b", "test-newer"); Map<String, String> props2 = new HashMap<String, String>(); props2.put(ReplicationUtils.REPL_STATE_ID, String.valueOf(evid + 5)); HCatPartition ptnToAdd2 = (new HCatPartition(tableCreated, ptnDesc2, TestHCatClient.makePartLocation(tableCreated, ptnDesc2))).parameters(props2); client.addPartition(HCatAddPartitionDesc.create(ptnToAdd2).build()); HCatPartition p1 = client.getPartition(dbName, tableName, ptnDesc1); assertNotNull(p1); HCatPartition p2 = client.getPartition(dbName, tableName, ptnDesc2); assertNotNull(p2); LOG.info("About to run :" + testReplicatedDropCmd.get().get(0)); driver.run(testReplicatedDropCmd.get().get(0)); HCatTable t_stillExists = client.getTable(dbName, tableName); assertNotNull(t_stillExists); HCatPartition p2_stillExists = client.getPartition(dbName, tableName, ptnDesc2); Exception onfe = null; try { HCatPartition p1_del = client.getPartition(dbName, tableName, ptnDesc1); } catch (Exception e) { onfe = e; } assertNotNull(onfe); assertTrue(onfe instanceof ObjectNotFoundException); } @Test public void testBasicReplEximCommands() throws IOException, CommandNeedRetryException { // repl export, has repl.last.id and repl.scope=all in it // import repl dump, table has repl.last.id on it (will likely be 0) int evid = 111; String exportLocation = TEST_PATH + File.separator + "testBasicReplExim"; Path tempPath = new Path(TEST_PATH, "testBasicReplEximTmp"); String tempLocation = tempPath.toUri().getPath(); String dbName = "exim"; String tableName = "basicSrc"; String importedTableName = "basicDst"; List<HCatFieldSchema> cols = HCatSchemaUtils.getHCatSchema("b:string").getFields(); client.dropDatabase(dbName, true, HCatClient.DropDBMode.CASCADE); client.createDatabase(HCatCreateDBDesc.create(dbName).ifNotExists(false).build()); HCatTable table = (new HCatTable(dbName, tableName)).cols(cols).fileFormat("textfile"); client.createTable(HCatCreateTableDesc.create(table).build()); HCatTable t = client.getTable(dbName, tableName); assertNotNull(t); String[] data = new String[] { "eleven", "twelve" }; HcatTestUtils.createTestDataFile(tempLocation, data); CommandProcessorResponse ret = driver.run( "LOAD DATA LOCAL INPATH '" + tempLocation + "' OVERWRITE INTO TABLE " + dbName + "." + tableName); assertEquals(ret.getResponseCode() + ":" + ret.getErrorMessage(), null, ret.getException()); CommandProcessorResponse selectRet = driver.run("SELECT * from " + dbName + "." + tableName); assertEquals(selectRet.getResponseCode() + ":" + selectRet.getErrorMessage(), null, selectRet.getException()); List<String> values = new ArrayList<String>(); driver.getResults(values); assertEquals(2, values.size()); assertEquals(data[0], values.get(0)); assertEquals(data[1], values.get(1)); ExportCommand exportCmd = new ExportCommand(dbName, tableName, null, exportLocation, false, evid); LOG.info("About to run :" + exportCmd.get().get(0)); CommandProcessorResponse ret2 = driver.run(exportCmd.get().get(0)); assertEquals(ret2.getResponseCode() + ":" + ret2.getErrorMessage(), null, ret2.getException()); List<String> exportPaths = exportCmd.cleanupLocationsAfterEvent(); assertEquals(1, exportPaths.size()); String metadata = getMetadataContents(exportPaths.get(0)); LOG.info("Export returned the following _metadata contents:"); LOG.info(metadata); assertTrue(metadata + "did not match \"repl.scope\"=\"all\"", metadata.matches(".*\"repl.scope\":\"all\".*")); assertTrue(metadata + "has \"repl.last.id\"", metadata.matches(".*\"repl.last.id\":.*")); ImportCommand importCmd = new ImportCommand(dbName, importedTableName, null, exportLocation, false, evid); LOG.info("About to run :" + importCmd.get().get(0)); CommandProcessorResponse ret3 = driver.run(importCmd.get().get(0)); assertEquals(ret3.getResponseCode() + ":" + ret3.getErrorMessage(), null, ret3.getException()); CommandProcessorResponse selectRet2 = driver.run("SELECT * from " + dbName + "." + importedTableName); assertEquals(selectRet2.getResponseCode() + ":" + selectRet2.getErrorMessage(), null, selectRet2.getException()); List<String> values2 = new ArrayList<String>(); driver.getResults(values2); assertEquals(2, values2.size()); assertEquals(data[0], values2.get(0)); assertEquals(data[1], values2.get(1)); HCatTable importedTable = client.getTable(dbName, importedTableName); assertNotNull(importedTable); assertTrue(importedTable.getTblProps().containsKey("repl.last.id")); } @Test public void testMetadataReplEximCommands() throws IOException, CommandNeedRetryException { // repl metadata export, has repl.last.id and repl.scope=metadata // import repl metadata dump, table metadata changed, allows override, has repl.last.id int evid = 222; String exportLocation = TEST_PATH + File.separator + "testMetadataReplExim"; Path tempPath = new Path(TEST_PATH, "testMetadataReplEximTmp"); String tempLocation = tempPath.toUri().getPath(); String dbName = "exim"; String tableName = "basicSrc"; String importedTableName = "basicDst"; List<HCatFieldSchema> cols = HCatSchemaUtils.getHCatSchema("b:string").getFields(); client.dropDatabase(dbName, true, HCatClient.DropDBMode.CASCADE); client.createDatabase(HCatCreateDBDesc.create(dbName).ifNotExists(false).build()); HCatTable table = (new HCatTable(dbName, tableName)).cols(cols).fileFormat("textfile"); client.createTable(HCatCreateTableDesc.create(table).build()); HCatTable t = client.getTable(dbName, tableName); assertNotNull(t); String[] data = new String[] { "eleven", "twelve" }; HcatTestUtils.createTestDataFile(tempLocation, data); CommandProcessorResponse ret = driver.run( "LOAD DATA LOCAL INPATH '" + tempLocation + "' OVERWRITE INTO TABLE " + dbName + "." + tableName); assertEquals(ret.getResponseCode() + ":" + ret.getErrorMessage(), null, ret.getException()); CommandProcessorResponse selectRet = driver.run("SELECT * from " + dbName + "." + tableName); assertEquals(selectRet.getResponseCode() + ":" + selectRet.getErrorMessage(), null, selectRet.getException()); List<String> values = new ArrayList<String>(); driver.getResults(values); assertEquals(2, values.size()); assertEquals(data[0], values.get(0)); assertEquals(data[1], values.get(1)); ExportCommand exportMdCmd = new ExportCommand(dbName, tableName, null, exportLocation, true, evid); LOG.info("About to run :" + exportMdCmd.get().get(0)); CommandProcessorResponse ret2 = driver.run(exportMdCmd.get().get(0)); assertEquals(ret2.getResponseCode() + ":" + ret2.getErrorMessage(), null, ret2.getException()); List<String> exportPaths = exportMdCmd.cleanupLocationsAfterEvent(); assertEquals(1, exportPaths.size()); String metadata = getMetadataContents(exportPaths.get(0)); LOG.info("Export returned the following _metadata contents:"); LOG.info(metadata); assertTrue(metadata + "did not match \"repl.scope\"=\"metadata\"", metadata.matches(".*\"repl.scope\":\"metadata\".*")); assertTrue(metadata + "has \"repl.last.id\"", metadata.matches(".*\"repl.last.id\":.*")); ImportCommand importMdCmd = new ImportCommand(dbName, importedTableName, null, exportLocation, true, evid); LOG.info("About to run :" + importMdCmd.get().get(0)); CommandProcessorResponse ret3 = driver.run(importMdCmd.get().get(0)); assertEquals(ret3.getResponseCode() + ":" + ret3.getErrorMessage(), null, ret3.getException()); CommandProcessorResponse selectRet2 = driver.run("SELECT * from " + dbName + "." + importedTableName); assertEquals(selectRet2.getResponseCode() + ":" + selectRet2.getErrorMessage(), null, selectRet2.getException()); List<String> values2 = new ArrayList<String>(); driver.getResults(values2); assertEquals(0, values2.size()); HCatTable importedTable = client.getTable(dbName, importedTableName); assertNotNull(importedTable); assertTrue(importedTable.getTblProps().containsKey("repl.last.id")); } @Test public void testNoopReplEximCommands() throws CommandNeedRetryException, IOException { // repl noop export on non-existant table, has repl.noop, does not error // import repl noop dump, no error int evid = 333; String exportLocation = TEST_PATH + File.separator + "testNoopReplExim"; String dbName = "doesNotExist" + System.currentTimeMillis(); String tableName = "nope" + System.currentTimeMillis(); ExportCommand noopExportCmd = new ExportCommand(dbName, tableName, null, exportLocation, false, evid); LOG.info("About to run :" + noopExportCmd.get().get(0)); CommandProcessorResponse ret = driver.run(noopExportCmd.get().get(0)); assertEquals(ret.getResponseCode() + ":" + ret.getErrorMessage(), null, ret.getException()); List<String> exportPaths = noopExportCmd.cleanupLocationsAfterEvent(); assertEquals(1, exportPaths.size()); String metadata = getMetadataContents(exportPaths.get(0)); LOG.info("Export returned the following _metadata contents:"); LOG.info(metadata); assertTrue(metadata + "did not match \"repl.noop\"=\"true\"", metadata.matches(".*\"repl.noop\":\"true\".*")); ImportCommand noopImportCmd = new ImportCommand(dbName, tableName, null, exportLocation, false, evid); LOG.info("About to run :" + noopImportCmd.get().get(0)); CommandProcessorResponse ret2 = driver.run(noopImportCmd.get().get(0)); assertEquals(ret2.getResponseCode() + ":" + ret2.getErrorMessage(), null, ret2.getException()); Exception onfe = null; try { HCatDatabase d_doesNotExist = client.getDatabase(dbName); } catch (Exception e) { onfe = e; } assertNotNull(onfe); assertTrue(onfe instanceof ObjectNotFoundException); } private static String getMetadataContents(String exportPath) throws IOException { Path mdFilePath = new Path(exportPath, "_metadata"); FileSystem fs = FileSystem.get(mdFilePath.toUri(), hconf); assertTrue(mdFilePath.toUri().toString() + "does not exist", fs.exists(mdFilePath)); BufferedReader reader = new BufferedReader(new InputStreamReader(fs.open(mdFilePath))); StringBuilder sb = new StringBuilder(); String line; while ((line = reader.readLine()) != null) { sb.append(line); } reader.close(); return sb.toString(); } }