Java项目连接hbase时超时

本人小白一枚,现在有个项目是用Java项目连接hbase。我用的是windows下的Java项目连接linux虚拟机上的hbase,hbase开启之后连接提示连接超时(ps:主机之间可互通),求助。。。
log4j:WARN No appenders could be found for logger (org.apache.hadoop.util.Shell).
log4j:WARN Please initialize the log4j system properly.
SLF4J: Class path contains multiple SLF4J bindings.
SLF4J: Found binding in [jar:file:/E:/apache-tomcat-7.0.85-windows-x64/apache-tomcat-7.0.85/webapps/car_hbase/WEB-INF/lib/slf4j-log4j12-1.5.8.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: Found binding in [jar:file:/E:/apache-tomcat-7.0.85-windows-x64/apache-tomcat-7.0.85/webapps/car_hbase/WEB-INF/lib/slf4j-log4j12-1.7.10.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: See http://www.slf4j.org/codes.html#multiple_bindings for an explanation.
e785dc9437424bf8a7714f460293896c HBASE表创建失败!
java.io.IOException: Failed to get result within timeout, timeout=60000ms
at org.apache.hadoop.hbase.client.ScannerCallableWithReplicas.call(ScannerCallableWithReplicas.java:232)
at org.apache.hadoop.hbase.client.ScannerCallableWithReplicas.call(ScannerCallableWithReplicas.java:58)
at org.apache.hadoop.hbase.client.RpcRetryingCaller.callWithoutRetries(RpcRetryingCaller.java:219)
at org.apache.hadoop.hbase.client.ClientScanner.call(ClientScanner.java:277)
at org.apache.hadoop.hbase.client.ClientScanner.loadCache(ClientScanner.java:438)
at org.apache.hadoop.hbase.client.ClientScanner.next(ClientScanner.java:312)
at org.apache.hadoop.hbase.MetaTableAccessor.fullScan(MetaTableAccessor.java:604)
at org.apache.hadoop.hbase.MetaTableAccessor.tableExists(MetaTableAccessor.java:366)
at org.apache.hadoop.hbase.client.HBaseAdmin.tableExists(HBaseAdmin.java:410)
at org.apache.hadoop.hbase.client.HBaseAdmin.tableExists(HBaseAdmin.java:420)
at util.HBaseUtil.createTable(HBaseUtil.java:45)
at util.HbaseDemo.createTable(HbaseDemo.java:55)
at util.StartupListener.contextInitialized(StartupListener.java:31)
at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:5118)
at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5641)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)
at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:1015)
at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:991)
at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:652)
at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.java:1296)
at org.apache.catalina.startup.HostConfig$DeployDirectory.run(HostConfig.java:2038)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)

5个回答

看主机名是不是无法识别,是否需要添加映射

可能dns解析不对,windows的hosts文件添加:x.x.x.x localhost.localdomain映射试试,x.x.x.x是linux的IP

windows的hosts文件有配置master-slave吗

加入配置文件<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>


hbase.zookeeper.quorum
master,slave1,slave2


hbase.zookeeper.property.clientPort
2181


然后public static final Configuration CONFIGURATION=HBaseConfiguration.create();获取配置

配置的时候可能是hbase的路径不对,你看下你设置的是不是默认地址,我之前遇到连不上也是用了默认的地址,然后发现我自己的不是

Csdn user default icon
上传中...
上传图片
插入图片
抄袭、复制答案,以达到刷声望分或其他目的的行为,在CSDN问答是严格禁止的,一经发现立刻封号。是时候展现真正的技术了!
其他相关推荐
使用Java对hbase进行连接测试,连接不上,超时,

我在Linux上安装了hbase的单机版,hbase版本是1.2.6, zookeeper使用的是hbase自己的,Linux防火墙开放了16010和2181端口, 使用hbase shell 可以正常操作hbase,浏览器也可以正常访问hbase, 但是我使用Java对hbase进行连接测试的时候就是一直连接不上,然后当我关闭 Linux防火墙的时候java又可以正常的对hbase进行连接访问了,???,这是怎么回事,是因为Linux防火墙还需要开放其他端口吗

JAVA连接Hbase集群

java连接Hbase,代码卡在 HBaseAdmin admin1 = new HBaseAdmin(conf1);处

java连接单机hbase操作数据

16/03/04 17:09:56 INFO support.ClassPathXmlApplicationContext: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@1f6ae4d: startup date [Fri Mar 04 17:09:56 CST 2016]; root of context hierarchy 16/03/04 17:09:56 INFO xml.XmlBeanDefinitionReader: Loading XML bean definitions from class path resource [applicationContest.xml] 16/03/04 17:09:57 INFO support.DefaultListableBeanFactory: Pre-instantiating singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory@1d8fe20: defining beans [hbaseConfiguration,htemplate]; root of factory hierarchy 16/03/04 17:09:57 WARN util.NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable 16/03/04 17:09:57 INFO zookeeper.RecoverableZooKeeper: Process identifier=hconnection-0xc4dc7c connecting to ZooKeeper ensemble=192.168.1.202:2181 16/03/04 17:09:57 INFO zookeeper.ZooKeeper: Client environment:zookeeper.version=3.4.5-cdh5.2.0--1, built on 10/11/2014 20:49 GMT 16/03/04 17:09:57 INFO zookeeper.ZooKeeper: Client environment:host.name=xiaoming 16/03/04 17:09:57 INFO zookeeper.ZooKeeper: Client environment:java.version=1.7.0_17 16/03/04 17:09:57 INFO zookeeper.ZooKeeper: Client environment:java.vendor=Oracle Corporation 16/03/04 17:09:57 INFO zookeeper.ZooKeeper: Client environment:java.home=C:\Program Files (x86)\Java\jdk1.7.0_17\jre 16/03/04 17:09:57 INFO zookeeper.ZooKeeper: Client environment:java.class.path=F:\mess\12Hadoop\workspace\myhbasetest\WebRoot\WEB-INF\classes;F:\mess\12Hadoop\workspace\myhbasetest\WebRoot\WEB-INF\lib\commons-codec-1.7.jar;F:\mess\12Hadoop\workspace\myhbasetest\WebRoot\WEB-INF\lib\commons-collections-3.2.1.jar;F:\mess\12Hadoop\workspace\myhbasetest\WebRoot\WEB-INF\lib\commons-configuration-1.6.jar;F:\mess\12Hadoop\workspace\myhbasetest\WebRoot\WEB-INF\lib\commons-lang-2.6.jar;F:\mess\12Hadoop\workspace\myhbasetest\WebRoot\WEB-INF\lib\commons-logging-1.1.1.jar;F:\mess\12Hadoop\workspace\myhbasetest\WebRoot\WEB-INF\lib\guava-12.0.1.jar;F:\mess\12Hadoop\workspace\myhbasetest\WebRoot\WEB-INF\lib\hadoop-auth-2.5.0-cdh5.2.0.jar;F:\mess\12Hadoop\workspace\myhbasetest\WebRoot\WEB-INF\lib\hadoop-common-2.5.0-cdh5.2.0.jar;F:\mess\12Hadoop\workspace\myhbasetest\WebRoot\WEB-INF\lib\hadoop-core-2.5.0-mr1-cdh5.2.0.jar;F:\mess\12Hadoop\workspace\myhbasetest\WebRoot\WEB-INF\lib\hbase-client-0.98.6-cdh5.2.0.jar;F:\mess\12Hadoop\workspace\myhbasetest\WebRoot\WEB-INF\lib\hbase-common-0.98.6-cdh5.2.0.jar;F:\mess\12Hadoop\workspace....... 16/03/04 17:09:57 INFO zookeeper.ClientCnxn: Opening socket connection to server 192.168.1.202/192.168.1.202:2181. Will not attempt to authenticate using SASL (unknown error) 16/03/04 17:09:57 INFO zookeeper.ClientCnxn: Socket connection established to 192.168.1.202/192.168.1.202:2181, initiating session 16/03/04 17:09:57 INFO zookeeper.ClientCnxn: Session establishment complete on server 192.168.1.202/192.168.1.202:2181, sessionid = 0x15341c9328d0012, negotiated timeout = 40000 16/03/04 17:17:50 WARN client.HConnectionManager$HConnectionImplementation: Encountered problems when prefetch hbase:meta table: org.apache.hadoop.hbase.client.RetriesExhaustedException: Failed after attempts=31, exceptions: .......Fri Mar 04 17:17:50 CST 2016, org.apache.hadoop.hbase.client.RpcRetryingCaller@b7b17a, java.net.UnknownHostException: unknown host: hbase ......at org.apache.hadoop.hbase.client.RpcRetryingCaller.callWithRetries(RpcRetryingCaller.java:129) at org.apache.hadoop.hbase.client.HTable.getRowOrBefore(HTable.java:714) at org.apache.hadoop.hbase.client.MetaScanner.metaScan(MetaScanner.java:144) at org.apache.hadoop.hbase.client.HConnectionManager$HConnectionImplementation.prefetchRegionCache(HConnectionManager.java:1140) at org.apache.hadoop.hbase.client.HConnectionManager$HConnectionImplementation.locateRegionInMeta(HConnectionManager.java:1204) at org.apache.hadoop.hbase.client.HConnectionManager$HConnectionImplementation.locateRegion(HConnectionManager.java:1092) at org.apache.hadoop.hbase.client.HConnectionManager$HConnectionImplementation.locateRegion(HConnectionManager.java:1049) at org.apache.hadoop.hbase.client.HConnectionManager$HConnectionImplementation.getRegionLocation(HConnectionManager.java:890) at org.apache.hadoop.hbase.client.RegionServerCallable.prepare(RegionServerCallable.java:72) at org.apache.hadoop.hbase.client.RpcRetryingCaller.callWithRetries(RpcRetryingCaller.java:113) at org.apache.hadoop.hbase.client.HTable.get(HTable.java:780) at org.springframework.data.hadoop.hbase.HbaseTemplate$2.doInTable(HbaseTemplate.java:182) at org.springframework.data.hadoop.hbase.HbaseTemplate.execute(HbaseTemplate.java:58) at org.springframework.data.hadoop.hbase.HbaseTemplate.get(HbaseTemplate.java:168) at org.springframework.data.hadoop.hbase.HbaseTemplate.get(HbaseTemplate.java:158) at com.bw.test.Mytest.get(Mytest.java:46) at com.bw.test.Mytest.main(Mytest.java:40) Caused by: java.net.UnknownHostException: unknown host: hbase at org.apache.hadoop.hbase.ipc.RpcClient$Connection.<init>(RpcClient.java:385) at org.apache.hadoop.hbase.ipc.RpcClient.createConnection(RpcClient.java:351) at org.apache.hadoop.hbase.ipc.RpcClient.getConnection(RpcClient.java:1530) at org.apache.hadoop.hbase.ipc.RpcClient.call(RpcClient.java:1442) at org.apache.hadoop.hbase.ipc.RpcClient.callBlockingMethod(RpcClient.java:1661) at org.apache.hadoop.hbase.ipc.RpcClient$BlockingRpcChannelImplementation.callBlockingMethod(RpcClient.java:1719) at org.apache.hadoop.hbase.protobuf.generated.ClientProtos$ClientService$BlockingStub.get(ClientProtos.java:29966) at org.apache.hadoop.hbase.protobuf.ProtobufUtil.getRowOrBefore(ProtobufUtil.java:1562) at org.apache.hadoop.hbase.client.HTable$2.call(HTable.java:710) at org.apache.hadoop.hbase.client.HTable$2.call(HTable.java:708) at org.apache.hadoop.hbase.client.RpcRetryingCaller.callWithRetries(RpcRetryingCaller.java:114) ... 16 more

使用Java API访问hbase很慢的问题

有没有人出现过这种情况,就是使用java对HBASE进行连接的时候可以连接上,但是所花的时间都是20秒左右(不管是连接Linux上的HBASE还是自己windows上的HBASE都要20秒左右),不知道是什么原因导致的,时间都花在连接数据库上了,Java代码运行的时候也没有报任何的错误 habse安装的是单机版的,版本是1.2.6.1,zookeeper使用的是自带的,hadoop刚开始没有安装,后面安装了,但还是没什么作用,hosts文件这些都配置好了。 现在一个简单的增删改查都要花20秒钟,崩溃,被这个问题困扰了好几天了。。好难受,求大神帮忙解答啊。。

java连接hbase Kerberos 24小时报错问题

java连接hbase kerberos 24小时过期问题。求指点 ``` try { String krbStr = Thread.currentThread().getContextClassLoader().getResource("krb5.ini").getFile(); String keyStr = Thread.currentThread().getContextClassLoader().getResource(keytab).getFile(); System.setProperty("java.security.krb5.conf", krbStr); UserGroupInformation.setConfiguration(conf); UserGroupInformation.loginUserFromKeytab(principal, keyStr); } catch (IOException e) { log.error(e); } try { HBaseAdmin admin = new HBaseAdmin(conf); if (!admin.tableExists(tableName)) { HTableDescriptor tableDescripter = new HTableDescriptor( tableName.getBytes()); tableDescripter.addFamily(new HColumnDescriptor("data")); admin.createTable(tableDescripter); } } catch (Exception e) { log.error( e); } ``` 以上代码刚运行时没问题,但是过了24小时左右admin.tableExists(tableName)这句就会报错,错误如下 org.apache.hadoop.hbase.client.RetriesExhaustedException: Failed after attempts=36, exceptions: Sat Jul 13 14:30:29 CST 2019, null, java.net.SocketTimeoutException: callTimeout=60000, callDuration=68090: row 'p_rsdisk,,' on table 'hbase:meta' at region=hbase:meta,,1.1588230740, hostname=xx-xx-xx-xx-xx.indata.com,16020,1560266314048, seqNum=0 at org.apache.hadoop.hbase.client.RpcRetryingCallerWithReadReplicas.throwEnrichedException(RpcRetryingCallerWithReadReplicas.java:271) at org.apache.hadoop.hbase.client.ScannerCallableWithReplicas.call(ScannerCallableWithReplicas.java:223) at org.apache.hadoop.hbase.client.ScannerCallableWithReplicas.call(ScannerCallableWithReplicas.java:61) at org.apache.hadoop.hbase.client.RpcRetryingCaller.callWithoutRetries(RpcRetryingCaller.java:200) at org.apache.hadoop.hbase.client.ClientScanner.call(ClientScanner.java:320) at org.apache.hadoop.hbase.client.ClientScanner.nextScanner(ClientScanner.java:295) at org.apache.hadoop.hbase.client.ClientScanner.initializeScannerInConstruction(ClientScanner.java:160) at org.apache.hadoop.hbase.client.ClientScanner.<init>(ClientScanner.java:155) at org.apache.hadoop.hbase.client.HTable.getScanner(HTable.java:811) at org.apache.hadoop.hbase.MetaTableAccessor.fullScan(MetaTableAccessor.java:602) at org.apache.hadoop.hbase.MetaTableAccessor.tableExists(MetaTableAccessor.java:366) at org.apache.hadoop.hbase.client.HBaseAdmin.tableExists(HBaseAdmin.java:303) at org.apache.hadoop.hbase.client.HBaseAdmin.tableExists(HBaseAdmin.java:313) at javax.servlet.http.HttpServlet.service(HttpServlet.java:731) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208) at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208) at org.apache.catalina.filters.CorsFilter.handleNonCORS(CorsFilter.java:436) at org.apache.catalina.filters.CorsFilter.doFilter(CorsFilter.java:177) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:505) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:170) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103) at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:956) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:423) at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1079) at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:625) at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:316) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.lang.Thread.run(Thread.java:748) Caused by: java.net.SocketTimeoutException: callTimeout=60000, callDuration=68090: row 'p_rsdisk,,' on table 'hbase:meta' at region=hbase:meta,,1.1588230740, hostname=xx-xx-xx-xx-xx.indata.com,16020,1560266314048, seqNum=0 at org.apache.hadoop.hbase.client.RpcRetryingCaller.callWithRetries(RpcRetryingCaller.java:159) at org.apache.hadoop.hbase.client.ResultBoundedCompletionService$QueueingFuture.run(ResultBoundedCompletionService.java:64) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) ... 1 more Caused by: java.io.IOException: Could not set up IO Streams to xx-xx-xx-xx-xx.indata.com/xx.xx.xx.xx:16020 at org.apache.hadoop.hbase.ipc.RpcClientImpl$Connection.setupIOstreams(RpcClientImpl.java:777) at org.apache.hadoop.hbase.ipc.RpcClientImpl$Connection.writeRequest(RpcClientImpl.java:885) at org.apache.hadoop.hbase.ipc.RpcClientImpl$Connection.tracedWriteRequest(RpcClientImpl.java:854) at org.apache.hadoop.hbase.ipc.RpcClientImpl.call(RpcClientImpl.java:1180) at org.apache.hadoop.hbase.ipc.AbstractRpcClient.callBlockingMethod(AbstractRpcClient.java:213) at org.apache.hadoop.hbase.ipc.AbstractRpcClient$BlockingRpcChannelImplementation.callBlockingMethod(AbstractRpcClient.java:287) at org.apache.hadoop.hbase.protobuf.generated.ClientProtos$ClientService$BlockingStub.scan(ClientProtos.java:32651) at org.apache.hadoop.hbase.client.ScannerCallable.openScanner(ScannerCallable.java:372) at org.apache.hadoop.hbase.client.ScannerCallable.call(ScannerCallable.java:199) at org.apache.hadoop.hbase.client.ScannerCallable.call(ScannerCallable.java:62) at org.apache.hadoop.hbase.client.RpcRetryingCaller.callWithoutRetries(RpcRetryingCaller.java:200) at org.apache.hadoop.hbase.client.ScannerCallableWithReplicas$RetryingRPC.call(ScannerCallableWithReplicas.java:369) at org.apache.hadoop.hbase.client.ScannerCallableWithReplicas$RetryingRPC.call(ScannerCallableWithReplicas.java:343) at org.apache.hadoop.hbase.client.RpcRetryingCaller.callWithRetries(RpcRetryingCaller.java:126) ... 4 more Caused by: java.lang.RuntimeException: SASL authentication failed. The most likely cause is missing or invalid credentials. Consider 'kinit'. at org.apache.hadoop.hbase.ipc.RpcClientImpl$Connection$1.run(RpcClientImpl.java:677) at java.security.AccessController.doPrivileged(Native Method) at javax.security.auth.Subject.doAs(Subject.java:422) at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1628) at org.apache.hadoop.hbase.ipc.RpcClientImpl$Connection.handleSaslConnectionFailure(RpcClientImpl.java:635) at org.apache.hadoop.hbase.ipc.RpcClientImpl$Connection.setupIOstreams(RpcClientImpl.java:743) ... 17 more Caused by: javax.security.sasl.SaslException: GSS initiate failed [Caused by GSSException: No valid credentials provided (Mechanism level: Failed to find any Kerberos tgt)] at com.sun.security.sasl.gsskerb.GssKrb5Client.evaluateChallenge(GssKrb5Client.java:211) at org.apache.hadoop.hbase.security.HBaseSaslRpcClient.saslConnect(HBaseSaslRpcClient.java:179) at org.apache.hadoop.hbase.ipc.RpcClientImpl$Connection.setupSaslConnection(RpcClientImpl.java:609) at org.apache.hadoop.hbase.ipc.RpcClientImpl$Connection.access$600(RpcClientImpl.java:154) at org.apache.hadoop.hbase.ipc.RpcClientImpl$Connection$2.run(RpcClientImpl.java:735) at org.apache.hadoop.hbase.ipc.RpcClientImpl$Connection$2.run(RpcClientImpl.java:732) at java.security.AccessController.doPrivileged(Native Method) at javax.security.auth.Subject.doAs(Subject.java:422) at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1628) at org.apache.hadoop.hbase.ipc.RpcClientImpl$Connection.setupIOstreams(RpcClientImpl.java:732) ... 17 more Caused by: GSSException: No valid credentials provided (Mechanism level: Failed to find any Kerberos tgt) at sun.security.jgss.krb5.Krb5InitCredential.getInstance(Krb5InitCredential.java:147) at sun.security.jgss.krb5.Krb5MechFactory.getCredentialElement(Krb5MechFactory.java:122) at sun.security.jgss.krb5.Krb5MechFactory.getMechanismContext(Krb5MechFactory.java:187) at sun.security.jgss.GSSManagerImpl.getMechanismContext(GSSManagerImpl.java:224) at sun.security.jgss.GSSContextImpl.initSecContext(GSSContextImpl.java:212) at sun.security.jgss.GSSContextImpl.initSecContext(GSSContextImpl.java:179) at com.sun.security.sasl.gsskerb.GssKrb5Client.evaluateChallenge(GssKrb5Client.java:192) ... 26 more 求解原因,是因为票据过期吗?

java 远程连接hbase遇到问题,网上都是改本地host文件,有没有一种不需要改本地配置就可以连接到hbase然后可以用Admin的api方法,?

Configuration configuration = HBaseConfiguration.create(); configuration.set("hbase.rootdir", "hdfs://远程hbaseIP:9820/hbase"); configuration.set("hbase.zookeeper.quorum", "远程hbaseIP"); configuration.set("hbase.zookeeper.property.clientPort", "2181"); Connection conn = ConnectionFactory.createConnection(configuration); Admin admin = conn.getAdmin(); NamespaceDescriptor.Builder builder = NamespaceDescriptor.create("SpaceName"); 报错信息 WARN [org.apache.hadoop.util.Shell] - Did not find winutils.exe: java.io.FileNotFoundException: java.io.FileNotFoundException: HADOOP_HOME and hadoop.home.dir are unset. -see https://wiki.apache.org/hadoop/WindowsProblems WARN [org.apache.hadoop.util.NativeCodeLoader] - Unable to load native-hadoop library for your platform... using builtin-java classes where applicable Exception in thread "main" java.lang.NoSuchMethodError: org.apache.hadoop.security.HadoopKerberosName.setRuleMechanism(Ljava/lang/String;)V

通过javaAPI为hbase用户授权,实现acl接口

通过javaAPI为hbase中的用户进行授权,对表进行授权,实现hbase的acl接口的编写

IDEA连接HBase出现如下问题 请教一下。

代码如下 ** ``` //判断表是否存在 public static boolean tableExists(String tableName) throws IOException { //Hbase配置文件 HBaseConfiguration configuration = new HBaseConfiguration(); configuration.addResource("hbase-site.xml"); configuration.addResource("hdfs-site.xml"); configuration.addResource("core-site.xml"); configuration.set("hbase.zookeeper.quorum","192.168.159.102:2181"); //获取Hbase管理员对象 HBaseAdmin admin = new HBaseAdmin(configuration); // //执行 boolean tableExist = admin.tableExists(tableName); admin.close(); return tableExist; }** ``` ``` Exception in thread "main" java.io.IOException: java.lang.reflect.InvocationTargetException at org.apache.hadoop.hbase.client.ConnectionFactory.createConnection(ConnectionFactory.java:240) at org.apache.hadoop.hbase.client.ConnectionManager.createConnection(ConnectionManager.java:431) at org.apache.hadoop.hbase.client.ConnectionManager.createConnection(ConnectionManager.java:424) at org.apache.hadoop.hbase.client.ConnectionManager.getConnectionInternal(ConnectionManager.java:302) at org.apache.hadoop.hbase.client.HBaseAdmin.<init>(HBaseAdmin.java:238) at com.atgui.TestHbase.tableExists(TestHbase.java:19) at com.atgui.TestHbase.main(TestHbase.java:42) Caused by: java.lang.reflect.InvocationTargetException at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:490) at org.apache.hadoop.hbase.client.ConnectionFactory.createConnection(ConnectionFactory.java:238) ... 6 more Caused by: java.lang.UnsupportedOperationException: Constructor threw an exception for org.apache.hadoop.hbase.ipc.RpcClientImpl at org.apache.hadoop.hbase.util.ReflectionUtils.instantiate(ReflectionUtils.java:63) at org.apache.hadoop.hbase.util.ReflectionUtils.instantiateWithCustomCtor(ReflectionUtils.java:43) at org.apache.hadoop.hbase.ipc.RpcClientFactory.createClient(RpcClientFactory.java:75) at org.apache.hadoop.hbase.ipc.RpcClientFactory.createClient(RpcClientFactory.java:58) at org.apache.hadoop.hbase.client.ConnectionManager$HConnectionImplementation.<init>(ConnectionManager.java:693) ... 11 more Caused by: java.lang.reflect.InvocationTargetException at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:490) at org.apache.hadoop.hbase.util.ReflectionUtils.instantiate(ReflectionUtils.java:55) ... 15 more Caused by: java.lang.ExceptionInInitializerError at org.apache.hadoop.hbase.ipc.IPCUtil.<init>(IPCUtil.java:75) at org.apache.hadoop.hbase.ipc.AbstractRpcClient.<init>(AbstractRpcClient.java:101) at org.apache.hadoop.hbase.ipc.RpcClientImpl.<init>(RpcClientImpl.java:1125) at org.apache.hadoop.hbase.ipc.RpcClientImpl.<init>(RpcClientImpl.java:1153) ... 20 more Caused by: java.lang.RuntimeException: Unexpected version format: 11.0.1 at org.apache.hadoop.hbase.util.ClassSize.<clinit>(ClassSize.java:119) ... 24 more ```

java 如何访问远程 linux 服务器下利用docker容器建立的hbase集群

在远程linux服务器上利用docker搭建伪分布式集群的Hbase,如何在本地windows主机利用java来访问并进行操作。 ``` conf = HBaseConfiguration.create(); //我认为这里应该是我服务器的ip,因为容器的ip并没有映射到windows中 conf.set("hbase.zookeeper.quorum","192.168.10.168"); //2281是master容器zk2181端口的映射 conf.set("hbase.zookeeper.property.clientPort", "2281"); conn= ConnectionFactory.createConnection(conf); admin=conn.getAdmin(); System.out.println("connection success"); Table mk=conn.getTable(TableName.valueOf("user")); Get g = new Get(Bytes.toBytes("1234")); Result result = mk.get(g); ``` 如果这样子操作的话,运行到Result报缺少master主机的错误

java连hbase永久等待问题

只有一个有价值信息就是,Session establishment complete on server tb86-es01/172.18.1.86:2181, sessionid = 0x15b79d49b158594, negotiated timeout = 40000 代码如下: public class extract_hbase_job { private static Configuration hconf = null; static{ Configuration conf = new Configuration(); conf.set("hbase.zookeeper.quorum", "tb86-es01,tb87-es02,tb88-es03"); conf.set("hbase.zookeeper.property.clientPort", "2181"); System.setProperty("hadoop.home.dir", "D:\\work\\apache\\hadoop\\hadoop-2.6.0"); hconf = HBaseConfiguration.create(conf); } public static void getRecord(String tableName,String rowKey) throws Exception{ HTable table = new HTable(hconf, tableName.getBytes()); Get get = new Get(rowKey.getBytes()); Result rs = table.get(get); for (KeyValue kv : rs.raw()) { System.out.println(new String(kv.getQualifier()) + " " ); } @Test public void test() throws Exception{ extract_hbase_job.getRecord("default:relation_graph", "00:global:cp:10878983"); } } hbase中也有报错: java.lang.RuntimeException: Failed construction of Master: class org.apache.hadoop.hbase.master.HMaster at org.apache.hadoop.hbase.master.HMaster.constructMaster(HMaster.java:1867) at org.apache.hadoop.hbase.master.HMasterCommandLine.startMaster(HMasterCommandLine.java:198) at org.apache.hadoop.hbase.master.HMasterCommandLine.run(HMasterCommandLine.java:139) at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:70) at org.apache.hadoop.hbase.util.ServerCommandLine.doMain(ServerCommandLine.java:126) at org.apache.hadoop.hbase.master.HMaster.main(HMaster.java:1881) ed by: java.net.BindException: 地址已在使用 at sun.nio.ch.Net.bind0(Native Method) at sun.nio.ch.Net.bind(Net.java:444) at sun.nio.ch.Net.bind(Net.java:436) at sun.nio.ch.ServerSocketChannelImpl.bind(ServerSocketChannelImpl.java:214) at sun.nio.ch.ServerSocketAdaptor.bind(ServerSocketAdaptor.java:74) at org.apache.hadoop.hbase.ipc.RpcServer.bind(RpcServer.java:2366) at org.apache.hadoop.hbase.ipc.RpcServer$Listener.<init>(RpcServer.java:524) at org.apache.hadoop.hbase.ipc.RpcServer.<init>(RpcServer.java:1896) at org.apache.hadoop.hbase.regionserver.RSRpcServices.<init>(RSRpcServices.java:788) at org.apache.hadoop.hbase.master.MasterRpcServices.<init>(MasterRpcServices.java:197) at org.apache.hadoop.hbase.master.HMaster.createRpcServices(HMaster.java:401) at org.apache.hadoop.hbase.regionserver.HRegionServer.<init>(HRegionServer.java:487) at org.apache.hadoop.hbase.master.HMaster.<init>(HMaster.java:271) at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57) at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) at java.lang.reflect.Constructor.newInstance(Constructor.java:526) at org.apache.hadoop.hbase.master.HMaster.constructMaster(HMaster.java:1862) ... 5 more

java如何修改hbase表数据

注意:是修改hbase表的数据,不是新增、删除、查询,是修改

java调用Hbase java.net.SocketTimeoutException

hbase菜鸟,工作需要,请大神帮忙。java连接hbase出现的错误error如下: log4j:WARN No appenders could be found for logger (org.apache.hadoop.metrics2.lib.MutableMetricsFactory). log4j:WARN Please initialize the log4j system properly. log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info. org.apache.hadoop.hbase.client.RetriesExhaustedException: Failed after attempts=36, exceptions: Thu Apr 07 09:43:39 CST 2016, null, java.net.SocketTimeoutException: callTimeout=60000, callDuration=80156: row 'gpsinfo,,' on table 'hbase:meta' at region=hbase:meta,,1.1588230740, hostname=zpu-storage3,16020,1443175301611, seqNum=0 at org.apache.hadoop.hbase.client.RpcRetryingCallerWithReadReplicas.throwEnrichedException(RpcRetryingCallerWithReadReplicas.java:271) at org.apache.hadoop.hbase.client.ScannerCallableWithReplicas.call(ScannerCallableWithReplicas.java:207) at org.apache.hadoop.hbase.client.ScannerCallableWithReplicas.call(ScannerCallableWithReplicas.java:60) at org.apache.hadoop.hbase.client.RpcRetryingCaller.callWithoutRetries(RpcRetryingCaller.java:200) at org.apache.hadoop.hbase.client.ClientScanner.call(ClientScanner.java:320) at org.apache.hadoop.hbase.client.ClientScanner.loadCache(ClientScanner.java:401) at org.apache.hadoop.hbase.client.ClientScanner.next(ClientScanner.java:364) at org.apache.hadoop.hbase.MetaTableAccessor.fullScan(MetaTableAccessor.java:604) at org.apache.hadoop.hbase.MetaTableAccessor.tableExists(MetaTableAccessor.java:366) at org.apache.hadoop.hbase.client.HBaseAdmin.tableExists(HBaseAdmin.java:392) at org.apache.hadoop.hbase.client.HBaseAdmin.tableExists(HBaseAdmin.java:402) at Test.main(Test.java:19) Caused by: java.net.SocketTimeoutException: callTimeout=60000, callDuration=80156: row 'gpsinfo,,' on table 'hbase:meta' at region=hbase:meta,,1.1588230740, hostname=zpu-storage3,16020,1443175301611, seqNum=0 at org.apache.hadoop.hbase.client.RpcRetryingCaller.callWithRetries(RpcRetryingCaller.java:159) at org.apache.hadoop.hbase.client.ResultBoundedCompletionService$QueueingFuture.run(ResultBoundedCompletionService.java:65) at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) at java.lang.Thread.run(Unknown Source) Caused by: java.net.UnknownHostException: unknown host: zpu-storage3 at org.apache.hadoop.hbase.ipc.RpcClientImpl$Connection.<init>(RpcClientImpl.java:303) at org.apache.hadoop.hbase.ipc.RpcClientImpl.createConnection(RpcClientImpl.java:133) at org.apache.hadoop.hbase.ipc.RpcClientImpl.getConnection(RpcClientImpl.java:1283) at org.apache.hadoop.hbase.ipc.RpcClientImpl.call(RpcClientImpl.java:1191) at org.apache.hadoop.hbase.ipc.AbstractRpcClient.callBlockingMethod(AbstractRpcClient.java:222) at org.apache.hadoop.hbase.ipc.AbstractRpcClient$BlockingRpcChannelImplementation.callBlockingMethod(AbstractRpcClient.java:323) at org.apache.hadoop.hbase.protobuf.generated.ClientProtos$ClientService$BlockingStub.scan(ClientProtos.java:32831) at org.apache.hadoop.hbase.client.ScannerCallable.openScanner(ScannerCallable.java:373) at org.apache.hadoop.hbase.client.ScannerCallable.call(ScannerCallable.java:200) at org.apache.hadoop.hbase.client.ScannerCallable.call(ScannerCallable.java:62) at org.apache.hadoop.hbase.client.RpcRetryingCaller.callWithoutRetries(RpcRetryingCaller.java:200) at org.apache.hadoop.hbase.client.ScannerCallableWithReplicas$RetryingRPC.call(ScannerCallableWithReplicas.java:360) at org.apache.hadoop.hbase.client.ScannerCallableWithReplicas$RetryingRPC.call(ScannerCallableWithReplicas.java:334) at org.apache.hadoop.hbase.client.RpcRetryingCaller.callWithRetries(RpcRetryingCaller.java:126) ... 4 more

关于java开发hbase的框架

刚接触hbase,需要java客户端的编程。目前之了解到hbase客户端的API的编写。就是get,put之类的层次。但以往开发关系型数据库的时候都有很多框架。请问,有经验的朋友是如何快速开发基于hbase的程序的?谢谢?比如是用什么,可以使用sql语言来查询之类的。谢谢

连接hbase Connection refused: no further information

server环境: 在virtualbox里安装了ubuntu,然后装了了hadoop2.7.5,hbase1.3.1,然后hadoop和hbase的环境都配置好了 启动了hbase,然后本机里通过scala访问虚拟机里的hbase时,connection能获取到,但是在执行tableExists时,卡一会后就报超时了,client的代码和server的配置如: server配置(其中zookeeper用的hbase自己管理的): hbase-site.xml ![图片说明](https://img-ask.csdn.net/upload/201804/02/1522641879_341754.png) client的代码: ``` class HbaseUtil { def GetHbaseConfiguration(ip:String):Unit={ var conf = HBaseConfiguration.create; //这个是远程hbase的ip地址 conf.set("hbase.zookeeper.quorum",ip) //conf.set("zookeeper.znode.parent", "/hbase-unsecure") //2181是hbase里zookeeper的默认端口号 conf.set("hbase.zookeeper.property.clientPort","2181") println(ip+":habse connention success...") val tableName = "jndata" conf.set(TableInputFormat.INPUT_TABLE, tableName) val con= ConnectionFactory.createConnection(conf) val hBaseAdmin = con.getAdmin//new HBaseAdmin(conf); val tn = TableName.valueOf(tableName); // hBaseAdmin.disableTable(tn) // println(tableName + " is exist,detele....") //创建表 if (hBaseAdmin.tableExists(tn)) { println(tableName + " is exist,....") }else{ println(tableName + " is not exist,....") } } } ``` 然后server端的zookeeper的log如下: ![图片说明](https://img-ask.csdn.net/upload/201804/02/1522640993_389812.png) client端的异常如下: ``` Exception in thread "main" org.apache.hadoop.hbase.client.RetriesExhaustedException: Failed after attempts=36, exceptions: Mon Apr 02 11:30:11 CST 2018, null, java.net.SocketTimeoutException: callTimeout=60000, callDuration=76915: Connection refused: no further information row 'jndata,,' on table 'hbase:meta' at region=hbase:meta,,1.1588230740, hostname=simon-virtualbox,16201,1522631406769, seqNum=0 at org.apache.hadoop.hbase.client.RpcRetryingCallerWithReadReplicas.throwEnrichedException(RpcRetryingCallerWithReadReplicas.java:276) at org.apache.hadoop.hbase.client.ScannerCallableWithReplicas.call(ScannerCallableWithReplicas.java:210) at org.apache.hadoop.hbase.client.ScannerCallableWithReplicas.call(ScannerCallableWithReplicas.java:60) at org.apache.hadoop.hbase.client.RpcRetryingCaller.callWithoutRetries(RpcRetryingCaller.java:212) at org.apache.hadoop.hbase.client.ClientScanner.call(ClientScanner.java:314) at org.apache.hadoop.hbase.client.ClientScanner.nextScanner(ClientScanner.java:289) at org.apache.hadoop.hbase.client.ClientScanner.initializeScannerInConstruction(ClientScanner.java:164) at org.apache.hadoop.hbase.client.ClientScanner.<init>(ClientScanner.java:159) at org.apache.hadoop.hbase.client.HTable.getScanner(HTable.java:796) at org.apache.hadoop.hbase.MetaTableAccessor.fullScan(MetaTableAccessor.java:602) at org.apache.hadoop.hbase.MetaTableAccessor.tableExists(MetaTableAccessor.java:366) at org.apache.hadoop.hbase.client.HBaseAdmin.tableExists(HBaseAdmin.java:408) at rxb.flinkDemo.hbase.HbaseUtil.GetHbaseConfiguration(HbaseUtil.scala:42) at rxb.flinkDemo.MyDemo$.main(FlinkDemo.scala:27) at rxb.flinkDemo.MyDemo.main(FlinkDemo.scala) Caused by: java.net.SocketTimeoutException: callTimeout=60000, callDuration=76915: Connection refused: no further information row 'jndata,,' on table 'hbase:meta' at region=hbase:meta,,1.1588230740, hostname=simon-virtualbox,16201,1522631406769, seqNum=0 at org.apache.hadoop.hbase.client.RpcRetryingCaller.callWithRetries(RpcRetryingCaller.java:171) at org.apache.hadoop.hbase.client.ResultBoundedCompletionService$QueueingFuture.run(ResultBoundedCompletionService.java:65) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at java.lang.Thread.run(Thread.java:748) Caused by: java.net.ConnectException: Connection refused: no further information at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method) at sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:717) at org.apache.hadoop.net.SocketIOWithTimeout.connect(SocketIOWithTimeout.java:206) at org.apache.hadoop.net.NetUtils.connect(NetUtils.java:531) at org.apache.hadoop.net.NetUtils.connect(NetUtils.java:495) at org.apache.hadoop.hbase.ipc.RpcClientImpl$Connection.setupConnection(RpcClientImpl.java:416) at org.apache.hadoop.hbase.ipc.RpcClientImpl$Connection.setupIOstreams(RpcClientImpl.java:722) at org.apache.hadoop.hbase.ipc.RpcClientImpl$Connection.writeRequest(RpcClientImpl.java:909) at org.apache.hadoop.hbase.ipc.RpcClientImpl$Connection.tracedWriteRequest(RpcClientImpl.java:873) at org.apache.hadoop.hbase.ipc.RpcClientImpl.call(RpcClientImpl.java:1244) at org.apache.hadoop.hbase.ipc.AbstractRpcClient.callBlockingMethod(AbstractRpcClient.java:227) at org.apache.hadoop.hbase.ipc.AbstractRpcClient$BlockingRpcChannelImplementation.callBlockingMethod(AbstractRpcClient.java:336) at org.apache.hadoop.hbase.protobuf.generated.ClientProtos$ClientService$BlockingStub.scan(ClientProtos.java:35396) at org.apache.hadoop.hbase.client.ScannerCallable.openScanner(ScannerCallable.java:404) at org.apache.hadoop.hbase.client.ScannerCallable.call(ScannerCallable.java:211) at org.apache.hadoop.hbase.client.ScannerCallable.call(ScannerCallable.java:65) at org.apache.hadoop.hbase.client.RpcRetryingCaller.callWithoutRetries(RpcRetryingCaller.java:212) at org.apache.hadoop.hbase.client.ScannerCallableWithReplicas$RetryingRPC.call(ScannerCallableWithReplicas.java:364) at org.apache.hadoop.hbase.client.ScannerCallableWithReplicas$RetryingRPC.call(ScannerCallableWithReplicas.java:338) at org.apache.hadoop.hbase.client.RpcRetryingCaller.callWithRetries(RpcRetryingCaller.java:137) ... 4 more ``` 好多办法都试过了还是不行: 1.server和client的防火墙都关了 2.client的host里也配置了server的ip和hostname

HBASE如何创建用户名密码?

hbase如何创建用户名密码?java api如何指定用户名密码访问hbase

Java实现查询JanusGraph+hbase+ES

Java实现查询JanusGraph+hbase+ES springboot案例远程连接服务器的,本地连接已经调试通,需要一个远程连接的。

java通过solr查询hbase数据,如何自动映射到java实体类?

现在的情况是,使用simplehbase可以将查询结果自动映射到实体中,但simplehbase的过滤手段不如solr全面,能否将simplehbase与solr结合起来使用?如果可以,该怎么做呢?如果不可以,有没有办法可以达到以下目的? 目的: 1)可以模糊查询 2)查询出的结果自动映射到java实体类中

tomcat启动情况下连接hbase失败!!!

如图,单元测试代码无误。启动tomcat后调用方法出现问题,创建与hbase的连接失败,求大神赐教![图片说明](http://forum.csdn.net/PointForum/ui/scripts/csdn/Plugin/001/face/18.gif)![图片说明](http://forum.csdn.net/PointForum/ui/scripts/csdn/Plugin/001/face/18.gif)![图片](https://img-ask.csdn.net/upload/201607/13/1468419918_757967.jpg)![图片](https://img-ask.csdn.net/upload/201607/13/1468420024_773845.jpg)![图片](https://img-ask.csdn.net/upload/201607/13/1468420029_629464.jpg)

如何用java操作hbase实现对行键的模糊查询

//这个代码该怎么改成行键的模糊查询呢 List<UFile> list=new ArrayList<UFile>(); Table table=conn.getTable(TableName.valueOf("yunpro")); Get get = new Get(Bytes.toBytes("lrd")); get.addColumn(Bytes.toBytes("picture"), Bytes.toBytes("alert")) Scan scan=new Scan(get); Result res = table.get(get);

大学四年自学走来,这些私藏的实用工具/学习网站我贡献出来了

大学四年,看课本是不可能一直看课本的了,对于学习,特别是自学,善于搜索网上的一些资源来辅助,还是非常有必要的,下面我就把这几年私藏的各种资源,网站贡献出来给你们。主要有:电子书搜索、实用工具、在线视频学习网站、非视频学习网站、软件下载、面试/求职必备网站。 注意:文中提到的所有资源,文末我都给你整理好了,你们只管拿去,如果觉得不错,转发、分享就是最大的支持了。 一、电子书搜索 对于大部分程序员...

在中国程序员是青春饭吗?

今年,我也32了 ,为了不给大家误导,咨询了猎头、圈内好友,以及年过35岁的几位老程序员……舍了老脸去揭人家伤疤……希望能给大家以帮助,记得帮我点赞哦。 目录: 你以为的人生 一次又一次的伤害 猎头界的真相 如何应对互联网行业的「中年危机」 一、你以为的人生 刚入行时,拿着傲人的工资,想着好好干,以为我们的人生是这样的: 等真到了那一天,你会发现,你的人生很可能是这样的: ...

Java基础知识面试题(2020最新版)

文章目录Java概述何为编程什么是Javajdk1.5之后的三大版本JVM、JRE和JDK的关系什么是跨平台性?原理是什么Java语言有哪些特点什么是字节码?采用字节码的最大好处是什么什么是Java程序的主类?应用程序和小程序的主类有何不同?Java应用程序与小程序之间有那些差别?Java和C++的区别Oracle JDK 和 OpenJDK 的对比基础语法数据类型Java有哪些数据类型switc...

我以为我学懂了数据结构,直到看了这个导图才发现,我错了

数据结构与算法思维导图

String s = new String(" a ") 到底产生几个对象?

老生常谈的一个梗,到2020了还在争论,你们一天天的,哎哎哎,我不是针对你一个,我是说在座的各位都是人才! 上图红色的这3个箭头,对于通过new产生一个字符串(”宜春”)时,会先去常量池中查找是否已经有了”宜春”对象,如果没有则在常量池中创建一个此字符串对象,然后堆中再创建一个常量池中此”宜春”对象的拷贝对象。 也就是说准确答案是产生了一个或两个对象,如果常量池中原来没有 ”宜春” ,就是两个。...

技术大佬:我去,你写的 switch 语句也太老土了吧

昨天早上通过远程的方式 review 了两名新来同事的代码,大部分代码都写得很漂亮,严谨的同时注释也很到位,这令我非常满意。但当我看到他们当中有一个人写的 switch 语句时,还是忍不住破口大骂:“我擦,小王,你丫写的 switch 语句也太老土了吧!” 来看看小王写的代码吧,看完不要骂我装逼啊。 private static String createPlayer(PlayerTypes p...

Linux面试题(2020最新版)

文章目录Linux 概述什么是LinuxUnix和Linux有什么区别?什么是 Linux 内核?Linux的基本组件是什么?Linux 的体系结构BASH和DOS之间的基本区别是什么?Linux 开机启动过程?Linux系统缺省的运行级别?Linux 使用的进程间通信方式?Linux 有哪些系统日志文件?Linux系统安装多个桌面环境有帮助吗?什么是交换空间?什么是root帐户什么是LILO?什...

Linux命令学习神器!命令看不懂直接给你解释!

大家都知道,Linux 系统有非常多的命令,而且每个命令又有非常多的用法,想要全部记住所有命令的所有用法,恐怕是一件不可能完成的任务。 一般情况下,我们学习一个命令时,要么直接百度去搜索它的用法,要么就直接用 man 命令去查看守冗长的帮助手册。这两个都可以实现我们的目标,但有没有更简便的方式呢? 答案是必须有的!今天给大家推荐一款有趣而实用学习神器 — kmdr,让你解锁 Linux 学习新姿势...

和黑客斗争的 6 天!

互联网公司工作,很难避免不和黑客们打交道,我呆过的两家互联网公司,几乎每月每天每分钟都有黑客在公司网站上扫描。有的是寻找 Sql 注入的缺口,有的是寻找线上服务器可能存在的漏洞,大部分都...

史上最全的 python 基础知识汇总篇,没有比这再全面的了,建议收藏

网友们有福了,小编终于把基础篇的内容全部涉略了一遍,这是一篇关于基础知识的汇总的文章,请朋友们收下,不用客气,不过文章篇幅肯能会有点长,耐心阅读吧爬虫(七十)多进程multiproces...

讲一个程序员如何副业月赚三万的真实故事

loonggg读完需要3分钟速读仅需 1 分钟大家好,我是你们的校长。我之前讲过,这年头,只要肯动脑,肯行动,程序员凭借自己的技术,赚钱的方式还是有很多种的。仅仅靠在公司出卖自己的劳动时...

女程序员,为什么比男程序员少???

昨天看到一档综艺节目,讨论了两个话题:(1)中国学生的数学成绩,平均下来看,会比国外好?为什么?(2)男生的数学成绩,平均下来看,会比女生好?为什么?同时,我又联想到了一个技术圈经常讨...

85后蒋凡:28岁实现财务自由、34岁成为阿里万亿电商帝国双掌门,他的人生底层逻辑是什么?...

蒋凡是何许人也? 2017年12月27日,在入职4年时间里,蒋凡开挂般坐上了淘宝总裁位置。 为此,时任阿里CEO张勇在任命书中力赞: 蒋凡加入阿里,始终保持创业者的冲劲,有敏锐的...

总结了 150 余个神奇网站,你不来瞅瞅吗?

原博客再更新,可能就没了,之后将持续更新本篇博客。

副业收入是我做程序媛的3倍,工作外的B面人生是怎样的?

提到“程序员”,多数人脑海里首先想到的大约是:为人木讷、薪水超高、工作枯燥…… 然而,当离开工作岗位,撕去层层标签,脱下“程序员”这身外套,有的人生动又有趣,马上展现出了完全不同的A/B面人生! 不论是简单的爱好,还是正经的副业,他们都干得同样出色。偶尔,还能和程序员的特质结合,产生奇妙的“化学反应”。 @Charlotte:平日素颜示人,周末美妆博主 大家都以为程序媛也个个不修边幅,但我们也许...

MySQL数据库面试题(2020最新版)

文章目录数据库基础知识为什么要使用数据库什么是SQL?什么是MySQL?数据库三大范式是什么mysql有关权限的表都有哪几个MySQL的binlog有有几种录入格式?分别有什么区别?数据类型mysql有哪些数据类型引擎MySQL存储引擎MyISAM与InnoDB区别MyISAM索引与InnoDB索引的区别?InnoDB引擎的4大特性存储引擎选择索引什么是索引?索引有哪些优缺点?索引使用场景(重点)...

新一代神器STM32CubeMonitor介绍、下载、安装和使用教程

关注、星标公众号,不错过精彩内容作者:黄工公众号:strongerHuang最近ST官网悄悄新上线了一款比较强大的工具:STM32CubeMonitor V1.0.0。经过我研究和使用之...

如果你是老板,你会不会踢了这样的员工?

有个好朋友ZS,是技术总监,昨天问我:“有一个老下属,跟了我很多年,做事勤勤恳恳,主动性也很好。但随着公司的发展,他的进步速度,跟不上团队的步伐了,有点...

我入职阿里后,才知道原来简历这么写

私下里,有不少读者问我:“二哥,如何才能写出一份专业的技术简历呢?我总感觉自己写的简历太烂了,所以投了无数份,都石沉大海了。”说实话,我自己好多年没有写过简历了,但我认识的一个同行,他在阿里,给我说了一些他当年写简历的方法论,我感觉太牛逼了,实在是忍不住,就分享了出来,希望能够帮助到你。 01、简历的本质 作为简历的撰写者,你必须要搞清楚一点,简历的本质是什么,它就是为了来销售你的价值主张的。往深...

大学一路走来,学习互联网全靠这几个网站,最终拿下了一把offer

大佬原来都是这样炼成的

离职半年了,老东家又发 offer,回不回?

有小伙伴问松哥这个问题,他在上海某公司,在离职了几个月后,前公司的领导联系到他,希望他能够返聘回去,他很纠结要不要回去? 俗话说好马不吃回头草,但是这个小伙伴既然感到纠结了,我觉得至少说明了两个问题:1.曾经的公司还不错;2.现在的日子也不是很如意。否则应该就不会纠结了。 老实说,松哥之前也有过类似的经历,今天就来和小伙伴们聊聊回头草到底吃不吃。 首先一个基本观点,就是离职了也没必要和老东家弄的苦...

为什么你不想学习?只想玩?人是如何一步一步废掉的

不知道是不是只有我这样子,还是你们也有过类似的经历。 上学的时候总有很多光辉历史,学年名列前茅,或者单科目大佬,但是虽然慢慢地长大了,你开始懈怠了,开始废掉了。。。 什么?你说不知道具体的情况是怎么样的? 我来告诉你: 你常常潜意识里或者心理觉得,自己真正的生活或者奋斗还没有开始。总是幻想着自己还拥有大把时间,还有无限的可能,自己还能逆风翻盘,只不是自己还没开始罢了,自己以后肯定会变得特别厉害...

什么时候跳槽,为什么离职,你想好了么?

都是出来打工的,多为自己着想

为什么程序员做外包会被瞧不起?

二哥,有个事想询问下您的意见,您觉得应届生值得去外包吗?公司虽然挺大的,中xx,但待遇感觉挺低,马上要报到,挺纠结的。

当HR压你价,说你只值7K,你该怎么回答?

当HR压你价,说你只值7K时,你可以流畅地回答,记住,是流畅,不能犹豫。 礼貌地说:“7K是吗?了解了。嗯~其实我对贵司的面试官印象很好。只不过,现在我的手头上已经有一份11K的offer。来面试,主要也是自己对贵司挺有兴趣的,所以过来看看……”(未完) 这段话主要是陪HR互诈的同时,从公司兴趣,公司职员印象上,都给予对方正面的肯定,既能提升HR的好感度,又能让谈判气氛融洽,为后面的发挥留足空间。...

面试阿里p7,被按在地上摩擦,鬼知道我经历了什么?

面试阿里p7被问到的问题(当时我只知道第一个):@Conditional是做什么的?@Conditional多个条件是什么逻辑关系?条件判断在什么时候执...

你期望月薪4万,出门右拐,不送,这几个点,你也就是个初级的水平

先来看几个问题通过注解的方式注入依赖对象,介绍一下你知道的几种方式@Autowired和@Resource有何区别说一下@Autowired查找候选者的...

面试了一个 31 岁程序员,让我有所触动,30岁以上的程序员该何去何从?

最近面试了一个31岁8年经验的程序猿,让我有点感慨,大龄程序猿该何去何从。

大三实习生,字节跳动面经分享,已拿Offer

说实话,自己的算法,我一个不会,太难了吧

程序员垃圾简历长什么样?

已经连续五年参加大厂校招、社招的技术面试工作,简历看的不下于万份 这篇文章会用实例告诉你,什么是差的程序员简历! 疫情快要结束了,各个公司也都开始春招了,作为即将红遍大江南北的新晋UP主,那当然要为小伙伴们做点事(手动狗头)。 就在公众号里公开征简历,义务帮大家看,并一一点评。《启舰:春招在即,义务帮大家看看简历吧》 一石激起千层浪,三天收到两百多封简历。 花光了两个星期的所有空闲时...

立即提问
相关内容推荐