小编fxm*_*fxm的帖子

使用Hadoop或HBase或Hive有什么好处？

根据我的理解,HBase避免使用map-reduce,并且在HDFS之上具有面向列的存储.Hive是Hadoop和HBase的类似sql的接口.

我也想知道Hive与Pig的比较.

我们有一个提取对象异步的动作,让我们调用它getPostDetails,它接受一个由id获取的帖子的参数.向用户显示帖子列表,可以单击其中一个以获取一些详细信息.

如果用户点击"发布#1",我们会发送一个GET_POST可能看起来像这样的动作.

const getPostDetails = (id) => ({
  type: c.GET_POST_DETAILS,
  promise: (http) => http.get(`http://example.com/posts/#${id}`),
  returnKey: 'facebookData'
})

这是由中间件选择的,它为promise添加了一个成功处理程序,它将调用GET_POST__OK与反序列化的JSON对象类似的操作 .reducer看到这个对象并将其应用于商店.典型的 __OK减速机看起来像这样.

[c.GET_ALL__OK]: (state, response) => assign(state, {
  currentPost: response.postDetails
})

后来我们有了一个组件,可以查看currentPost并显示当前帖子的详细信息.

但是,我们有竞争条件.如果用户一个接一个地提交两个GET_POST_DETAILS动作,则无法保证我们接收__OK动作的顺序,如果第二个http请求在第一个http请求之前完成,则状态将变为不正确.

    Action                   => Result
    ---------------------------------------------------------------------------------
|T| User Clicks Post #1      => GET_POST for #1 dispatched => Http Request #1 pending
|i| User Clicks Post #2      => GET_POST for #2 dispatched => Http Request #2 pending
|m| Http …

尽管进行了一些搜索,但我还是找不到使用QT Creator 2.3.1自动生成C++类的getter和setter的方法.你们知道某种方法吗？

问题非常简单.我正在尝试使用以下命令在Windows上编译Hadoop2.4.1:

mvn clean package -Pdist,native-win -DskipTests -Dtar

有了JAVA_HOME=C:\Program Files\Java\jdk1.7.0_51,它工作正常.

有JAVA_HOME=C:\Program Files\Java\jdk1.8.0_05,它没有,并且没有给我以下错误:

[INFO] Apache Hadoop Annotations ......................... FAILURE [4.086s]
---
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-javadoc-plugin:2.8
.1:jar (module-javadocs) on project hadoop-annotations: MavenReportException: Er
ror while creating archive:
[ERROR] Exit code: 1 - C:\hadoop-src\hadoop-common-project\hadoop-annotations\sr
c\main\java\org\apache\hadoop\classification\InterfaceStability.java:27: error:
unexpected end tag: </ul>
[ERROR] * </ul>
[ERROR] ^
[ERROR]
[ERROR] Command line was: "C:\Program Files\Java\jdk1.8.0_05\jre\..\bin\javadoc.
exe" -J-Dhttp.proxySet=true -J-Dhttp.proxyHost=proxy -J-Dhttp.proxyPort=3128 @op
tions @packages
[ERROR]
[ERROR] Refer to the generated Javadoc files in …

是否存在现有的C++ NLP API？我发现的最接近的是CLucene,一个端口Lucene.但是,它似乎有点过时,文档远未完成.

理想情况下,这个/这些API将允许标记化,词干化和PoS标记.

我安装了Hadoop2.2.0和Hbase0.98.0,这就是我的工作:

$ ./bin/start-hbase.sh 

$ ./bin/hbase shell

2.0.0-p353 :001 > list

然后我得到了这个:

ERROR: Can't get master address from ZooKeeper; znode data == null

为什么我收到此错误？另一个问题:我需要运行./sbin/start-dfs.sh和./sbin/start-yarn.sh之前我跑基地？

还有什么用于./sbin/start-dfs.sh和./sbin/start-yarn.sh？

以下是我的一些conf doc:

HBase的-sites.xml

<configuration>
    <property>
        <name>hbase.rootdir</name>
        <value>hdfs://127.0.0.1:9000/hbase</value>
    </property>
    <property>
        <name>hbase.cluster.distributed</name>
        <value>true</value>
    </property>

    <property>
        <name>hbase.tmp.dir</name>
        <value>/Users/apple/Documents/tools/hbase-tmpdir/hbase-data</value>
    </property>
    <property>
        <name>hbase.zookeeper.quorum</name>
        <value>localhost</value>
    </property>
    <property>
        <name>hbase.zookeeper.property.dataDir</name>
        <value>/Users/apple/Documents/tools/hbase-zookeeper/zookeeper</value>
    </property>
</configuration>

核心sites.xml

<configuration>

  <property>
      <name>fs.defaultFS</name>
      <value>hdfs://localhost:9000</value>
      <description>The name of the default file system.</description>
  </property>

  <property>
      <name>hadoop.tmp.dir</name>
      <value>/Users/micmiu/tmp/hadoop</value>
      <description>A base for other temporary directories.</description>
  </property> …

我正在使用ubuntu 12.02 32bit并成功安装了hadoop2.2.0和pig 0.12.Hadoop在我的系统上正常运行.

但是,每当我运行此命令时:

data = load 'atoz.csv' using PigStorage(',')  as (aa1:int, bb1:int, cc1:int, dd1:chararray);            
dump data;

我收到以下错误:

ERROR org.apache.hadoop.mapreduce.lib.jobcontrol.JobControl - Error whiletrying to run jobs.java.lang.IncompatibleClassChangeError: Found interface org.apache.hadoop.mapreduce.JobContext, but class was expected.

这是完整的堆栈跟踪:

> 2014-01-23 10:41:44,998 [main] INFO  org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.MapReduceLauncher- 1 map-reduce job(s) waiting for submission.
>             2014-01-23 10:41:45,000 [Thread-9] INFO  org.apache.hadoop.metrics.jvm.JvmMetrics - Cannot initialize JVM
> Metrics with processName=JobTracker, sessionId= - already initialized
>             2014-01-23 10:41:45,001 [Thread-9] ERROR org.apache.hadoop.mapreduce.lib.jobcontrol.JobControl - Error while
> trying …

我正试图通过Yarn在我的Hadoop集群上运行spark shell.我用

• Hadoop 2.4.1
• Spark 1.0.0

我的Hadoop集群已经运行了.为了使用Spark,我按照这里描述的方式构建了Spark :

mvn -Pyarn -Phadoop-2.4 -Dhadoop.version=2.4.1 -DskipTests clean package

编译工作正常,我可以spark-shell毫无困难地运行.但是,在纱线上运行它:

spark-shell --master yarn-client

我遇到以下错误:

14/07/07 11:30:32 INFO cluster.YarnClientSchedulerBackend: Application report from ASM:
         appMasterRpcPort: -1
         appStartTime: 1404725422955
         yarnAppState: ACCEPTED

14/07/07 11:30:33 INFO cluster.YarnClientSchedulerBackend: Application report from ASM:
         appMasterRpcPort: -1
         appStartTime: 1404725422955
         yarnAppState: FAILED

org.apache.spark.SparkException: Yarn application already ended,might be killed or not able to launch application master
.
        at org.apache.spark.scheduler.cluster.YarnClientSchedulerBackend.waitForApp(YarnClientSchedulerBackend.scala:105
)
        at org.apache.spark.scheduler.cluster.YarnClientSchedulerBackend.start(YarnClientSchedulerBackend.scala:82)
        at org.apache.spark.scheduler.TaskSchedulerImpl.start(TaskSchedulerImpl.scala:136)
        at org.apache.spark.SparkContext.<init>(SparkContext.scala:318)
        at org.apache.spark.repl.SparkILoop.createSparkContext(SparkILoop.scala:957)
        at $iwC$$iwC.<init>(<console>:8) …

我打开记事本(Windows)并写

Some lines with special characters
Special: Ž?š??

并转到另存为... "someFile.txt",其中Encoding设置为UTF-8.

在Java中我有

FileInputStream fis = new FileInputStream(new File("someFile.txt"));
InputStreamReader isr = new InputStreamReader(fis, "UTF-8");
BufferedReader in = new BufferedReader(isr);

String line;
while((line = in.readLine()) != null) {                         
    printLine(line);
}
in.close();

但我得到问号和类似的"特殊"字符.为什么？

编辑:我有这个输入(.txt文件中的一行)

665,Ž?š??

和这段代码

FileInputStream fis = new FileInputStream(new File(fileName));
InputStreamReader isr = new InputStreamReader(fis, "UTF-8");
BufferedReader in = new BufferedReader(isr);

String line;
while((line = in.readLine()) != null) {
    Toast.makeText(mContext, line, Toast.LENGTH_LONG).show();

    Pattern …

我正在尝试通过谷歌教程建立良好的ap架构.我正在使用java 8和SDK 26.这是我到目前为止的代码:

package test.me;

import android.app.Fragment;
import android.arch.lifecycle.ViewModel;
import android.arch.lifecycle.ViewModelProviders;
import android.os.Bundle;
import android.support.annotation.Nullable;

public class ChronoFragment extends Fragment {

    private ViewModel my_model;

    @Override
    public void onActivityCreated(@Nullable Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
        my_model = ViewModelProviders.of(this).get(ViewModel.class);  // <-- error on this
        // and so on
    }
}

问题是到目前为止,SDK返回以下错误:

Cannot resolve the method 'of(test.me.ChronoFragment)'.

我从此不明白这一点

• ChronoFragment 是Fragment类型
• 方法ViewModelProviders#of(Fragment)确实存在,可以通过sdk访问.

关于我做错了什么的任何想法？