2023年9月13日每日随笔

 今天上了软件构造，对于java的概念有加深了解了一些，对于打包生成exe文件有了了解，对于软件设计，进行了创建型模式的学习，同时对于zookeeper帮别人配置了好几遍，对于hbase，学习了idea进行连接集群，创建表，进行操作，也进行idea的连接配置：

新建连接

 

导入maven配置

<dependencies>
        <dependency>
            <groupId>org.apache.hbase</groupId>
            <artifactId>hbase-client</artifactId>
            <version>2.4.11</version>
            <exclusions>
                <exclusion>
                    <groupId>org.glassfish</groupId>
                    <artifactId>javax.el</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupId>org.glassfish</groupId>
            <artifactId>javax.el</artifactId>
            <version>3.0.1-b06</version>
        </dependency>
</dependencies>

创建HbaseConnection

编写

 public static void main(String[] args) throws IOException {
        //1、创建连接配置对象
        Configuration configuration = new Configuration();

        //2、添加配置参数
        configuration.set("hbase.zookeeper.quorum","hadoop102,hadoop103,hadoop104");

        //3、创建连接（默认同步连接）
        Connection connection = ConnectionFactory.createConnection(configuration);

        //异步连接
        // CompletableFuture<AsyncConnection> asyncConnection = ConnectionFactory.createAsyncConnection(configuration);

        //4、使用连接
        System.out.println(connection);

        //关闭连接
        connection.close();
    }

多线程进行连接：(推荐）

本地配置文件

<?xml version="1.0"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>
<!--
/*
 * 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.
 */
-->
<configuration>
    <!--
      The following properties are set for running HBase as a single process on a
      developer workstation. With this configuration, HBase is running in
      "stand-alone" mode and without a distributed file system. In this mode, and
      without further configuration, HBase and ZooKeeper data are stored on the
      local filesystem, in a path under the value configured for `hbase.tmp.dir`.
      This value is overridden from its default value of `/tmp` because many
      systems clean `/tmp` on a regular basis. Instead, it points to a path within
      this HBase installation directory.

      Running against the `LocalFileSystem`, as opposed to a distributed
      filesystem, runs the risk of data integrity issues and data loss. Normally
      HBase will refuse to run in such an environment. Setting
      `hbase.unsafe.stream.capability.enforce` to `false` overrides this behavior,
      permitting operation. This configuration is for the developer workstation
      only and __should not be used in production!__

      See also https://hbase.apache.org/book.html#standalone_dist
    -->

    <property>
        <name>hbase.zookeeper.quorum</name>
        <value>hadoop102,hadoop103,hadoop104</value>
        <description>The directory shared by RegionServers.
        </description>
    </property>

</configuration>

public static Connection connection = null;
    static {
        //1、创建连接(同步连接）
        try {
            //读取本地文件形式添加参数
            connection = ConnectionFactory.createConnection();
        } catch (IOException e) {
            throw new RuntimeException(e);
        }

    }
    public static void closeConnection() throws IOException {
        //判断连接是否为空
        if(connection != null)
        {
            connection.close();
        }
    }

    public static void main(String[] args) throws IOException {
        /*
        //1、创建连接配置对象
        Configuration configuration = new Configuration();

        //2、添加配置参数
        configuration.set("hbase.zookeeper.quorum","hadoop102,hadoop103,hadoop104");

        //3、创建连接（默认同步连接）
        Connection connection = ConnectionFactory.createConnection(configuration);

        //异步连接
        // CompletableFuture<AsyncConnection> asyncConnection = ConnectionFactory.createAsyncConnection(configuration);

        //4、使用连接
        System.out.println(connection);

        //关闭连接
        connection.close();
        */
//        直接使用创建好的连接，不在main线程里单独创建
        System.out.println(HbaseConnection.connection);

        //在main线程里进行关闭连接
        HbaseConnection.closeConnection();
    }

 

 

用idea进行DDL

 

创建HbaseDDL.class

import org.apache.hadoop.hbase.NamespaceDescriptor;
import org.apache.hadoop.hbase.TableName;
import org.apache.hadoop.hbase.client.*;
import org.apache.hadoop.hbase.util.Bytes;

import java.io.IOException;

public class HbaseDDL {
    //声明一个静态属性获取到连接
    public static Connection connection = HbaseConnection.connection;


    /**
     * 创建命名空间
     * @param namespace 命名空间名称
     */
    public static void createNamespace(String namespace) throws IOException {
        //1、获取admin
        // 此处异常先不抛出，等待方法写完，在进行统一处理
        // admin连接轻量级的，不是线程安全的，不推荐池化或者缓存这个连接
        Admin admin = connection.getAdmin();

        //2、调用方法创建命名空间
        //代码相对shell更加底层，所以shell可以实现的，代码一定可以实现

        //2.1创建命名空间描述建造者 =>设计师
        NamespaceDescriptor.Builder builder = NamespaceDescriptor.create(namespace);

        //2.2 给命名空间添加需求
        builder.addConfiguration("user","atguigu");

        //2.3使用builder构造出对应完整的对象，完成创建
        //创建命名空间的问题，都属于本方法的问题，不应该抛出
        try {
            admin.createNamespace(builder.build());
        } catch (IOException e) {
            e.printStackTrace();
        }

        //3、关闭创建
        admin.close();

    }

    /**
     * 判断表格是否存在
     * @param namespace 命名空间名称
     * @param tableName 表格名称
     * @return true 表示存在
     */
    public static boolean isTableExists(String namespace,String tableName) throws IOException {
        // 1、获取admin
        Admin admin = connection.getAdmin();

        //2、使用方法判断表格是否存在
        boolean b = false;
        try {
            b = admin.tableExists(TableName.valueOf(namespace, tableName));
        } catch (IOException e) {
           e.printStackTrace();
        }

        //3、关闭连接
        admin.close();

        //返回结果
        return b;
    }

    /**
     * 创建表格
     * @param namespace 命名空间名称
     * @param tableName 表格名称
     * @param columnFamilies 列族名称 可以有多个
     */
    public static void createTable(String namespace,String tableName,String... columnFamilies) throws IOException {
        //1、获取admin
        Admin admin = connection.getAdmin();

        //2、调用方法创建表格
        //2.1 创建表格描述的建造者
        TableDescriptorBuilder tableDescriptorBuilder = TableDescriptorBuilder.newBuilder(TableName.valueOf(namespace, tableName));

        //2.2 添加参数
        for (String columnFamily : columnFamilies) {
        //2.3 创建列族描述
            ColumnFamilyDescriptorBuilder columnFamilyDescriptorBuilder =
                    ColumnFamilyDescriptorBuilder.newBuilder(Bytes.toBytes(columnFamily));

        //2.4 对应当前的列族添加参数
        //添加版本参数
            columnFamilyDescriptorBuilder.setMaxVersions(5);
            //2.5 创建添加完参数的列族描述
            tableDescriptorBuilder.setColumnFamily(columnFamilyDescriptorBuilder.build());
        }

        // 创建对应表格描述
        try {
            admin.createTable(tableDescriptorBuilder.build());
        } catch (IOException e) {
            e.printStackTrace();
        }

        //关闭admin
        admin.close();

    }

    public static void main(String[] args) throws IOException {
        //测试创建命名空间
        //应该先保证连接没有问题，再来调用相关方法
//        createNamespace("atguigu");

        //测试判断表格是否存在
        System.out.println(isTableExists("bigdata", "student"));

        //测试创建表格
        createTable("atguigu","student","info","msg");
        //其他代码
        System.out.println("其他代码");

        //关闭Hbase连接
        HbaseConnection.closeConnection();
    }
}