28-hadoop-hbase入门小程序

Posted 2020-10-04 bronk

hbase的完全分布式建立起来了, 可以试下好使不

1, 导包, {HBASE_HOME}/lib 下所有的jar包, 导入

2, 使用junit测试, 会报错, 因为缺少一个jar

3, 获取链接, 只需要提供zookeeper的地址即可

    /**
     * 获取链接, 只需要zookeeper的链接就可了
     */
    @Before
    public void beforeTest() throws IOException {
        Configuration conf = HBaseConfiguration.create();
        // hbase端口默认2181, 可以使用hbase.zookeeper.property.clientPort设置
        conf.set("hbase.zookeeper.quorum", "192.168.208.106,192.168.208.107,192.168.208.108");
        // 去的数据库连接对象
        connect = ConnectionFactory.createConnection(conf);
    }

    /**
     * 关闭资源
     */
    @After
    public void afterTest() throws IOException {
        if (connect != null) {
            connect.close();
        }
    }

 

4, 新建表

    @Test
    public void testCreate() throws IOException {
        //去的一个数据库元操作对象
        Admin admin = connect.getAdmin();
        if (admin.tableExists(table)) {
            // 删除需要先disable
            admin.disableTable(table);
            admin.deleteTable(table);
        }
        // 创建表描述对象
        HTableDescriptor htable = new HTableDescriptor(table);

        // 创建列族描述对象
        HColumnDescriptor hColumn = new HColumnDescriptor("cf1".getBytes());
        hColumn.setMaxVersions(5);
        hColumn.setBlockCacheEnabled(true);
        hColumn.setBlocksize(1800000);

        // 数据库中新建一个列族
        htable.addFamily(hColumn);
        // 新建数据库
        admin.createTable(htable);
    }

5, 插入模拟数据 

    /**
     * 数据插入
     */
    @Test
    public void testInsert() throws IOException {
        Table table = connect.getTable(tableName);

        List<Put> list = new ArrayList<>();

        for (int i = 0; i < 1000; i++) {
            int month = i % 3;
            int day = i % 9;
            Put put = new Put(getRowKey("138", month, day).getBytes());
            // 列1
            put.addColumn("cf1".getBytes(), "address".getBytes(), "bj".getBytes());
            // 列2
            put.addColumn("cf1".getBytes(), "type".getBytes(), String.valueOf(random.nextInt(2)).getBytes());
            list.add(put);
        }
        table.put(list);
　　　　 table.flushCommits();
    }

生成模拟rowkey的方法为: 

    /**
     * rowkey 生成策略, 电话号 + 日期
     */
    public String getRowKey(String prePhone, int month, int day) {
        return prePhone + random.nextInt(99999999) + "_2017" + month + day;
    }

6, 根据rowkey进行查询

因为, rowkey 默认按照字典进行排序

    /**
     * 根据rowkey 查询
     * @throws IOException
     */
    @Test
    public void scan() throws IOException {
        Table table = connect.getTable(tableName);
        //rowkey 按照字典排序, 所以可以截取
        Scan scan = new Scan("13862288854_201700".getBytes(), "13899338829_201714".getBytes());
        ResultScanner scanner = table.getScanner(scan);

        for (Iterator<Result> iterator = scanner.iterator(); iterator.hasNext(); ) {
            Result next = iterator.next();
            byte[] value = next.getValue("cf1".getBytes(), "type".getBytes());
            System.out.println(new String(value, "utf8"));
        }
    }

7, filter条件过滤

更多可见: http://hbase.apache.org/book.html#client.filter 第67条, 82.8 条 

更多filter, 找了个比较详细的博客: http://blog.csdn.net/cnweike/article/details/42920547

    @Test
    public void filter() throws IOException {
        // All表示全部匹配, 相当于and, one 相当于 or
        FilterList filterList = new FilterList(FilterList.Operator.MUST_PASS_ALL);

        // 查询某一个电话, type 等于 1
        PrefixFilter prefixFilter = new PrefixFilter("1388".getBytes());
        SingleColumnValueFilter singleColumnValueFilter = new SingleColumnValueFilter("cf1".getBytes(), "type".getBytes(), CompareFilter.CompareOp.EQUAL, "1".getBytes());
        // 过滤器是对结果排序, 所以顺序影响效率
        filterList.addFilter(prefixFilter);
        filterList.addFilter(singleColumnValueFilter);

        // 创建查询对象
        Scan scan = new Scan();
        scan.setFilter(filterList);
        Table table = connect.getTable(tableName);
        ResultScanner scanner = table.getScanner(scan);

        for (Result result : scanner) {
            byte[] value = result.getValue("cf1".getBytes(), "type".getBytes());
            System.out.println(new String(value, "utf8"));
        }

    }

8, 根据单个rowkey查询

    @Test
    public void testGet() throws IOException {
        Table table = connect.getTable(tableName);
        Get get = new Get("13899126419_201717".getBytes());

        Result result = table.get(get);
        Cell cell = result.getColumnLatestCell("cf1".getBytes(), "address".getBytes());
        System.out.println(new String(cell.getValueArray(), "utf8"));
    }

 

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