Hadoop期末复习贴-Hbase

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Hbase是一个Hbase是一个分布式的、面向列的开源数据库
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讲完理论，现在进入Hbase用Java实现API
静态配置

• 创建表

    public static void CreateTable(String tablename, String info) throws IOException {
        TableName tableName = TableName.valueOf(tablename);
        Admin admin = connection.getAdmin(); //建表操作一定要通过connection.getAdmin产生一个admin
        TableDescriptorBuilder tableDescriptor = TableDescriptorBuilder.newBuilder(tableName);//表构造器
        ColumnFamilyDescriptor family = ColumnFamilyDescriptorBuilder.newBuilder(Bytes.toBytes("info")).build();//列构造器
        tableDescriptor.setColumnFamily(family);//表构造器中添加列构造器
        admin.createTable(tableDescriptor.build());//!!!一定要有这句
        admin.close();
    }

• 插入数据

    
    public static void InsertInfo(String tablename, String Row, String ColumnFamily, String Qualifier, String Value) throws IOException {
        TableName tableName = TableName.valueOf(tablename);
        Table table = connection.getTable(tableName);
        try {
            byte[] row = Bytes.toBytes(Row);
            Put put = new Put(row);
            put.addColumn(Bytes.toBytes(ColumnFamily), Bytes.toBytes(Qualifier), Bytes.toBytes(Value));
            table.put(put);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

• 查询数据

    public static void queryTableInfo(String tablename, String Row) throws IOException {
        TableName tableName = TableName.valueOf(tablename);
        Table table = connection.getTable(tableName);
        try {
            Get get = new Get(Bytes.toBytes(Row));//通过某一行Bytes的产生的get对象
            Result result = table.get(get);
            //返回值是Bytes
            byte[] valueBytes = result.getValue(Bytes.toBytes("info"), Bytes.toBytes("name"));
            String valueStr = new String(valueBytes, "utf-8");
            System.out.println(valueStr);

        } catch (Exception e) {
            e.printStackTrace();
        }
    }

• 删除表

    
    public static void deleteTable(String tablename) throws IOException {
        Admin admin = connection.getAdmin();
        TableName tableName = TableName.valueOf(tablename);
        admin.disableTable(tableName);
        admin.deleteTable(tableName);
    }

• 获得多行数据

    
    public static void batchGet(String tablename) throws Exception {
        TableName tableName = TableName.valueOf(tablename);//?
        Table table = connection.getTable(tableName);//获取Table对象

        String[] rows = new String[]{"1001", "1002"};
        List gets = new ArrayList<>();
        for (String str : rows) {
            gets.add(new Get(Bytes.toBytes(str)));
        }
        //可以直接将Get对象集合传入
        Result[] results = table.get(gets);
        for (Result result:results){
            System.out.println("Row:"+Bytes.toString(result.getRow()));
            for (Cell kv:result.rawCells()){ //将同一个Row的值遍历完
                String family = Bytes.toString(CellUtil.cloneFamily(kv));
                String qualifier = Bytes.toString(CellUtil.cloneQualifier(kv));
                String value = Bytes.toString(CellUtil.clonevalue(kv));
                System.out.println(family + ":" + qualifier + "t" + value);
            }
        }
    }

下午补看书补理论hhhh