Hbase表的管理
HBaseAdmin是一个类表示管理，通过这个类可执行管理角色。HBaseAdmin这个类属于org.apache.hadoop.hbase.client包。
- 创建HBaseAdim实例
- 获取表实例
- 创建列簇描述
- 向表描述中加载列簇
- 调用HBaseAdmin创建表
后面可以通过HBaseAdmin对象判断表是否存在。
可以new一个Put对象，将rowkey传进去，并用Put对象向表中添加列和value值。
1 package top.tianyz.hbase.api;
2
3 import org.apache.hadoop.conf.Configuration;
4 import org.apache.hadoop.hbase.HColumnDescriptor;
5 import org.apache.hadoop.hbase.HTableDescriptor;
6 import org.apache.hadoop.hbase.TableName;
7 import org.apache.hadoop.hbase.client.*;
8 import org.apache.hadoop.hbase.util.Bytes;
9 import org.junit.Before;
10 import org.junit.Test;
11
12 import java.io.BufferedReader;
13 import java.io.FileReader;
14 import java.io.IOException;
15 import java.util.ArrayList;
16
17 public class Demo03HbaseApi {
18 private HConnection connection;
19 private HBaseAdmin hBaseAdmin;
20 @Before
21 public void Before() {
22 Configuration configuration = new Configuration();
23
24 configuration.set("hbase.zookeeper.quorum", "master:2181");
25
26 try {
27 connection = HConnectionManager.createConnection(configuration);
28 hBaseAdmin = new HBaseAdmin(configuration);
29
30 System.out.println("zk连接建立成功！");
31 } catch (IOException e) {
32 e.printStackTrace();
33 }
34 }
35
36 //创建表
37 @Test
38 public void CreateTable() throws IOException {
39
40 //HTableDescriptor student = hBaseAdmin.getTableDescriptor(TableName.valueOf("student"));
41 HTableDescriptor student =new HTableDescriptor(TableName.valueOf("student"));
42 HColumnDescriptor info = new HColumnDescriptor("info");
43 // info.setTimeToLive(10);
44 // info.setMaxVersions(10);
45 student.addFamily(info);
46 //创建表student
47 hBaseAdmin.createTable(student);
48 }
49
50 // 删除表
51 @Test
52 public void DropTable() {
53 try {
54 if (hBaseAdmin.tableExists("student")) {
55 hBaseAdmin.disableTable("student");
56 hBaseAdmin.deleteTable("student");
57 }
58 } catch (IOException e) {
59 e.printStackTrace();
60 }
61 }
62
63 //添加一列
64 @Test
65 public void PutOne() throws IOException {
66 HTableInterface student = connection.getTable("student");
67
68 Put put = new Put("001".getBytes());
69
70 put.add("info".getBytes(), "name".getBytes(), "张三".getBytes());
71
72 student.put(put);
73 }
74 // 增加多列
75 @Test
76 public void PutMore() throws IOException {
77
78 //批量插入数据
79 ArrayList<Put> puts = new ArrayList<Put>();
80
81 try {
82
83 //获取表的实例
84 HTableInterface student = connection.getTable("student");
85
86
87 BufferedReader bufferedReader = new BufferedReader(new FileReader("data/students.txt"));
88
89 String line;
90 while ((line = bufferedReader.readLine()) != null) {
91
92 String[] split = line.split(",");
93
94 String id = split[0];
95 String name = split[1];
96 Integer age = Integer.parseInt(split[2]);
97 String gender = split[3];
98 String clazz = split[4];
99
100
101 //构建put对象 一学号作为rowkey
102 Put put = new Put(id.getBytes());
103
104 //增加列
105 put.add("info".getBytes(), "name".getBytes(), name.getBytes("utf-8"));
106
107 //Bytes.toBytes(age) 将基本数据类型转换成字节数组
108 put.add("info".getBytes(), "age".getBytes(), Bytes.toBytes(age));
109
110 put.add("info".getBytes(), "gender".getBytes(), gender.getBytes());
111 put.add("info".getBytes(), "clazz".getBytes(), clazz.getBytes());
112
113 //将put放到集合中
114 puts.add(put);
115
116 }
117
118
119 //批量插入数据
120 student.put(puts);
121
122 } catch (Exception e) {
123 e.printStackTrace();
124 }
125 }
126
127 @Test
128 public void get() {
129 try {
130 HTableInterface student = connection.getTable("student");
131
132 //构建get对象 指定rowkey
133 Get get = new Get("1500100001".getBytes());
134
135 //执行查询 返回 result
136 Result result = student.get(get);
137
138 //取出rowkey
139 String id = Bytes.toString(result.getRow());
140
141
142 // 1、直接通过列名取值 如果列名不存在 返回对应类型的默认值
143 byte[] bytes = result.getValue("info".getBytes(), "name".getBytes());
144 //通过String的构造函数 构建字符串
145 //String name = new String(bytes, "utf-8");
146
147 //hbase 推荐方式
148 String name = Bytes.toString(bytes);
149
150 //int 类型 Bytes.toInt 转换
151 int age = Bytes.toInt(result.getValue("info".getBytes(), "age".getBytes()));
152
153 String gender = Bytes.toString(result.getValue("info".getBytes(), "gender".getBytes()));
154 String clazz = Bytes.toString(result.getValue("info".getBytes(), "clazz".getBytes()));
155
156 System.out.println(id + "\t" + name + "\t" + age + "\t" + gender + "\t" + clazz);
157
158 } catch (IOException e) {
159 e.printStackTrace();
160 }
161 }
162 }
