用 Java 对 hbase 进行CRUD增删改查操作
本文以HBase 0.90.2為例,介紹如何在Windows系統(tǒng),Eclipse IDE集成環(huán)境下,使用Java語言,進(jìn)行HBase客戶端編程,包含建立表、刪除表、插入記錄、刪除記錄、各種方式下的查詢操作等。
1. 準(zhǔn)備工作
1、下載后安裝jdk包(這里使用的是jdk-6u10-rc2-bin-b32-windows-i586-p-12_sep_2008);
2、下載eclipse,解壓到本地(這里使用的是eclipse-java-helios-SR2-win32);
3、下載HBase包,解壓安裝包到本地(這里使用的是hbase-0.90.2)。
2. 搭建開發(fā)環(huán)境
1、運(yùn)行Eclipse,創(chuàng)建一個(gè)新的Java工程“HBaseClient”,右鍵項(xiàng)目根目錄,選擇“Properties”->“Java Build Path”->“Library”->“Add External JARs”,將HBase解壓后根目錄下的hbase-0.90.2.jar、hbase-0.90.2-tests.jar和lib子目錄下所有jar包添加到本工程的Classpath下。
2、按照步驟1中的操作,將自己所連接的HBase的配置文件hbase-site.xml添加到本工程的Classpath中,如下所示為配置文件的一個(gè)示例。
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 | <configuration> <property> <name>hbase.rootdir</name> <value> hdfs://hostname:9000/hbase </value> </property> <property> <name>hbase.cluster.distributed</name> <value>true</value> </property> <property> <name>hbase.zookeeper.quorum</name> <value>*.*.*.*, *.*.*.*, *.*.*.*</value> </property> <propertyskipInDoc="true"> <name>hbase.defaults.for.version</name> <value>0.90.2</value> </property> </configuration> |
3、下面可以在Eclipse環(huán)境下進(jìn)行HBase編程了。
3. HBase基本操作代碼示例
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| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 | import java.io.IOException; import java.util.ArrayList; import java.util.List; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.hbase.HBaseConfiguration; import org.apache.hadoop.hbase.HColumnDescriptor; import org.apache.hadoop.hbase.HTableDescriptor; import org.apache.hadoop.hbase.KeyValue; import org.apache.hadoop.hbase.MasterNotRunningException; import org.apache.hadoop.hbase.ZooKeeperConnectionException; import org.apache.hadoop.hbase.client.Delete; import org.apache.hadoop.hbase.client.Get; import org.apache.hadoop.hbase.client.HBaseAdmin; import org.apache.hadoop.hbase.client.HTable; import org.apache.hadoop.hbase.client.Put; import org.apache.hadoop.hbase.client.Result; import org.apache.hadoop.hbase.client.ResultScanner; import org.apache.hadoop.hbase.client.Scan; import org.apache.hadoop.hbase.util.Bytes; public class CreateTable { ????private static Configuration conf = null; ????// 初始化配置 ????static { ????????conf = HBaseConfiguration.create(); ????} ????// 1、建表 ????public static void createTable(String tablename, String[] cfs) ????????????throws IOException { ????????HBaseAdmin admin = new HBaseAdmin(conf); ????????if (admin.tableExists(tablename)) { ????????????System.out.println("表已經(jīng)存在!"); ????????} else { ????????????HTableDescriptor tableDesc = new HTableDescriptor(tablename); ????????????for (int i = 0; i < cfs.length; i++) { ????????????????// 表建好后,列簇不能動(dòng)態(tài)增加,而列是可以動(dòng)態(tài)增加的,這是hbase伸縮性的一個(gè)體現(xiàn)。 ????????????????tableDesc.addFamily(new HColumnDescriptor(cfs[i])); ????????????} ????????????admin.createTable(tableDesc); ????????????System.out.println("表創(chuàng)建成功!"); ????????} ????} ????// 2、插入數(shù)據(jù) ????public static void writeRow(String tablename, String[] cfs) { ????????try { ????????????HTable table = new HTable(conf, tablename); ????????????Put put = new Put(Bytes.toBytes("rows1")); ????????????for (int j = 0; j < cfs.length; j++) { ????????????????put.add(Bytes.toBytes(cfs[j]), // 指定列簇 ????????????????????????Bytes.toBytes(String.valueOf("列1")),// 指定列名 ????????????????????????Bytes.toBytes("value_13"));// 指定列值 ????????????????put.add(Bytes.toBytes(cfs[j]), ????????????????????????Bytes.toBytes(String.valueOf("lie2")), ????????????????????????Bytes.toBytes("value_24")); ????????????????table.put(put); ????????????????System.out.println("插入數(shù)據(jù)成功"); ????????????} ????????} catch (IOException e) { ????????????e.printStackTrace(); ????????} ????} ????// 3、刪除一行數(shù)據(jù) ????public static void deleteRow(String tablename, String rowkey) ????????????throws IOException { ????????HTable table = new HTable(conf, tablename); ????????List list = new ArrayList(); ????????Delete d1 = new Delete(rowkey.getBytes()); ????????list.add(d1); ????????table.delete(list); ????????System.out.println("刪除行成功!"); ????} ????// 4、查找一行數(shù)據(jù) ????public static void selectRow(String tablename, String rowKey) ????????????throws IOException { ????????HTable table = new HTable(conf, tablename); ????????Get g = new Get(rowKey.getBytes()); ????????Result rs = table.get(g); ????????for (KeyValue kv : rs.raw()) { ????????????System.out.print(new String(kv.getRow()) + "? ");// 行號(hào) ????????????System.out.print(new String(kv.getFamily()) + ":");// 列簇名 ????????????System.out.print(new String(kv.getQualifier()) + "? ");// 列名 ????????????System.out.print(kv.getTimestamp() + "? ");// 時(shí)間戳 ????????????System.out.println(new String(kv.getValue()));// 單元格的值 ????????} ????} ????// 5、查找全部數(shù)據(jù) ????public static void scanerTable(String tablename) { ????????try { ????????????HTable table = new HTable(conf, tablename); ????????????Scan s = new Scan(); ????????????ResultScanner rs = table.getScanner(s); ????????????for (Result r : rs) { ????????????????KeyValue[] kv = r.raw(); ????????????????for (int i = 0; i < kv.length; i++) { ????????????????????System.out.print(new String(kv[i].getRow()) + "? "); ????????????????????System.out.print(new String(kv[i].getFamily()) + ":"); ????????????????????System.out.print(new String(kv[i].getQualifier()) + "? "); ????????????????????System.out.print(kv[i].getTimestamp() + "? "); ????????????????????System.out.println(new String(kv[i].getValue())); ????????????????} ????????????} ????????} catch (IOException e) { ????????????e.printStackTrace(); ????????} ????} ????// 6、刪除表 ????public static void deleteTable(String tablename) throws IOException { ????????try { ????????????HBaseAdmin admin = new HBaseAdmin(conf); ????????????admin.disableTable(tablename); ????????????admin.deleteTable(tablename); ????????????System.out.println("表刪除成功!"); ????????} catch (MasterNotRunningException e) { ????????????e.printStackTrace(); ????????} catch (ZooKeeperConnectionException e) { ????????????e.printStackTrace(); ????????} ????} ????public static void main(String[] args) throws IOException { ????????String[] cfs = "a,b,c".split(","); ????????// createTable("test01", cfs); ????????// writeRow("test01", cfs); ????????// deleteRow("test01", "rows1"); ????????// selectRow("test01", "rows2"); ????????// scanerTable("test01"); ????????// deleteTable("test01"); ????} } |
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