habse入门级别的笔记（摘抄）

Posted 2020-09-26 踏雪飞虹

最最常用的指令：

1.查看hbase有什么表 list

2.创建一个表： create ‘表名‘， ‘字段1’， ‘字段二’，。。。

3.往表中插入一条数据：put ‘表名‘，‘rowkey’，‘字段一：’，‘字段一栏目一名称’，‘字段一栏目一’，.....

4.查看整个表某列的内容：scan ‘表名‘，‘行名称’，‘列名称’

5.获得某行记录：get ‘表名’，‘rowkey‘

6.查看表中记录总数：count ‘表名‘

 

调用hbase接口应该注什么？

1.初始化配置(如)：

  Configuration conf = new Configuration();

  conf.set("hbase.zookeeper.quorum", "10.XXX.1.XXX,10.XXX.XXX.43,10.XXX.XXX.44"); 
  conf.set("hbase.rootdir", "hdfs://10.XXX.4.XXX:9000/user/hbase");
  conf.set("hbase.cluster.distributed", "true");
  conf.set("hbase.zookeeper.property.clientPort", "XXX");
  conf.set("hbase.master.port", "XXX");
  conf.set("hbase.master.info.port", "XXX");
  conf.set("hbase.client.write.buffer", "52428800");
  conf.set("hbase.zookeeper.property.dataDir", "/data/home/zookeeper");
  conf.set("hbase.tmp.dir", "/data/home/hbase_tmp");
  conf.set("zookeeper.znode.parent", "/hbase");
  conf.set("hbase.hregion.max.filesize", "1073741824");
  conf.set("hbase.regionserver.handler.count", "20");
  conf.set("zookeeper.session.timeout", "180000");  

这个相当于hbase客户端程序的site.xml配置文件

读写注意事项：

读写接口中传的参数都是二进制数据流，调用的时候注意转换

• Source Code

public static void readHbase(String table, String rowKey, String outfile, Configuration conf) throws IOException {

	byte[] ret = null;
		
	HTable htable = new HTable(conf, table);
		
	Get g = new Get(Bytes.toBytes(rowKey));
		
	System.out.println(g.toString());
		
	Result m = htable.get(g);
		
	ret = m.getValue("tarj_value".getBytes(), "Candy".getBytes());
		
        File out_file = new File(outfile);
                                                                 
        OutputStream out = null;

        try {
                 out = new FileOutputStream(out_file);
                 out.write(ret);
                 out.close();
            
        } catch (IOException e) {
        	
                 e.printStackTrace();
          
                 return;
        }   		
}
	
public static void writeHbase(String table, String rowKey, String infile, Configuration conf) throws IOException {
        File file = new File(infile);
        InputStream in = null;                                                                                                              
        long filelength = file.length();
        byte[] filecontent = null;
        try {
                 in = new FileInputStream(file);

                 filecontent = new byte[(int)filelength];
            
                 in.read(filecontent);

                 in.close();
        } catch (IOException e) {
                 e.printStackTrace();
        　　　　　return;
        }   
 
	Put put_rows = new Put(rowKey.getBytes());
		
	put_rows.add("tarj_value".getBytes(), "Candy".getBytes(), filecontent);
		
	HTable htable = new HTable(conf, table);
		
	htable.put(put_rows);       
}