HBase–經常使用過濾器篇

時間  2019-11-12
標籤 hbase 經常 使用 過濾器 欄目 Hadoop 简体版
原文   原文鏈接

過濾器的操做符

LESS  <
LESS_OR_EQUAL <=
EQUAL =
NOT_EQUAL <>
GREATER_OR_EQUAL >=
GREATER >
NO_OP no operation

 

比較器

BinaryComparator  按字節索引順序比較指定字節數組，採用Bytes.compareTo(byte[])
BinaryPrefixComparator 跟前面相同，只是比較左端的數據是否相同
NullComparator 判斷給定的是否爲空
BitComparator 按位比較 a BitwiseOp class 作異或，與，並操做
RegexStringComparator 提供一個正則的比較器，僅支持 EQUAL 和非EQUAL
SubstringComparator 判斷提供的子串是否出如今table的value中。

 

Hbase的過濾器分類

1.比較過濾器 Comparison Filters

1.1 RowFilter

構造函數：java

public RowFilter(org.apache.hadoop.hbase.filter.CompareFilter.CompareOp rowCompareOp, org.apache.hadoop.hbase.filter.WritableByteArrayComparable rowComparator) {}  
//選擇比較RowKey來確認返回訊息

 

示例代碼：express

public class RowFilterExample {  

  public static void main(String[] args) throws IOException {  
    Configuration conf = HBaseConfiguration.create();  

    HBaseHelper helper = HBaseHelper.getHelper(conf);  
    helper.dropTable("testtable");  
    helper.createTable("testtable", "colfam1", "colfam2");  
    System.out.println("Adding rows to table...");  
    helper.fillTable("testtable", 1, 100, 100, "colfam1", "colfam2");  

    HTable table = new HTable(conf, "testtable");  

    // vv RowFilterExample  
    Scan scan = new Scan();  
    scan.addColumn(Bytes.toBytes("colfam1"), Bytes.toBytes("col-0"));  

    Filter filter1 = new RowFilter(CompareFilter.CompareOp.LESS_OR_EQUAL, // co RowFilterExample-1-Filter1 Create filter, while specifying the comparison operator and comparator. Here an exact match is needed.  
      new BinaryComparator(Bytes.toBytes("row-22")));  
    scan.setFilter(filter1);  
    ResultScanner scanner1 = table.getScanner(scan);  
    // ^^ RowFilterExample  
    System.out.println("Scanning table #1...");  
    // vv RowFilterExample  
    for (Result res : scanner1) {  
      System.out.println(res);  
    }  
    scanner1.close();  

    Filter filter2 = new RowFilter(CompareFilter.CompareOp.EQUAL, // co RowFilterExample-2-Filter2 Another filter, this time using a regular expression to match the row keys.  
      new RegexStringComparator(".*-.5"));  
    scan.setFilter(filter2);  
    ResultScanner scanner2 = table.getScanner(scan);  
    // ^^ RowFilterExample  
    System.out.println("Scanning table #2...");  
    // vv RowFilterExample  
    for (Result res : scanner2) {  
      System.out.println(res);  
    }  
    scanner2.close();  

    Filter filter3 = new RowFilter(CompareFilter.CompareOp.EQUAL, // co RowFilterExample-3-Filter3 The third filter uses a substring match approach.  
      new SubstringComparator("-5"));  
    scan.setFilter(filter3);  
    ResultScanner scanner3 = table.getScanner(scan);  
    // ^^ RowFilterExample  
    System.out.println("Scanning table #3...");  
    // vv RowFilterExample  
    for (Result res : scanner3) {  
      System.out.println(res);  
    }  
    scanner3.close();  
    // ^^ RowFilterExample  
  }  
}

 

1.2 FamilyFilter

構造函數apache

public FamilyFilter(CompareOp familyCompareOp, WritableByteArrayComparable familyComparator) {}

 

示例代碼數組

//經過對比FamilyKey去獲取數據
public class FamilyFilterExample {  

  public static void main(String[] args) throws IOException {  
    Configuration conf = HBaseConfiguration.create();  

    HBaseHelper helper = HBaseHelper.getHelper(conf);  
    helper.dropTable("testtable");  
    helper.createTable("testtable", "colfam1", "colfam2", "colfam3", "colfam4");  
    System.out.println("Adding rows to table...");  
    helper.fillTable("testtable", 1, 10, 2, "colfam1", "colfam2", "colfam3", "colfam4");  

    HTable table = new HTable(conf, "testtable");  

    // vv FamilyFilterExample  
    Filter filter1 = new FamilyFilter(CompareFilter.CompareOp.LESS, // co FamilyFilterExample-1-Filter Create filter, while specifying the comparison operator and comparator.  
      new BinaryComparator(Bytes.toBytes("colfam3")));  

    Scan scan = new Scan();  
    scan.setFilter(filter1);  
    ResultScanner scanner = table.getScanner(scan); // co FamilyFilterExample-2-Scan Scan over table while applying the filter.  
    // ^^ FamilyFilterExample  
    System.out.println("Scanning table... ");  
    // vv FamilyFilterExample  
    for (Result result : scanner) {  
      System.out.println(result);  
    }  
    scanner.close();  

    Get get1 = new Get(Bytes.toBytes("row-5"));  
    get1.setFilter(filter1);  
    Result result1 = table.get(get1); // co FamilyFilterExample-3-Get Get a row while applying the same filter.  
    System.out.println("Result of get(): " + result1);  

    Filter filter2 = new FamilyFilter(CompareFilter.CompareOp.EQUAL,  
      new BinaryComparator(Bytes.toBytes("colfam3")));  
    Get get2 = new Get(Bytes.toBytes("row-5")); // co FamilyFilterExample-4-Mismatch Create a filter on one column family while trying to retrieve another.  
    get2.addFamily(Bytes.toBytes("colfam1"));  
    get2.setFilter(filter2);  
    Result result2 = table.get(get2); // co FamilyFilterExample-5-Get2 Get the same row while applying the new filter, this will return "NONE".  
    System.out.println("Result of get(): " + result2);  
    // ^^ FamilyFilterExample  
  }  
}

 

1.3QualifierFilter

構造函數app

public QualifierFilter(CompareOp qualifierCompareOp, WritableByteArrayComparable qualifierComparator) {  }

 

示例代碼：dom

//經過和列名比較，返回爲真的數據
// vv QualifierFilterExample  
   Filter filter = new QualifierFilter(CompareFilter.CompareOp.LESS_OR_EQUAL,  
     new BinaryComparator(Bytes.toBytes("col-2")));  

   Scan scan = new Scan();  
   scan.setFilter(filter);  
   ResultScanner scanner = table.getScanner(scan);  
   // ^^ QualifierFilterExample  
   System.out.println("Scanning table... ");  
   // vv QualifierFilterExample  
   for (Result result : scanner) {  
     System.out.println(result);  
   }  
   scanner.close();  

   Get get = new Get(Bytes.toBytes("row-5"));  
   get.setFilter(filter);  
   Result result = table.get(get);  
   System.out.println("Result of get(): " + result);

 

1.4 ValueFliter

public ValueFilter(CompareOp valueCompareOp, WritableByteArrayComparable valueComparator) { }

 

//對比列值獲取返回數據
Filter filter = new ValueFilter(CompareFilter.CompareOp.EQUAL, // co ValueFilterExample-1-Filter Create filter, while specifying the comparison operator and comparator.  
     new SubstringComparator(".4") );  

   Scan scan = new Scan();  
   scan.setFilter(filter); // co ValueFilterExample-2-SetFilter Set filter for the scan.  
   ResultScanner scanner = table.getScanner(scan);  
   // ^^ ValueFilterExample  
   System.out.println("Results of scan:");  
   // vv ValueFilterExample  
   for (Result result : scanner) {  
     for (KeyValue kv : result.raw()) {  
       System.out.println("KV: " + kv + ", Value: " + // co ValueFilterExample-3-Print1 Print out value to check that filter works.  
         Bytes.toString(kv.getValue()));  
     }  
   }  
   scanner.close();  

   Get get = new Get(Bytes.toBytes("row-5"));  
   get.setFilter(filter); // co ValueFilterExample-4-SetFilter2 Assign same filter to Get instance.  
   Result result = table.get(get);  
   // ^^ ValueFilterExample  
   System.out.println("Result of get: ");  
   // vv ValueFilterExample  
   for (KeyValue kv : result.raw()) {  
     System.out.println("KV: " + kv + ", Value: " +  
       Bytes.toString(kv.getValue()));  
   }

 

1.5 DependentColumnFilter

該過濾器有兩個參數 —— 列族和列修飾。 嘗試找到該列所在的每一行，並返回該行具備相同時間戳的所有鍵值對。若是某一行不包含指定的列，則該行的任何鍵值對都不返回。
該過濾器還能夠有一個可選布爾參數 —— dropDependentColumn. 若是爲true, 從屬的列不返回。
該過濾器還能夠有兩個可選參數 —— 一個比較操做符和一個值比較器，用於列族和修飾的進一步檢查。若是從屬的列找到，其值還必須經過值檢查，而後就是時間戳必須考慮。

 

示例代碼函數

package filters;  

// cc DependentColumnFilterExample Example using a filter to include only specific column families  
import org.apache.hadoop.conf.Configuration;  
import org.apache.hadoop.hbase.HBaseConfiguration;  
import org.apache.hadoop.hbase.KeyValue;  
import org.apache.hadoop.hbase.client.Get;  
import org.apache.hadoop.hbase.client.HTable;  
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.filter.BinaryPrefixComparator;  
import org.apache.hadoop.hbase.filter.CompareFilter;  
import org.apache.hadoop.hbase.filter.DependentColumnFilter;  
import org.apache.hadoop.hbase.filter.Filter;  
import org.apache.hadoop.hbase.filter.RegexStringComparator;  
import org.apache.hadoop.hbase.filter.WritableByteArrayComparable;  
import org.apache.hadoop.hbase.util.Bytes;  
import util.HBaseHelper;  

import java.io.IOException;  

public class DependentColumnFilterExample {  

  private static HTable table = null;  

  // vv DependentColumnFilterExample  
  private static void filter(boolean drop,  
      CompareFilter.CompareOp operator,  
      WritableByteArrayComparable comparator)  
  throws IOException {  
    Filter filter;  
    if (comparator != null) {  
      filter = new DependentColumnFilter(Bytes.toBytes("colfam1"), // co DependentColumnFilterExample-1-CreateFilter Create the filter with various options.  
        Bytes.toBytes("col-5"), drop, operator, comparator);  
    } else {  
      filter = new DependentColumnFilter(Bytes.toBytes("colfam1"),  
        Bytes.toBytes("col-5"), drop);  

    }  

    Scan scan = new Scan();  
    scan.setFilter(filter);  
    ResultScanner scanner = table.getScanner(scan);  
    // ^^ DependentColumnFilterExample  
    System.out.println("Results of scan:");  
    // vv DependentColumnFilterExample  
    for (Result result : scanner) {  
      for (KeyValue kv : result.raw()) {  
        System.out.println("KV: " + kv + ", Value: " +  
          Bytes.toString(kv.getValue()));  
      }  
    }  
    scanner.close();  

    Get get = new Get(Bytes.toBytes("row-5"));  
    get.setFilter(filter);  
    Result result = table.get(get);  
    // ^^ DependentColumnFilterExample  
    System.out.println("Result of get: ");  
    // vv DependentColumnFilterExample  
    for (KeyValue kv : result.raw()) {  
      System.out.println("KV: " + kv + ", Value: " +  
        Bytes.toString(kv.getValue()));  
    }  
    // ^^ DependentColumnFilterExample  
    System.out.println("");  
    // vv DependentColumnFilterExample  
  }  

  public static void main(String[] args) throws IOException {  
    // ^^ DependentColumnFilterExample  
    Configuration conf = HBaseConfiguration.create();  

    HBaseHelper helper = HBaseHelper.getHelper(conf);  
    helper.dropTable("testtable");  
    helper.createTable("testtable", "colfam1", "colfam2");  
    System.out.println("Adding rows to table...");  
    helper.fillTable("testtable", 1, 10, 10, true, "colfam1", "colfam2");  

    table = new HTable(conf, "testtable");  

    // vv DependentColumnFilterExample  
    filter(true, CompareFilter.CompareOp.NO_OP, null);  
    filter(false, CompareFilter.CompareOp.NO_OP, null); // co DependentColumnFilterExample-2-Filter Call filter method with various options.  
    filter(true, CompareFilter.CompareOp.EQUAL,  
      new BinaryPrefixComparator(Bytes.toBytes("val-5")));  
    filter(false, CompareFilter.CompareOp.EQUAL,  
      new BinaryPrefixComparator(Bytes.toBytes("val-5")));  
    filter(true, CompareFilter.CompareOp.EQUAL,  
      new RegexStringComparator(".*\\.5"));  
    filter(false, CompareFilter.CompareOp.EQUAL,  
      new RegexStringComparator(".*\\.5"));  
  }  
  // ^^ DependentColumnFilterExample}

 

2. Dedicated Filter

2.1 SingleColumValueFilter

//選定列簇和某一列，而後與列的value相比，正確的返回所有的row，注意若是某一行不含有該列，一樣返回，除非經過filterIfColumnMissing 設置成真。

//第一個構造函數至關於構建了一個BinaryComparator的實例。其餘的跟CompareFilter的參數含義同樣。  

SingleColumnValueFilter(byte[] family, byte[] qualifier, CompareOp compareOp, byte[] value){}

SingleColumnValueFilter(byte[] family, byte[] qualifier, CompareOp compareOp, WritableByteArrayComparable comparator){ }

//第一個構造函數至關於構建了一個BinaryComparator的實例。其餘的跟CompareFilter的參數含義同樣。  

boolean getFilterIfMissing()  
void setFilterIfMissing(boolean filterIfMissing)  
boolean getLatestVersionOnly()  
void setLatestVersionOnly(boolean latestVersionOnly)  

//若是 filterIfColumnMissing 標誌設爲真，若是該行沒有指定的列，那麼該行的全部列將不發出。缺省值爲假。
//若是 setLatestVersionOnly 標誌設爲假，將檢查此前的版本。缺省值爲真。實例以下：

// vv SingleColumnValueFilterExample  
  SingleColumnValueFilter filter = new SingleColumnValueFilter(  
    Bytes.toBytes("colfam1"),  
    Bytes.toBytes("col-5"),  
    CompareFilter.CompareOp.NOT_EQUAL,  
    new SubstringComparator("val-5"));  
  filter.setFilterIfMissing(true);  

  Scan scan = new Scan();  
  scan.setFilter(filter);  
  ResultScanner scanner = table.getScanner(scan);  
  // ^^ SingleColumnValueFilterExample  
  System.out.println("Results of scan:");  
  // vv SingleColumnValueFilterExample  
  for (Result result : scanner) {  
    for (KeyValue kv : result.raw()) {  
      System.out.println("KV: " + kv + ", Value: " +  
        Bytes.toString(kv.getValue()));  
    }  
  }  
  scanner.close();  

  Get get = new Get(Bytes.toBytes("row-6"));  
  get.setFilter(filter);  
  Result result = table.get(get);  
  System.out.println("Result of get: ");  
  for (KeyValue kv : result.raw()) {  
    System.out.println("KV: " + kv + ", Value: " +  
      Bytes.toString(kv.getValue()));  
  }

 

2.2 SingleColumnValueExcludeFilter

與SingleColumnValueFilter相反，與條件相符的將不會返回oop

2.2 PrefixFilter

全部的row的實例匹配prefix的時候返回結果集合性能

Filter filter = new PrefixFilter(Bytes.toBytes("row1"));  
Scan scan = new Scan();  
scan.setFilter(filter);  
ResultScanner scanner = table.getScanner(scan);  


for(Result result: scanner){  
    for(KeyValue kv: result.raw()) {  
        System.out.println("KV:" + kv + ", Value:"  + Bytes.toString(kv.getValue()));  
    }  
}  
scanner.close();  


Get get = new Get(Bytes.toBytes("row-5"));  
get.setFilter(filter);  
Result result = table.get(get);  
for(KeyValue kv : result.raw()){  
    System.out.println("KV:" + kv + ", Value:"  + Bytes.toString(kv.getValue()));  
}

 

2.4 PageFilter

//頁過濾
//經過設置pagesize能夠設置返回每一頁的page大小
//客戶端須要記錄上一次返回的row的Key值

package hbaseTest;  

import org.apache.hadoop.conf.Configuration;  
import org.apache.hadoop.hbase.HBaseConfiguration;  
import org.apache.hadoop.hbase.client.HTable;  
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.filter.Filter;  
import org.apache.hadoop.hbase.filter.PageFilter;  
import org.apache.hadoop.hbase.util.Bytes;  

import java.io.IOException;  

/** 
 * Hello world! 
 */  
public class PageFilterExample {  
    public static void main(String[] args) throws IOException {  
        Configuration config = HBaseConfiguration.create();  
        config.set("hbase.zookeeper.quorum", "QT-H-0038");  

        String tableName = "testTable";  
        String cfName = "colfam1";  
        final byte[] POSTFIX = new byte[] { 0x00 };  
        HTable table = new HTable(config, tableName);  
        Filter filter = new PageFilter(15);  
        byte[] lastRow = null;  
        int totalRows = 0;  
        while (true) {  
            Scan scan = new Scan();  
            scan.setFilter(filter);  
            if(lastRow != null){  
                //注意這裏添加了POSTFIX操做，否則死循環了  
                byte[] startRow = Bytes.add(lastRow,POSTFIX);  
                scan.setStartRow(startRow);  
            }  
            ResultScanner scanner = table.getScanner(scan);  
            int localRows = 0;  
            Result result;  
            while((result = scanner.next()) != null){  
                System.out.println(localRows++ + ":" + result);  
                totalRows ++;  
                lastRow = result.getRow();  
            }  
            scanner.close();  
            if(localRows == 0) break;  
        }  
        System.out.println("total rows:" + totalRows);  
    }  

}  


//由於hbase的row是字典序列排列的，所以上一次的lastrow須要添加額外的0(0x00)表示新的開始。另外startKey的那一行是包含在scan裏面的。
// final byte[] POSTFIX = new byte[] { 0x00 };

 

2.5 KeyOnlyFilter

由於一些應用只想獲取data數據，而不是真實的val，可使用這個過濾器。該過濾器經過this

KeyOnlyFilter(boolean lenAsVal)  
//lenAsVal默認爲假，表示不把val的長度做爲val。不然 val的長度將做爲val輸出。


 final byte[] POSTFIX = new byte[] { 0x00 };  
        HTable table = new HTable(config, tableName);  
        Filter filter = new KeyOnlyFilter(false);  
        byte[] lastRow = null;  
        int totalRows = 0;  


        Scan scan = new Scan();  
        scan.setFilter(filter);  
        ResultScanner scanner = table.getScanner(scan);  
        for(Result result: scanner){  
            for(KeyValue kv: result.raw()){  
                System.out.println(kv + ":" + Bytes.toString(kv.getValue()));  
            }  
        }

 

2.6 FirstKeyOnlyFilter

//在對hbase的表進行掃描的時候，若是指定了FirstKeyOnlyFilter過濾條件則僅僅會返回相同key的第一條kv。
//當對hbase中的表進行count，sum操做等集合操做的時候，使用FirstKeyOnlyFilter會帶來性能上的提高。

public class KeyOnlyFilterExample {  
    public static void main(String[] args) throws IOException {  
        Configuration config = HBaseConfiguration.create();  
        config.set("hbase.zookeeper.quorum", "QT-H-0038");  

        String tableName = "testTable";  
        String cfName = "colfam1";  
        final byte[] POSTFIX = new byte[] { 0x00 };  
        HTable table = new HTable(config, tableName);  
        Filter filter = new FirstKeyOnlyFilter();  
        byte[] lastRow = null;  
        int totalRows = 0;  

        Scan scan = new Scan();  
        scan.setFilter(filter);  
        ResultScanner scanner = table.getScanner(scan);  
        for(Result result: scanner){  
            for(KeyValue kv: result.raw()){  
                System.out.println(kv + ":" + Bytes.toString(kv.getValue()));  
            }  
        }  
    }  
}

 

返回的結果是
row-5/colfam1:qual1/1354673733503/Put/vlen=4:row1  
row1/colfam1:qual1/1354432930568/Put/vlen=4:val1  
row2/colfam1:qual2/1354432930568/Put/vlen=4:val3  

若是註釋掉過濾器的返回的結果是：
row-5/colfam1:qual1/1354673733503/Put/vlen=4:row1  
row1/colfam1:qual1/1354432930568/Put/vlen=4:val1  
row1/colfam1:qual2/1354435819120/Put/vlen=4:val2  
row2/colfam1:qual2/1354432930568/Put/vlen=4:val3

 

2.7 InclusiveStopFilter

//由於hbase的scan包含start-row不包含stop-row 若是使用這個過濾器咱們能夠包含stop-row
HTable table = new HTable(config, tableName);  

Filter filter  = new InclusiveStopFilter(Bytes.toBytes("row1"));  

Scan scan = new Scan();  
scan.setFilter(filter);  
scan.setStartRow(Bytes.toBytes("row-5"));  
ResultScanner scanner = table.getScanner(scan);  

for(Result result: scanner){  
    System.out.println(result);  
}  

//會看到row1包含在結果中了。

 

2.8 TimestampsFilter

當訪問某個Timestamp的新聞的時候，咱們須要以下的代碼：

TimestampsFilter(List<Long> timestamps)  
接受的參數的list參數，該Filter也能夠和scan.setTimeRange混合使用。例如：



// vv TimestampFilterExample  
    List<Long> ts = new ArrayList<Long>();  
    ts.add(new Long(5));  
    ts.add(new Long(10)); // co TimestampFilterExample-1-AddTS Add timestamps to the list.  
    ts.add(new Long(15));  
    Filter filter = new TimestampsFilter(ts);  

    Scan scan1 = new Scan();  
    scan1.setFilter(filter); // co TimestampFilterExample-2-AddFilter Add the filter to an otherwise default Scan instance.  
    ResultScanner scanner1 = table.getScanner(scan1);  
    // ^^ TimestampFilterExample  
    System.out.println("Results of scan #1:");  
    // vv TimestampFilterExample  
    for (Result result : scanner1) {  
      System.out.println(result);  
    }  
    scanner1.close();  

    Scan scan2 = new Scan();  
    scan2.setFilter(filter);  
    scan2.setTimeRange(8, 12); // co TimestampFilterExample-3-AddTSRange Also add a time range to verify how it affects the filter  
    ResultScanner scanner2 = table.getScanner(scan2);  
    // ^^ TimestampFilterExample  
    System.out.println("Results of scan #2:");  
    // vv TimestampFilterExample  
    for (Result result : scanner2) {  
      System.out.println(result);  
    }  
    scanner2.close();

 

2.9 ColumnCountGetFilter

//在scan時是無用的

 

2.10 ColumnPaginationFilter（下來用到的時候在仔細研究下）

/**
 * A filter, based on the ColumnCountGetFilter, takes two arguments: limit and offset.
 * This filter can be used for row-based indexing, where references to other tables are stored across many columns,
 * in order to efficient lookups and paginated results for end users.
 */
Filter filter = new ColumnPaginationFilter(5, 15);  

   Scan scan = new Scan();  
   scan.setFilter(filter);  
   ResultScanner scanner = table.getScanner(scan);  
   // ^^ ColumnPaginationFilterExample  
   System.out.println("Results of scan:");  
   // vv ColumnPaginationFilterExample  
   for (Result result : scanner) {  
     System.out.println(result);  
   }  
   scanner.close();

 

2.11 ColumnPrefixFilter

// 跟prefxiFilter類似，只是改爲了Column，實例以下：
// vv ColumnPaginationFilterExample  
      Filter filter = new ColumnPrefixFilter(Bytes.toBytes("qual2"));  

      Scan scan = new Scan();  
      scan.setFilter(filter);  
      ResultScanner scanner = table.getScanner(scan);  
      // ^^ ColumnPaginationFilterExample  
      System.out.println("Results of scan:");  
      // vv ColumnPaginationFilterExample  
      for (Result result : scanner) {  
          System.out.println(result);  
      }  
      scanner.close();  

// 值scan到與列值與前面匹配的數據。例如qual2匹配qual21。

 

2.12 RandomRowFilter

// 隨即的返回row的數據，構造函數爲
RandomRowFilter(float chance)  
// chance取值爲0到1.0，若是<0則爲空，若是>1則包含全部的行。

 

3. Decorating Filters

3.1 SkipFilter

//這個過濾器只做用到keyValueFilter上。KeyValueFilter會返回全部知足條件的row及對應的列。
而加上SkipFilter之後。會發現若是某一行的某一列不符合條件，則這一行所有不返回了。
public static void main(String[] args) throws IOException {  
   Configuration conf = HBaseConfiguration.create();  

   HBaseHelper helper = HBaseHelper.getHelper(conf);  
   helper.dropTable("testtable");  
   helper.createTable("testtable", "colfam1");  
   System.out.println("Adding rows to table...");  
   helper.fillTable("testtable", 1, 30, 5, 2, true, true, "colfam1");  

   HTable table = new HTable(conf, "testtable");  

   // vv SkipFilterExample  
   Filter filter1 = new ValueFilter(CompareFilter.CompareOp.NOT_EQUAL,  
     new BinaryComparator(Bytes.toBytes("val-0")));  

   Scan scan = new Scan();  
   scan.setFilter(filter1); // co SkipFilterExample-1-AddFilter1 Only add the ValueFilter to the first scan.  
   ResultScanner scanner1 = table.getScanner(scan);  
   // ^^ SkipFilterExample  
   System.out.println("Results of scan #1:");  
   int n = 0;  
   // vv SkipFilterExample  
   for (Result result : scanner1) {  
     for (KeyValue kv : result.raw()) {  
       System.out.println("KV: " + kv + ", Value: " +  
         Bytes.toString(kv.getValue()));  
       // ^^ SkipFilterExample  
       n++;  
       // vv SkipFilterExample  
     }  
   }  
   scanner1.close();  

   Filter filter2 = new SkipFilter(filter1);  

   scan.setFilter(filter2); // co SkipFilterExample-2-AddFilter2 Add the decorating skip filter for the second scan.  
   ResultScanner scanner2 = table.getScanner(scan);  
   // ^^ SkipFilterExample  
   System.out.println("Total KeyValue count for scan #1: " + n);  
   n = 0;  
   System.out.println("Results of scan #2:");  
   // vv SkipFilterExample  
   for (Result result : scanner2) {  
     for (KeyValue kv : result.raw()) {  
       System.out.println("KV: " + kv + ", Value: " +  
         Bytes.toString(kv.getValue()));  
       // ^^ SkipFilterExample  
       n++;  
       // vv SkipFilterExample  
     }  
   }  
   scanner2.close();  
   // ^^ SkipFilterExample  
   System.out.println("Total KeyValue count for scan #2: " + n);  
 }

 

3.2 WhileMatchFilters

至關於while執行，知道不match就break了返回了。
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