hbase2.1.x 批量删除数据（delete）-马育民老师

# 说明

执行 `delete` 删除，可以传入 多个 rowkey

相当于 SQL 的：`delete from ... where id in ('1','2','3')`

### 底层实现

hbase java api，批量操作的底层，都是调用 `batch` 方法

批量 `delete()` 方法在 `HTable` 类中，声明如下：
```
@Override
public Result[] get(List<Get> gets) throws IOException {
    if (gets.size() == 1) {
      return new Result[]{get(gets.get(0))};
    }
    try {
      Object[] r1 = new Object[gets.size()];
      batch((List<? extends Row>)gets, r1, readRpcTimeoutMs);
      // Translate.
      Result [] results = new Result[r1.length];
      int i = 0;
      for (Object obj: r1) {
        // Batch ensures if there is a failure we get an exception instead
        results[i++] = (Result)obj;
      }
      return results;
    } catch (InterruptedException e) {
      throw (InterruptedIOException)new InterruptedIOException().initCause(e);
    }
}
```

**解释：** 将 多个 `Get` 对象放入 `List` 中，然后将 list 传入 `get` 方法，返回 `Result[]`

# 案例

删除 `rowkey` 是 `1001`、`1002` 的数据

相当于 SQL ：`delete from book where id in ('1001','1002')`

### 添加测试数据

清空表：
```
truncate 'book'
```

添加测试数据：

```
put 'book','1001','c1:title','htlm从入门到放弃'
put 'book','1001','c1:author','lucy'
put 'book','1001','c1:price','097.50'

put 'book','1002','c1:title','css从入门到放弃'
put 'book','1002','c1:author','lili'
put 'book','1002','c1:price','099.90'

put 'book','1003','c1:title','hadoop从入门到放弃'
put 'book','1003','c1:author','韩梅梅'
put 'book','1003','c1:price','190.00'
```

### 关键代码

```
public void delete(String tableName,String[] rowkeys) throws IOException {
    TableName tn=TableName.valueOf(tableName);
    //admin封装对表的操作，创建表、删除表、禁用表、启用表
    Table table = conn.getTable(tn);
    //封装Put对象
    List<Delete> list = new ArrayList<Delete>();

//遍历 rowkeys数组，创建 Delete对象，并将 rowkey 传入
    for(String item:rowkeys) {
        Delete delete = new Delete(Bytes.toBytes(item));
        list.add(delete);
    }

//调用delete方法进行删除
    table.delete(list);
    table.close();
}
```

### 测试

```
HbaseBatchUtils hbu = new HbaseBatchUtils();
hbu.connect();
//        hbu.putBatch();
String[] rowkeys = {"1001", "1002"};
//hbu.get("book", rowkeys);
hbu.delete("book",rowkeys);
hbu.close();
```

原文出处：http://www.malaoshi.top/show_1IX2JstkLQ56.html