2019獨角獸企業重金招聘Python工程師標準>>>

TableStore數據準備：

首先需要添加TableStore的依賴

<dependency><groupId>com.aliyun.openservices</groupId><artifactId>tablestore</artifactId><version>4.10.2</version> </dependency>

運行項目時可能會出現SLF4J相關的紅字提示：

該提示不影響使用，如果覺得不爽的話，可以添加下面依賴去除：

<dependency><groupId>org.slf4j</groupId><artifactId>slf4j-simple</artifactId><version>1.7.26</version> </dependency>

TableStore的主鍵含自增類型，該類型為Interger，但是值很大，不能通過這中自增主鍵查詢數據，因此下面的SDK查詢操作都是不允許有自增主鍵的。

另外。表中的數據操作，對Column或者說屬性是有版本號這個概念的，該版本號以時間戳為準。當然，如果屬性需要存儲多個版本號的數據，在建表的時候要注意最大版本號這么一項，需要設置大于1。

1、根據主鍵查詢數據

import com.alicloud.openservices.tablestore.SyncClient; import com.alicloud.openservices.tablestore.model.Column; import com.alicloud.openservices.tablestore.model.GetRowRequest; import com.alicloud.openservices.tablestore.model.GetRowResponse; import com.alicloud.openservices.tablestore.model.PrimaryKey; import com.alicloud.openservices.tablestore.model.PrimaryKeyBuilder; import com.alicloud.openservices.tablestore.model.PrimaryKeyValue; import com.alicloud.openservices.tablestore.model.Row; import com.alicloud.openservices.tablestore.model.SingleRowQueryCriteria;public class Query {public static void main(String[] args) {final String endPoint = "實例訪問地址";final String accessKeyId = "accessKeyId";final String accessKeySecret = "accessKeySecret";// 實例名final String instanceName = "owlforest";SyncClient client = new SyncClient(endPoint, accessKeyId, accessKeySecret, instanceName);// 構造主鍵PrimaryKeyBuilder primaryKeyBuilder = PrimaryKeyBuilder.createPrimaryKeyBuilder();primaryKeyBuilder.addPrimaryKeyColumn("noteid", PrimaryKeyValue.fromLong(1));PrimaryKey primaryKey = primaryKeyBuilder.build();SingleRowQueryCriteria criteria = new SingleRowQueryCriteria("note", primaryKey);// 設置讀取最新版本criteria.setMaxVersions(1);// 讀取所有數據GetRowResponse getRowResponse = client.getRow(new GetRowRequest(criteria));Row row = getRowResponse.getRow();// 遍歷所有列Column[] columns = row.getColumns();for (Column column : columns) {System.out.println("Name:" + column.getName() + " Value:" + column.getValue());}}}

如果只需要讀取指定列，可以這樣設置：

// 設置讀取某些列 String[] a = { "author" }; criteria.addColumnsToGet(a); GetRowResponse getRowResponse2 = client.getRow(new GetRowRequest(criteria)); Row row2 = getRowResponse2.getRow(); Column[] columns2 = row2.getColumns(); for (Column column : columns2) {System.out.println("Name:" + column.getName() + " Value:" + column.getValue()); }

經測試，criteria.addColumnsToGet("author");這么設置運行也不會報錯，不過仍然會讀出所有屬性。

2、根據主鍵查詢數據-設置過濾器

可以表示的列與值的比較關系包括：EQUAL(=), NOT_EQUAL(!=), GREATER_THAN(>), GREATER_EQUAL(>=), LESS_THAN(<)以及LESS_EQUAL(<=)。

SyncClient client = new SyncClient(endPoint, accessKeyId, accessKeySecret, instanceName);// 構造主鍵 PrimaryKeyBuilder primaryKeyBuilder = PrimaryKeyBuilder.createPrimaryKeyBuilder(); primaryKeyBuilder.addPrimaryKeyColumn("noteid", PrimaryKeyValue.fromLong(1)); PrimaryKey primaryKey = primaryKeyBuilder.build();// 讀一行 SingleRowQueryCriteria criteria = new SingleRowQueryCriteria("note", primaryKey); // 設置讀取最新版本 criteria.setMaxVersions(1);//設置過濾器 SingleColumnValueFilter singleColumnValueFilter = new SingleColumnValueFilter( "author", CompareOperator.EQUAL, ColumnValue.fromString("I am zhangsan")); //如果不存在此列，也不返回 singleColumnValueFilter.setPassIfMissing(false); criteria.setFilter(singleColumnValueFilter);GetRowResponse getRowResponse = client.getRow(new GetRowRequest(criteria)); Row row = getRowResponse.getRow();if(row != null) {Column[] columns = row.getColumns();for(Column column : columns) { System.out.println("Name:" + column.getName() + " Value:" + column.getValue() + "\n");} }else {System.out.println("Row為空"); }

3、根據主鍵修改一行數據

修改前

SyncClient client = new SyncClient(endPoint, accessKeyId, accessKeySecret, instanceName);// 構造主鍵 PrimaryKeyBuilder primaryKeyBuilder = PrimaryKeyBuilder.createPrimaryKeyBuilder(); primaryKeyBuilder.addPrimaryKeyColumn("noteid", PrimaryKeyValue.fromLong(1)); PrimaryKey primaryKey = primaryKeyBuilder.build();RowUpdateChange rowUpdateChange = new RowUpdateChange("note", primaryKey); //修改author屬性 rowUpdateChange.put(new Column("author", ColumnValue.fromString("我叫張三"))); //新增屬性閱讀量view rowUpdateChange.put(new Column("view", ColumnValue.fromLong(10))); //刪除title屬性 rowUpdateChange.deleteColumns("title"); // 刪除某列的某一版本 //rowUpdateChange.deleteColumn(屬性名, 版本號);UpdateRowResponse response = client.updateRow(new UpdateRowRequest(rowUpdateChange));

修改后

4、新增一行數據

SyncClient client = new SyncClient(endPoint, accessKeyId, accessKeySecret, instanceName);// 構造主鍵 PrimaryKeyBuilder primaryKeyBuilder = PrimaryKeyBuilder.createPrimaryKeyBuilder(); primaryKeyBuilder.addPrimaryKeyColumn("noteid", PrimaryKeyValue.fromLong(1)); PrimaryKey primaryKey = primaryKeyBuilder.build();RowPutChange rowPutChange = new RowPutChange("note", primaryKey); long ts = System.currentTimeMillis();rowPutChange.addColumn(new Column("year", ColumnValue.fromLong(2019), ts)); rowPutChange.addColumn(new Column("month", ColumnValue.fromLong(3), ts));rowPutChange.addColumn(new Column("day", ColumnValue.fromString("天"), ts + 1)); rowPutChange.addColumn(new Column("day", ColumnValue.fromString("日"), ts + 2));client.putRow(new PutRowRequest(rowPutChange));

note表當中原先就有一條noteid為1的數據，執行PutRow之后，發現原數據被新數據直接覆蓋了。

5、期望原行不存在時寫入

經測試：當主鍵1存在時，添加條件RowExistenceExpectation.EXPECT_NOT_EXIST，執行PutRow會出現異常Failed RetriedCount:0 [ErrorCode]:OTSConditionCheckFail, [Message]:Condition check failed.

如果構造的主鍵不存在于數據庫，則可以正常插入。這個條件的使用場景比較讓人費解，先記下，興許后續會用上。

SyncClient client = new SyncClient(endPoint, accessKeyId, accessKeySecret, instanceName);// 構造主鍵 try {PrimaryKeyBuilder primaryKeyBuilder = PrimaryKeyBuilder.createPrimaryKeyBuilder();primaryKeyBuilder.addPrimaryKeyColumn("noteid", PrimaryKeyValue.fromLong(1));PrimaryKey primaryKey = primaryKeyBuilder.build();RowPutChange rowPutChange = new RowPutChange("note", primaryKey);rowPutChange.setCondition(new Condition(RowExistenceExpectation.EXPECT_NOT_EXIST));rowPutChange.addColumn(new Column("attr", ColumnValue.fromString("主鍵為1，看不到我"),System.currentTimeMillis()));client.putRow(new PutRowRequest(rowPutChange)); } catch (Exception e) {System.out.println(e.getMessage()); }

6、期望存在并某屬性滿足某條件時，覆蓋寫入行

同上，滿足條件是覆蓋該主鍵的數據，否則出錯

SyncClient client = new SyncClient(endPoint, accessKeyId, accessKeySecret, instanceName); PrimaryKeyBuilder primaryKeyBuilder = PrimaryKeyBuilder.createPrimaryKeyBuilder(); primaryKeyBuilder.addPrimaryKeyColumn("noteid", PrimaryKeyValue.fromLong(2)); PrimaryKey primaryKey = primaryKeyBuilder.build(); RowPutChange rowPutChange = new RowPutChange("note", primaryKey);try {// 期望原行存在，且屬性year=2019時插入Condition condition = new Condition(RowExistenceExpectation.EXPECT_EXIST);condition.setColumnCondition(new SingleColumnValueCondition("year", CompareOperator.EQUAL, ColumnValue.fromLong(2019)));rowPutChange.setCondition(condition);rowPutChange.addColumn(new Column("attr", ColumnValue.fromString("2019年")));client.putRow(new PutRowRequest(rowPutChange)); } catch (Exception e) {System.out.println(e.getMessage()); }

7、刪除一行數據

SyncClient client = new SyncClient(endPoint, accessKeyId, accessKeySecret, instanceName);// 構造主鍵 PrimaryKeyBuilder primaryKeyBuilder = PrimaryKeyBuilder.createPrimaryKeyBuilder(); primaryKeyBuilder.addPrimaryKeyColumn("noteid", PrimaryKeyValue.fromLong(10)); PrimaryKey primaryKey = primaryKeyBuilder.build();RowDeleteChange rowDeleteChange = new RowDeleteChange("note", primaryKey); client.deleteRow(new DeleteRowRequest(rowDeleteChange));

8、根據條件刪除數據

SyncClient client = new SyncClient(endPoint, accessKeyId, accessKeySecret, instanceName);// 構造主鍵 try {PrimaryKeyBuilder primaryKeyBuilder = PrimaryKeyBuilder.createPrimaryKeyBuilder();primaryKeyBuilder.addPrimaryKeyColumn("noteid", PrimaryKeyValue.fromLong(1));PrimaryKey primaryKey = primaryKeyBuilder.build();RowDeleteChange rowDeleteChange = new RowDeleteChange("note", primaryKey);Condition condition = new Condition(RowExistenceExpectation.EXPECT_EXIST);condition.setColumnCondition(new SingleColumnValueCondition("year",SingleColumnValueCondition.CompareOperator.EQUAL, ColumnValue.fromLong(2019)));rowDeleteChange.setCondition(condition);client.deleteRow(new DeleteRowRequest(rowDeleteChange)); } catch (Exception e) {System.out.println(e.getMessage()); }

轉載于:https://my.oschina.net/u/4108765/blog/3059588

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