TableStore+java：单行操做

TableStore数据准备：

首先须要添加TableStore的依赖

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

运行项目时可能会出现SLF4J相关的红字提示：

该提示不影响使用，若是以为不爽的话，能够添加下面依赖去除：

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

TableStore的主键含自增类型，该类型为Interger，可是值很大，不能经过这中自增主键查询数据，所以下面的SDK查询操做都是不容许有自增主键的。

另外。表中的数据操做，对Column或者说属性是有版本号这个概念的，该版本号以时间戳为准。固然，若是属性须要存储多个版本号的数据，在建表的时候要注意最大版本号这么一项，须要设置大于1。

一、根据主键查询数据

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 = "实例访问地址";
        final String accessKeyId = "accessKeyId";
        final String accessKeySecret = "accessKeySecret";
        // 实例名
        final String instanceName = "owlforest";

        SyncClient client = new SyncClient(endPoint, accessKeyId, accessKeySecret, instanceName);

        // 构造主键
        PrimaryKeyBuilder primaryKeyBuilder = PrimaryKeyBuilder.createPrimaryKeyBuilder();
        primaryKeyBuilder.addPrimaryKeyColumn("noteid", PrimaryKeyValue.fromLong(1));
        PrimaryKey primaryKey = primaryKeyBuilder.build();

        SingleRowQueryCriteria criteria = new SingleRowQueryCriteria("note", primaryKey);

        // 设置读取最新版本
        criteria.setMaxVersions(1);
        // 读取全部数据
        GetRowResponse getRowResponse = client.getRow(new GetRowRequest(criteria));
        Row row = getRowResponse.getRow();
        // 遍历全部列
        Column[] columns = row.getColumns();
        for (Column column : columns) {
            System.out.println("Name:" + column.getName() + " Value:" + column.getValue());
        }
    }

}

若是只须要读取指定列，能够这样设置：

// 设置读取某些列
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());
}

经测试，criteria.addColumnsToGet("author");这么设置运行也不会报错，不过仍然会读出全部属性。

二、根据主键查询数据-设置过滤器

能够表示的列与值的比较关系包括：EQUAL(=), NOT_EQUAL(!=), GREATER_THAN(>), GREATER_EQUAL(>=), LESS_THAN(<)以及LESS_EQUAL(<=)。

SyncClient client = new SyncClient(endPoint, accessKeyId, accessKeySecret, instanceName);

// 构造主键
PrimaryKeyBuilder primaryKeyBuilder = PrimaryKeyBuilder.createPrimaryKeyBuilder();
primaryKeyBuilder.addPrimaryKeyColumn("noteid", PrimaryKeyValue.fromLong(1));
PrimaryKey primaryKey = primaryKeyBuilder.build();

// 读一行
SingleRowQueryCriteria criteria = new SingleRowQueryCriteria("note", primaryKey);
// 设置读取最新版本
criteria.setMaxVersions(1);

//设置过滤器
SingleColumnValueFilter singleColumnValueFilter = new SingleColumnValueFilter(
"author", CompareOperator.EQUAL, ColumnValue.fromString("I am zhangsan"));
//若是不存在此列，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为空");
}

三、根据主键修改一行数据

修改前

SyncClient client = new SyncClient(endPoint, accessKeyId, accessKeySecret, instanceName);

// 构造主键
PrimaryKeyBuilder primaryKeyBuilder = PrimaryKeyBuilder.createPrimaryKeyBuilder();
primaryKeyBuilder.addPrimaryKeyColumn("noteid", PrimaryKeyValue.fromLong(1));
PrimaryKey primaryKey = primaryKeyBuilder.build();

RowUpdateChange rowUpdateChange = new RowUpdateChange("note", primaryKey);
//修改author属性
rowUpdateChange.put(new Column("author", ColumnValue.fromString("我叫张三")));
//新增属性阅读量view
rowUpdateChange.put(new Column("view", ColumnValue.fromLong(10)));
//删除title属性
rowUpdateChange.deleteColumns("title");
// 删除某列的某一版本
//rowUpdateChange.deleteColumn(属性名, 版本号);
 
UpdateRowResponse response = client.updateRow(new UpdateRowRequest(rowUpdateChange));

修改后

四、新增一行数据

SyncClient client = new SyncClient(endPoint, accessKeyId, accessKeySecret, instanceName);

// 构造主键
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表当中原先就有一条noteid为1的数据，执行PutRow以后，发现原数据被新数据直接覆盖了。

五、指望原行不存在时写入

经测试：当主键1存在时，添加条件RowExistenceExpectation.EXPECT_NOT_EXIST，执行PutRow会出现异常Failed RetriedCount:0 [ErrorCode]:OTSConditionCheckFail, [Message]:Condition check failed.

若是构造的主键不存在于数据库，则能够正常插入。这个条件的使用场景比较让人费解，先记下，兴许后续会用上。

SyncClient client = new SyncClient(endPoint, accessKeyId, accessKeySecret, instanceName);

// 构造主键
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("主键为1，看不到我"),System.currentTimeMillis()));
    client.putRow(new PutRowRequest(rowPutChange));
} catch (Exception e) {
    System.out.println(e.getMessage());
}

六、指望存在并某属性知足某条件时，覆盖写入行

同上，知足条件是覆盖该主键的数据，不然出错

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 {
    // 指望原行存在，且属性year=2019时插入
    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());
}

七、删除一行数据

SyncClient client = new SyncClient(endPoint, accessKeyId, accessKeySecret, instanceName);

// 构造主键
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));

八、根据条件删除数据

SyncClient client = new SyncClient(endPoint, accessKeyId, accessKeySecret, instanceName);

// 构造主键
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());
}