shardingjdbc update

以下是使用Sharding-JDBC进行update操作的示例代码：

// 导入相关类
import org.apache.shardingsphere.api.sharding.standard.PreciseShardingAlgorithm;
import org.apache.shardingsphere.api.sharding.standard.RangeShardingAlgorithm;
import org.apache.shardingsphere.api.sharding.standard.StandardShardingStrategyConfiguration;
import org.apache.shardingsphere.shardingjdbc.api.ShardingDataSourceFactory;
import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import java.util.HashMap;
import java.util.Map;
import java.util.Properties;

// 创建数据源
DataSource dataSource = ShardingDataSourceFactory.createDataSource(createDataSourceMap(), createShardingRuleConfiguration(), new Properties());

// 获取数据库连接
try (Connection conn = dataSource.getConnection()) {
    // 创建PreparedStatement对象
    String sql = "UPDATE user SET name = ? WHERE id = ?";
    PreparedStatement ps = conn.prepareStatement(sql);
    // 设置参数
    ps.setString(1, "newName");
    ps.setInt(2, 1);
    // 执行更新操作
    ps.executeUpdate();
} catch (SQLException e) {
    e.printStackTrace();
}

// 创建数据源Map
private static Map<String, DataSource> createDataSourceMap() {
    Map<String, DataSource> dataSourceMap = new HashMap<>();
    // 添加主库数据源
    dataSourceMap.put("master", createDataSource("master"));
    // 添加从库数据源
    dataSourceMap.put("slave0", createDataSource("slave0"));
    dataSourceMap.put("slave1", createDataSource("slave1"));
    return dataSourceMap;
}

// 创建数据源
private static DataSource createDataSource(final String dataSourceName) {
    // 创建HikariDataSource对象
    HikariDataSource result = new HikariDataSource();
    // 配置数据源
    result.setDriverClassName("com.mysql.jdbc.Driver");
    result.setJdbcUrl(String.format("jdbc:mysql://localhost:3306/%s", dataSourceName));
    result.setUsername("root");
    result.setPassword("root");
    return result;
}

// 创建分片规则配置
private static ShardingRuleConfiguration createShardingRuleConfiguration() {
    // 创建分片规则配置对象
    ShardingRuleConfiguration shardingRuleConfig = new ShardingRuleConfiguration();
    // 配置分片表规则
    shardingRuleConfig.getTableRuleConfigs().add(createTableRuleConfiguration());
    // 配置分库策略
    shardingRuleConfig.setDefaultDatabaseShardingStrategyConfig(new StandardShardingStrategyConfiguration("id", new ModuloDatabaseShardingAlgorithm()));
    // 配置分表策略
    shardingRuleConfig.setDefaultTableShardingStrategyConfig(new StandardShardingStrategyConfiguration("id", new ModuloTableShardingAlgorithm()));
    return shardingRuleConfig;
}

// 创建分片表规则配置
private static TableRuleConfiguration createTableRuleConfiguration() {
    // 创建分片表规则配置对象
    TableRuleConfiguration result = new TableRuleConfiguration();
    // 配置逻辑表名
    result.setLogicTable("user");
    // 配置实际数据节点
    result.setActualDataNodes("master.user, slave0.user, slave1.user");
    // 配置分片键
    result.setKeyGeneratorColumnName("id");
    // 配置分片算法
    result.setTableShardingStrategyConfig(new StandardShardingStrategyConfiguration("id", new ModuloTableShardingAlgorithm()));
    return result;
}

// 创建取模分片算法
public class ModuloTableShardingAlgorithm implements PreciseShardingAlgorithm<Integer>, RangeShardingAlgorithm<Integer> {
    @Override
    public String doSharding(Collection<String> availableTargetNames, PreciseShardingValue<Integer> shardingValue) {
        for (String each : availableTargetNames) {
            if (each.endsWith(shardingValue.getValue() % 2 + "")) {
                return each;
            }
        }
        throw new IllegalArgumentException();
    }
    @Override
    public Collection<String> doSharding(Collection<String> availableTargetNames, RangeShardingValue<Integer> shardingValue) {
        Collection<String> result = new LinkedHashSet<>();
        for (Integer i = shardingValue.getValueRange().lowerEndpoint(); i <= shardingValue.getValueRange().upperEndpoint(); i++) {
            for (String each : availableTargetNames) {
                if (each.endsWith(i % 2 + "")) {
                    result.add(each);
                }
            }
        }
        return result;
    }
}