spring boot连接clickhouse集群，实现故障节点自动切换

程序去连接clickhouse集群，要求当连接到故障节点时，可以自动去连接后面的可用节点，实现高可用。

新建ClickhouseDatasource，使用自定义的datasource

复制代码

@Bean(name="clickHouseDataSource")
 public DataSource clickHouseDataSource() throws Exception {
     ClickHouseDataSourceWithFailover datasource = new ClickHouseDataSourceWithFailover(ConnectInfo.ckIPs, userName, password, 5000);
     return datasource;
 }

自定义ClickHouseDataSourceWithFailover，连接失败时自动连接下一个节点

public class ClickHouseDataSourceWithFailover extends ClickHouseDataSource {
private final List<String> nodes;
private final String username;
private final String password;
private final int timeout;

复制代码

 public ClickHouseDataSourceWithFailover(List<String> nodes, String username, String password, int timeout) throws SQLException {
     super(String.format("jdbc:clickhouse://%s:8123/audit?connect_timeout=%d&socket_timeout=500000", nodes.get(0), timeout));
     this.nodes = nodes;
     this.username = username;
     this.password = password;
     this.timeout = timeout;
 }

 @Override
 public ClickHouseConnection getConnection() throws SQLException {
     for (String node : nodes) {
         try {
             String url = String.format("jdbc:clickhouse://%s:8123/db?connect_timeout=%d&socket_timeout=500000", node, timeout);
             Properties properties = new Properties();
             properties.put("username", username);
             properties.put("password", password);

             ClickHouseDataSource dataSource = new ClickHouseDataSource(url, properties);
             return dataSource.getConnection();
         } catch (SQLException e) {
             log.error("Failed to connect to node: {}, ex:{}", node, e);
         }
     }
     throw new SQLException("Unable to connect to any ClickHouse node.");
 }

}