gitbase jdbc 连接简单说明

以下是Hikari 连接gitbase 的一个简单说明，可以参考，同时附带解决问题的思路

• 参考代码
  spring bean

 

@Bean

public DataSource dataSource(){

    HikariConfig config = new HikariConfig();

    config.setDriverClassName("com.mysql.cj.jdbc.Driver");

    config.setJdbcUrl("jdbc:mysql://<host>:3306/gitbase?useLocalSessionState=true&characterEncoding=UTF-8");

    config.setUsername("<username>");

    config.setPassword("<password>");

    HikariDataSource hikariDataSource = new HikariDataSource(config);

    return hikariDataSource;

}

• 问题说明
  如果使用默认的参数jdbc:mysql://<host>:3306/gitbase?characterEncoding=UTF-8 
  出现的问题如下

 

Caused by: java.sql.SQLException: Could not retrieve transaction isolation level from server

    at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:129) ~[mysql-connector-java-8.0.17.jar:8.0.17]

    at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:97) ~[mysql-connector-java-8.0.17.jar:8.0.17]

    at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:89) ~[mysql-connector-java-8.0.17.jar:8.0.17]

    at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:63) ~[mysql-connector-java-8.0.17.jar:8.0.17]

    at com.mysql.cj.jdbc.ConnectionImpl.getTransactionIsolation(ConnectionImpl.java:1214) ~[mysql-connector-java-8.0.17.jar:8.0.17]

    at com.zaxxer.hikari.pool.PoolBase.checkDefaultIsolation(PoolBase.java:479) ~[HikariCP-3.4.5.jar:na]

    at com.zaxxer.hikari.pool.PoolBase.checkDriverSupport(PoolBase.java:442) ~[HikariCP-3.4.5.jar:na]

    at com.zaxxer.hikari.pool.PoolBase.setupConnection(PoolBase.java:410) ~[HikariCP-3.4.5.jar:na]

    at com.zaxxer.hikari.pool.PoolBase.newConnection(PoolBase.java:363) ~[HikariCP-3.4.5.jar:na]

    at com.zaxxer.hikari.pool.PoolBase.newPoolEntry(PoolBase.java:206) ~[HikariCP-3.4.5.jar:na]

    at com.zaxxer.hikari.pool.HikariPool.createPoolEntry(HikariPool.java:477) ~[HikariCP-3.4.5.jar:na]

    at com.zaxxer.hikari.pool.HikariPool.checkFailFast(HikariPool.java:560) ~[HikariCP-3.4.5.jar:na]

跟进源码发现hikari 走了prepareCall，gitbase是不支持此特性的，而且gitbase 是不支持事务的，我们应该关闭此选项
hikari PoolBase.java 调用处理

 

private void checkDriverSupport(final Connection connection) throws SQLException

{

  if (!isValidChecked) {

     checkValidationSupport(connection);

     checkDefaultIsolation(connection);

 

     isValidChecked = true;

  }

}

加载mysql jdbc 源码之后发现了此方法
ConnectionImpl.java 文件

 

@Override

public int getTransactionIsolation() throws SQLException {

 

    synchronized (getConnectionMutex()) {

        // 此配置是核心

        if (!this.useLocalSessionState.getValue()) {

            String s = this.session.queryServerVariable(

                    versionMeetsMinimum(8, 0, 3) || (versionMeetsMinimum(5, 7, 20) && !versionMeetsMinimum(8, 0, 0)) ? "@@session.transaction_isolation"

                            : "@@session.tx_isolation");

 

            if (s != null) {

                Integer intTI = mapTransIsolationNameToValue.get(s);

                if (intTI != null) {

                    this.isolationLevel = intTI.intValue();

                    return this.isolationLevel;

                }

                throw SQLError.createSQLException(Messages.getString("Connection.12", new Object[] { s }), MysqlErrorNumbers.SQL_STATE_GENERAL_ERROR,

                        getExceptionInterceptor());

            }

            throw SQLError.createSQLException(Messages.getString("Connection.13"), MysqlErrorNumbers.SQL_STATE_GENERAL_ERROR, getExceptionInterceptor());

        }

 

        return this.isolationLevel;

    }

}

解决方法就很简单了，如果设置为true问题就可以解决了，因为默认为空

public ConnectionImpl(HostInfo hostInfo) throws SQLException {

 

        try {

            // Stash away for later, used to clone this connection for Statement.cancel and Statement.setQueryTimeout().

            ....

            this.useLocalSessionState = this.propertySet.getBooleanProperty(PropertyKey.useLocalSessionState);

            this.useServerPrepStmts = this.propertySet.getBooleanProperty(PropertyKey.useServerPrepStmts);

说明

以上只是一个思路，代码部分处理可能不同版本会不同，注意选择

参考资料

https://github.com/brettwooldridge/HikariCP