问题描述
我有一个查询
SELECT * FROM dbName.dbTable
我正在使用准备好的语句执行查询。
这是HicariCP配置设置：
hconfig.setDriverClassName("com.mysql.jdbc.Driver");
hconfig.setJdbcUrl("jdbc:mysql://localhost/?useUnicode=true&characterEncoding=UTF8&cachePrepStmts=true&prepStmtCacheSize=250&useServerPrepStmts=true&rewriteBatchedStatements=true&continueBatchOnError=false&prepStmtCacheSqlLimit=2048");
hconfig.setUsername("user");
hconfig.setPassword("passwd");
hconfig.setMaximumPoolSize(10);
hconfig.setConnectionTimeout(60000);
HikariDataSource hikariDataSource= new HikariDataSource(hconfig);
客户端用法：
Client client;
client.executePreparedQuery(
"SELECT * FROM dbName.dbTable",
null,
new ResultSetBinder() {
@Override
public void bind(ResultSet resultSet) throws SQLException {
// binding the result goes here
}
});
Client类的相关方法（executePreparedQuery）：
Connection con = hikariDataSource.getConnection();
PreparedStatement ps = con.prepareStatement(sql);
ResultSet rs = null;
try {
if (psb != null) {
psb.bind(ps);
}
rs = ps.executeQuery();
while (rs.next()) {
if (rsb != null) {
rsb.bind(rs);
}
}
} finally {
close(rs, ps, con);
}
尽管要使用的数据库已在查询本身中进行了修饰，但是代码有时（并非总是如此！）会抛出java.sql.SQLException: No database selected.
HicariCP使用MySQL 5.6.22 。
可能是什么原因？
1楼
HicariCP Config设置：
添加=> hconfig.addDataSourceProperty（“ databaseName”，“ yourDatabaseName”）;
hconfig.setDriverClassName("com.mysql.jdbc.Driver");
hconfig.setJdbcUrl("jdbc:mysql://localhost/?useUnicode=true&characterEncoding=UTF8&cachePrepStmts=true&prepStmtCacheSize=250&useServerPrepStmts=true&rewriteBatchedStatements=true&continueBatchOnError=false&prepStmtCacheSqlLimit=2048");
hconfig.setUsername("user");
hconfig.setPassword("passwd");
hconfig.setMaximumPoolSize(10);
hconfig.setConnectionTimeout(60000);
hconfig.addDataSourceProperty("databaseName", "yourDatabaseName");
HikariDataSource hikariDataSource= new HikariDataSource(hconfig);
客户端用法：
更改为=> “ SELECT * FROM dbTable”
Client client;
client.executePreparedQuery(
"SELECT * FROM dbTable",
null,
new ResultSetBinder() {
@Override
public void bind(ResultSet resultSet) throws SQLException {
// binding the result goes here
}
});
希望它会有所帮助。