Definitely the first way is the best practice, because in the second way you are hitting the database twice where you should actually hit it only once. This can cause performance issues. What you need to do is catch the exception EmptyResultDataAccessException and then return null back. Spring JDBC templates throws back an EmptyResultDataAccessException exception … Read more
You can do what you want. The javadoc of JdbcTemplate even clearly says it: Can be used within a service implementation via direct instantiation with a DataSource reference, or get prepared in an application context and given to services as bean reference.
By default, the JDBCTemplate does its own PreparedStatement internally, if you just use the .update(String sql, Object … args) form. Spring, and your database, will manage the compiled query for you, so you don’t have to worry about opening, closing, resource protection, etc. One of the saving graces of Spring. A link to Spring 2.5’s … Read more
you need to write this structure on your bean configuration (this is your datasource): <bean id=”hikariConfig” class=”com.zaxxer.hikari.HikariConfig”> <property name=”poolName” value=”springHikariCP” /> <property name=”connectionTestQuery” value=”SELECT 1″ /> <property name=”dataSourceClassName” value=”${hibernate.dataSourceClassName}” /> <property name=”maximumPoolSize” value=”${hibernate.hikari.maximumPoolSize}” /> <property name=”idleTimeout” value=”${hibernate.hikari.idleTimeout}” /> <property name=”dataSourceProperties”> <props> <prop key=”url”>${dataSource.url}</prop> <prop key=”user”>${dataSource.username}</prop> <prop key=”password”>${dataSource.password}</prop> </props> </property> </bean> <!– HikariCP configuration –> <bean … Read more
If you do all you can to make both implementations very fast, the JDBC template will probably be a bit faster, because it doesn’t have the overhead that Hibernate has. But it will probably take much more time and lines of code to implement. Hibernate has its learning curve, and you have to understand what … Read more
To populate a List of String, you need not use custom row mapper. Implement it using queryForList. List<String>data=jdbcTemplate.queryForList(query,String.class)
queryForMap is appropriate if you want to get a single row. You are selecting without a where clause, so you probably want to queryForList. The error is probably indicative of the fact that queryForMap wants one row, but you query is retrieving many rows. Check out the docs. There is a queryForList that takes just … Read more
When you use JdbcTemplate you give it SQL that has a ? placeholder for each parameter you want substituted into the SQL. When you assign parameters in the code you have to pass in arguments in an array and they get used in the order in which they appear in the array, like this: Object[] … Read more
Basic difference is with ResultsetExtractor you will need to iterate through the result set yourself, say in while loop. This interface provides you processing of the entire ResultSet at once. The implemetation of Interface method extractData(ResultSet rs) will contain that manual iteration code. See one implementation of ResultsetExtractor while some callback handlers like RowCallbackHandler, the … Read more
The SSL connection to the database is failing, try changing your datasource URL to: spring.datasource.url=jdbc:mysql://localhost:3306/employee_database?useSSL=false