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The SimpleJdbcTemplate has all the features of old JdbcTemplate and also support some features of Java 5 i.e varargs and autoboxing. It best suited when you need not to access all the feature of JdbcTemplate. It has a simpler API and basically construct to support java 5.Thats why it has more method to exploit varargs.
The getJdbcOperations() method is used to access those methods which are defined in JdbcTemplate. You have to call these method on SimpleJdbcTemplate . The main drawback is that you need to cast these methods as the methods on JdbcOperations interface are not generic.
Here are few examples to show how to use SimpleJdbcTemplate query() methods to query or extract data from database. In JdbcTemplate query(), you need to manually cast the returned result to desire object type, and pass an Object array as parameters. In SimpleJdbcTemplate, it is more user friendly and simple.
Note: The SimpleJdbcTemplate isn’t a replacement for JdbcTemplate, it’s just a java5-friendly supplement to it.
JdbcTemplate Style:-
// classic JdbcTemplate-style...
private JdbcTemplate jdbcTemplate;
public void setDataSource(DataSource dataSource) {
this.jdbcTemplate = new JdbcTemplate(dataSource);
}
public Actor findActor(String specialty, int age) {
String sql = "select id, first_name, last_name from T_ACTOR" +
" where specialty = ? and age = ?";
RowMapper mapper = new RowMapper() {
public Actor mapRow(ResultSet rs, int rowNum) throws SQLException {
Actor actor = new Actor();
actor.setId(rs.getLong("id"));
actor.setFirstName(rs.getString("first_name"));
actor.setLastName(rs.getString("last_name"));
return actor;
}
};
// notice the wrapping up of the argumenta in an array
return (Actor) jdbcTemplate.queryForObject(sql, new Object[] {specialty, age}, mapper);
}
Same thing in the form of SimplrJdbcTemplate style:-
// SimpleJdbcTemplate-style...
private SimpleJdbcTemplate simpleJdbcTemplate;
public void setDataSource(DataSource dataSource) {
this.simpleJdbcTemplate = new SimpleJdbcTemplate(dataSource);
}
public Actor findActor(String specialty, int age) {
String sql = "select id, first_name, last_name from T_ACTOR" +
" where specialty = ? and age = ?";
RowMapper mapper = new RowMapper() {
public Actor mapRow(ResultSet rs, int rowNum) throws SQLException {
Actor actor = new Actor();
actor.setId(rs.getLong("id"));
actor.setFirstName(rs.getString("first_name"));
actor.setLastName(rs.getString("last_name"));
return actor;
}
};
// notice the use of varargs since the parameter values now come
// after the RowMapper parameter
return this.simpleJdbcTemplate.queryForObject(sql, mapper, specialty, age);
}
Note:
The SimpleJdbcTemplate class only offers a subset of the methods exposed on the JdbcTemplate class. If you need to use a method from the JdbcTemplate that is not defined on the SimpleJdbcTemplate, you can always access the underlying JdbcTemplate by calling the getJdbcOperations() method on the SimpleJdbcTemplate, which then allows you to invoke the method that you want. The only downside is that the methods on the JdbcOperations interface are not generic, so you are back to casting and so on.
