Java 8 and Spring 4

On March 27, 2014, the Spring community was happy to announce the Spring Framework 4.0.3. The reason why is that it was the first release of the Spring Framework with Java 8 support. Since then, the Spring team worked very hard to provide major updates for the Spring Framework to be even more supportive towards Java 8. As of September 4, 2014, the Spring Framework 4.1 has arrived with even more support towards the Java community.

Lambda support in Spring 4.0

A good example to show the Lambda support in Spring is the JdbcTemplate class. If we would like to obtain female employees and map them as an instance of type Employee, we could do something like this:

JdbcTemplate jdbcTemplate = new JdbcTemplate(dataSource);

jdbcTemplate.query("SELECT first_name, last_name FROM employee WHERE gender = ?",
                   ps -> {ps.setString(1, "FEMALE");},
                   (rs) -> new Employee(rs.getString(1), rs.getString(2)));

The complete list of Spring 4.0 features can be found here.

Optional for injection points and MVC handler parameters in Spring 4.1

As of Spring 4.1, JDK 1.8’s java.util.Optional is now supported for @RequestParam, @RequestHeader, and @MatrixVariable controller method arguments. This means that while using Java’s Optional, you make sure that parameters are never null.

The following example shows an example of a @RequestParam in Spring MVC prior to version 4.1.

@RequestMapping(value="/iadvise")
public String findEmployee(@RequestParam(value = "employeeId") String employeeId) {
  StringBuilder response = new StringBuilder("id: ");
  response.append(employeeId.toUpperCase());
  return response.toString();
}

When calling the findEmployee method without providing an employeeId, the method will return a NullPointerException. This can be solved by Java’s Optional element.

@RequestMapping(value="/iadvise")
public String findEmployee(
  @RequestParam(value = "employeeId") Optional<String> employeeId){
  StringBuilder response = new StringBuilder("id: ");
  employeeId.ifPresent(value -> response.append(employeeId.toUpperCase()));
  return response.toString();
}

The same result can be achieved for the @RequestHeader, and @MatrixVariable annotations.

The complete list of Spring 4.1 features can be found here.

One thought on “Java 8 and Spring 4

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

About ongenbj