`@SpringConversion`¶

@SpringConversion is an annotation that converts instances using the type conversion provided by the Spring Framework:

import io.github.scordio.junit.converters.SpringConversion;
import org.junit.jupiter.params.ParameterizedTest;
import org.junit.jupiter.params.provider.ValueSource;

@ParameterizedTest
@ValueSource(strings = "123, 456")
void test(@SpringConversion List<Integer> ints) {
    assertEquals(List.of(123, 456), ints);
}

The Spring conversion service provides a wide range of built-in converters for common Java types, including:

Primitives and their wrappers
Arrays
Collections (List, Set, Map, etc.)
Enums
Common value types (UUID, Currency, Locale, etc.)

In addition, the Spring format annotations are also supported:

@NumberFormat for formatting Number values such as Double and Long
@DurationFormat for formatting java.time.Duration values in ISO-8601 and simplified styles
@DateTimeFormat for formatting values such as java.util.Date, java.util.Calendar, and Long (for millisecond timestamps) as well as JSR-310 java.time types

Requirements¶

The annotation requires spring-core available in the test classpath:

Maven Gradle

<dependency>
  <groupId>org.springframework</groupId>
  <artifactId>spring-core</artifactId>
  <version>${spring-framework.version}</version>
  <scope>test</scope>
</dependency>

testImplementation("org.springframework:spring-core:${springFrameworkVersion}")

However, declaring this dependency is generally not required in a Spring application.

To use the Spring format annotations, spring-context must also be available:

Maven Gradle

<dependency>
  <groupId>org.springframework</groupId>
  <artifactId>spring-context</artifactId>
  <version>${spring-framework.version}</version>
  <scope>test</scope>
</dependency>

testImplementation("org.springframework:spring-context:${springFrameworkVersion}")

Examples¶

The following sections demonstrate some of the possible conversions. For a complete list of supported conversions, refer to the Spring Framework reference documentation.

Array → Array¶

Source Type	Target Declaration	Example
`String[]`	`@SpringConversion int[]`	`new String[] { "123", "456" }` → `new int[] { 123, 456 }`

Array → List¶

Source Type	Target Declaration	Example
`int[]`	`@SpringConversion List<Integer>`	`new int[] { 123, 456 }` → `List.of(123, 456)`
`Integer[]`	`@SpringConversion List<Integer>`	`new Integer[] { 123, 456 }` → `List.of(123, 456)`
`String[]`	`@SpringConversion List<Integer>`	`new String[] { "123", "456" }` → `List.of(123, 456)`

Array → Object¶

Source Type	Target Declaration	Example
`int[]`	`@SpringConversion int`	`new int[] { 123, 456 }` → `123`
`Integer[]`	`@SpringConversion int`	`new Integer[] { 123, 456 }` → `123`
`String[]`	`@SpringConversion int`	`new String[] { "123", "456" }` → `123`

Array → String¶

Source Type	Target Declaration	Example
`int[]`	`@SpringConversion String`	`new int[] { 123, 456 }` → `"123,456"`
`Integer[]`	`@SpringConversion String`	`new Integer[] { 123, 456 }` → `"123,456"`
`String[]`	`@SpringConversion String`	`new String[] { "123", "456" }` → `"123,456"`

List → List¶

Source Type	Target Declaration	Example
`List<String>`	`@SpringConversion List<Integer>`	`List.of("123", "456")` → `List.of(123, 456)`

Map → Map¶

Source Type	Target Declaration	Example
`Map<String, String>`	`@SpringConversion Map<Integer, Double>`	`Map.of("1", "123.4", "2", "234.5")` → `Map.of(1, 123.4, 2, 234.5)`

String → Double¶

Source Type	Target Declaration	Example
`String`	`@SpringConversion @NumberFormat(style = PERCENT) double`	`"42%"` → `0.42`

String → Duration¶

Source Type	Target Declaration	Example
`String`	`@SpringConversion @DurationFormat(style = SIMPLE) Duration`	`"42ms"` → `Duration.ofMillis(42)`

String → List¶

Source Type	Target Declaration	Example
`String`	`@SpringConversion List<Integer>`	`"123, 456"` → `List.of(123, 456)`

String → LocalDate¶

Source Type	Target Declaration	Example
`String`	`@SpringConversion LocalDate`	`"1970-01-01"` → `LocalDate.EPOCH`

String → LocalDateTime¶

Source Type	Target Declaration	Example
`String`	`@SpringConversion LocalDateTime`	`"1970-01-01T00:00:00"` → `LocalDateTime.of(LocalDate.EPOCH, LocalTime.MIDNIGHT)`

@SpringConversion¶