MatrixVariable (Spring Framework 5.2.12.RELEASE API)

```
@Target(PARAMETER)
@Retention(RUNTIME)
@Documented
public @interface MatrixVariable
```
Annotation which indicates that a method parameter should be bound to a name-value pair within a path segment. Supported for RequestMapping annotated handler methods.
If the method parameter type is Map and a matrix variable name is specified, then the matrix variable value is converted to a Map assuming an appropriate conversion strategy is available.
If the method parameter is Map<String, String> or MultiValueMap<String, String> and a variable name is not specified, then the map is populated with all matrix variable names and values.
Since:
3.2
Author:
Rossen Stoyanchev, Sam Brannen

Optional Element Summary

Optional Elements
Modifier and Type	Optional Element	Description
`String`	`defaultValue`	The default value to use as a fallback.
`String`	`name`	The name of the matrix variable.
`String`	`pathVar`	The name of the URI path variable where the matrix variable is located, if necessary for disambiguation (e.g.
`boolean`	`required`	Whether the matrix variable is required.
`String`	`value`	Alias for `name()`.

- Element Detail
  - value
```
@AliasFor("name")
String value
```
    Alias for name().
    Default:
    ""
- - name
```
@AliasFor("value")
String name
```
    The name of the matrix variable.
    Since:
    4.2
    See Also:
    value()
    Default:
    ""
- - pathVar
```
String pathVar
```
    The name of the URI path variable where the matrix variable is located, if necessary for disambiguation (e.g. a matrix variable with the same name present in more than one path segment).
    Default:
    "\n\t\t\n\t\t\n\ue000\ue001\ue002\n\t\t\t\t\n"
- - required
```
boolean required
```
    Whether the matrix variable is required.
    Default is true, leading to an exception being thrown in case the variable is missing in the request. Switch this to false if you prefer a null if the variable is missing.
    Alternatively, provide a defaultValue(), which implicitly sets this flag to false.
    Default:
    true
- - defaultValue
```
String defaultValue
```
    The default value to use as a fallback.
    Supplying a default value implicitly sets required() to false.
    Default:
    "\n\t\t\n\t\t\n\ue000\ue001\ue002\n\t\t\t\t\n"