程序包 cn.taketoday.expression

接口 TypeConverter

所有已知实现类:

StandardTypeConverter

public interface TypeConverter

A type converter can convert values between different types encountered during expression evaluation. This is an SPI for the expression parser; see ConversionService for the primary user API to Framework's conversion facilities.

从以下版本开始:

4.0

作者:

Andy Clement, Juergen Hoeller

方法概要

修饰符和类型	方法	说明
boolean	canConvert(TypeDescriptor sourceType, TypeDescriptor targetType)	Return true if the type converter can convert the specified type to the desired target type.
Object	convertValue(Object value, TypeDescriptor sourceType, TypeDescriptor targetType)	Convert (or coerce) a value from one type to another, for example from a boolean to a String.

方法详细资料

canConvert

boolean canConvert(@Nullable
 TypeDescriptor sourceType,
 TypeDescriptor targetType)

Return true if the type converter can convert the specified type to the desired target type.

参数:

sourceType - a type descriptor that describes the source type

targetType - a type descriptor that describes the requested result type

返回:

true if that conversion can be performed

convertValue

@Nullable
Object convertValue(@Nullable
 Object value,
 @Nullable
 TypeDescriptor sourceType,
 TypeDescriptor targetType)

Convert (or coerce) a value from one type to another, for example from a boolean to a String.

The TypeDescriptor parameters enable support for typed collections: A caller may prefer a List<Integer>, for example, rather than simply any List.

参数:

value - the value to be converted

sourceType - a type descriptor that supplies extra information about the source object

targetType - a type descriptor that supplies extra information about the requested result type

返回:

the converted value

抛出:

EvaluationException - if conversion failed or is not possible to begin with