Spring(十三)--Spring泛型处理

Posted 2021-10-31 jazon@

• Java5类型接口-java.lang.reflect.Type

• Java泛型反射API

Spring泛型类型辅助类

核心API-org.springframework.core.GenericTypeResolver
1.处理类型相关(Type)相关方法

• resolveReturnType: 获取方法返回值的Type
• resolveType:

2.处理泛型参数类型(ParameterizedType)相关方法

• resolveReturnTypeArgument: 获取方法返回值的泛型参数
• resolveTypeArgument

/**
	 * Resolve the single type argument of the given generic interface against
	 * the given target class which is assumed to implement the generic interface
	 * and possibly declare a concrete type for its type variable.
	 * @param clazz the target class to check against
	 * @param genericIfc the generic interface or superclass to resolve the type argument from
	 * @return the resolved type of the argument, or {@code null} if not resolvable
	 */
/**
获取clazz在genericIfc的泛型参数
*/
	@Nullable
	public static Class<?> resolveTypeArgument(Class<?> clazz, Class<?> genericIfc) 

• resolveTypeArguments

/**
获取clazz在genericIfc的多个泛型参数
*/
public static Class<?>[] resolveTypeArguments(Class<?> clazz, Class<?> genericIfc)

• 处理泛型类型变量(TypeVariable)相关方法

/**
获取clazz的类定义的所有泛型Map,T -> 实际的T类型
*/
public static Map<TypeVariable, Type> getTypeVariableMap(Class<?> clazz);

Spring泛型优化实现-ResolvableType

org.springframework.core.ResolvableType

• 获取ResolvableType,工厂方法

ResolvableType resolvableType = ResolvableType.forClass(StuDao.class);

• 转换方法: as* 方法

// 获取
as(Class<?> type)
// 获取Collection的ResolvableType
asCollection()
// 获取Map的ResolvableType
asMap()

• 处理方法: resolve*方法

// 获取第一个泛型参数
resolveGeneric(int index)