java.lang.Object

cloud.opencode.base.reflect.ConstructorUtil

public final class ConstructorUtil extends Object

Constructor Utility Class 构造器工具类

Provides low-level constructor operation utilities with caching.

提供带缓存的底层构造器操作工具。

Features | 主要功能:

Constructor discovery with caching - 带缓存的构造器发现
Parameter type matching - 参数类型匹配
Constructor filtering by annotation - 按注解过滤构造器

Usage Examples | 使用示例:

Constructor<?> ctor = ConstructorUtil.getConstructor(User.class, String.class, int.class);
boolean hasDefault = ConstructorUtil.hasDefaultConstructor(User.class);

Security | 安全性:

Thread-safe: Yes (uses ConcurrentHashMap for caching) - 线程安全: 是（使用ConcurrentHashMap缓存）
Null-safe: No (caller must ensure non-null arguments) - 空值安全: 否（调用方须确保非空参数）

Performance | 性能特性:

Time complexity: O(1) for cached lookups; O(c) for first access where c is the number of constructors - 时间复杂度: 缓存命中时 O(1)；首次访问为 O(c)，c为构造器数量
Space complexity: O(c) for the cached constructors per class - 空间复杂度: O(c)，每类缓存构造器

Since:

JDK 25, opencode-base-reflect V1.0.0

Author:

Leon Soo www.LeonSoo.com

See Also:

Method Summary

Modifier and Type

Method

Description

static void

clearCache()

Clears constructor cache 清除构造器缓存

static void

clearCache(Class<?> clazz)

Clears cache for specific class 清除特定类的缓存

static <T> Constructor<T>

findMatchingConstructor(Class<T> clazz, Object... args)

Finds best matching constructor for arguments 查找最佳匹配的构造器

static <T> Constructor<T>

getConstructor(Class<T> clazz, Class<?>... parameterTypes)

Gets constructor by parameter types (cached) 按参数类型获取构造器（缓存）

static <T> Constructor<T>

getConstructorOrThrow(Class<T> clazz, Class<?>... parameterTypes)

Gets constructor or throws exception 获取构造器或抛出异常

static <T> List<Constructor<T>>

getConstructors(Class<T> clazz, Predicate<Constructor<T>> predicate)

Gets constructors matching predicate 获取匹配条件的构造器

static <T> List<Constructor<T>>

getConstructorsWithAnnotation(Class<T> clazz, Class<? extends Annotation> annotationClass)

Gets constructors with annotation 获取带注解的构造器

static <T> Constructor<T>[]

getDeclaredConstructors(Class<T> clazz)

Gets all declared constructors 获取所有声明的构造器

static <T> Constructor<T>

getDefaultConstructor(Class<T> clazz)

Gets default (no-arg) constructor 获取默认（无参）构造器

static int

getParameterCount(Constructor<?> constructor)

Gets constructor parameter count 获取构造器参数数量

static Class<?>[]

getParameterTypes(Constructor<?> constructor)

Gets constructor parameter types 获取构造器参数类型

static <T> List<Constructor<T>>

getPublicConstructors(Class<T> clazz)

Gets public constructors 获取公共构造器

static boolean

hasDefaultConstructor(Class<?> clazz)

Checks if class has default constructor 检查类是否有默认构造器

static boolean

isInstantiable(Class<?> clazz)

Checks if class is instantiable 检查类是否可实例化

static boolean

isPrivate(Constructor<?> constructor)

Checks if constructor is private 检查构造器是否为私有

static boolean

isPublic(Constructor<?> constructor)

Checks if constructor is public 检查构造器是否为公共

static <T> T

newInstance(Class<T> clazz)

Creates new instance using default constructor 使用默认构造器创建新实例

static <T> T

newInstance(Class<T> clazz, Object... args)

Creates new instance with arguments (auto-matching) 使用参数创建新实例（自动匹配）

static <T> T

newInstance(Constructor<T> constructor, Object... args)

Creates new instance using constructor 使用构造器创建新实例

static <T> Optional<T>

newInstanceSafe(Class<T> clazz)

Creates new instance safely 安全创建新实例

Methods inherited from class Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Details
- getDeclaredConstructors
  
  public static <T> Constructor<T>[] getDeclaredConstructors(Class<T> clazz)
  
  Gets all declared constructors 获取所有声明的构造器
  
  Type Parameters:
  
  T - the type | 类型
  
  Parameters:
  
  clazz - the class | 类
  
  Returns:
  
  array of constructors | 构造器数组
- getConstructor
  
  public static <T> Constructor<T> getConstructor(Class<T> clazz, Class<?>... parameterTypes)
  
  Gets constructor by parameter types (cached) 按参数类型获取构造器（缓存）
  
  Type Parameters:
  
  T - the type | 类型
  
  Parameters:
  
  clazz - the class | 类
  
  parameterTypes - the parameter types | 参数类型
  
  Returns:
  
  the constructor or null | 构造器或null
- getConstructorOrThrow
  
  public static <T> Constructor<T> getConstructorOrThrow(Class<T> clazz, Class<?>... parameterTypes)
  
  Gets constructor or throws exception 获取构造器或抛出异常
  
  Type Parameters:
  
  T - the type | 类型
  
  Parameters:
  
  clazz - the class | 类
  
  parameterTypes - the parameter types | 参数类型
  
  Returns:
  
  the constructor | 构造器
  
  Throws:
  
  OpenReflectException - if not found | 如果未找到
- getDefaultConstructor
  
  public static <T> Constructor<T> getDefaultConstructor(Class<T> clazz)
  
  Gets default (no-arg) constructor 获取默认（无参）构造器
  
  Type Parameters:
  
  T - the type | 类型
  
  Parameters:
  
  clazz - the class | 类
  
  Returns:
  
  the constructor or null | 构造器或null
- findMatchingConstructor
  
  public static <T> Constructor<T> findMatchingConstructor(Class<T> clazz, Object... args)
  
  Finds best matching constructor for arguments 查找最佳匹配的构造器
  
  Type Parameters:
  
  T - the type | 类型
  
  Parameters:
  
  clazz - the class | 类
  
  args - the arguments | 参数
  
  Returns:
  
  the constructor or null | 构造器或null
- getConstructors
  
  public static <T> List<Constructor<T>> getConstructors(Class<T> clazz, Predicate<Constructor<T>> predicate)
  
  Gets constructors matching predicate 获取匹配条件的构造器
  
  Type Parameters:
  
  T - the type | 类型
  
  Parameters:
  
  clazz - the class | 类
  
  predicate - the predicate | 谓词
  
  Returns:
  
  list of matching constructors | 匹配的构造器列表
- getConstructorsWithAnnotation
  
  public static <T> List<Constructor<T>> getConstructorsWithAnnotation(Class<T> clazz, Class<? extends Annotation> annotationClass)
  
  Gets constructors with annotation 获取带注解的构造器
  
  Type Parameters:
  
  T - the type | 类型
  
  Parameters:
  
  clazz - the class | 类
  
  annotationClass - the annotation class | 注解类
  
  Returns:
  
  list of constructors | 构造器列表
- getPublicConstructors
  
  public static <T> List<Constructor<T>> getPublicConstructors(Class<T> clazz)
  
  Gets public constructors 获取公共构造器
  
  Type Parameters:
  
  T - the type | 类型
  
  Parameters:
  
  clazz - the class | 类
  
  Returns:
  
  list of constructors | 构造器列表
- newInstance
  
  public static <T> T newInstance(Constructor<T> constructor, Object... args)
  
  Creates new instance using constructor 使用构造器创建新实例
  
  Type Parameters:
  
  T - the type | 类型
  
  Parameters:
  
  constructor - the constructor | 构造器
  
  args - the arguments | 参数
  
  Returns:
  
  the instance | 实例
- newInstance
  
  public static <T> T newInstance(Class<T> clazz)
  
  Creates new instance using default constructor 使用默认构造器创建新实例
  
  Type Parameters:
  
  T - the type | 类型
  
  Parameters:
  
  clazz - the class | 类
  
  Returns:
  
  the instance | 实例
- newInstance
  
  public static <T> T newInstance(Class<T> clazz, Object... args)
  
  Creates new instance with arguments (auto-matching) 使用参数创建新实例（自动匹配）
  
  Type Parameters:
  
  T - the type | 类型
  
  Parameters:
  
  clazz - the class | 类
  
  args - the arguments | 参数
  
  Returns:
  
  the instance | 实例
- newInstanceSafe
  
  public static <T> Optional<T> newInstanceSafe(Class<T> clazz)
  
  Creates new instance safely 安全创建新实例
  
  Type Parameters:
  
  T - the type | 类型
  
  Parameters:
  
  clazz - the class | 类
  
  Returns:
  
  Optional of instance | 实例的Optional
- getParameterTypes
  
  public static Class<?>[] getParameterTypes(Constructor<?> constructor)
  
  Gets constructor parameter types 获取构造器参数类型
  
  Parameters:
  
  constructor - the constructor | 构造器
  
  Returns:
  
  the parameter types | 参数类型
- getParameterCount
  
  public static int getParameterCount(Constructor<?> constructor)
  
  Gets constructor parameter count 获取构造器参数数量
  
  Parameters:
  
  constructor - the constructor | 构造器
  
  Returns:
  
  the parameter count | 参数数量
- isPublic
  
  public static boolean isPublic(Constructor<?> constructor)
  
  Checks if constructor is public 检查构造器是否为公共
  
  Parameters:
  
  constructor - the constructor | 构造器
  
  Returns:
  
  true if public | 如果是公共返回true
- isPrivate
  
  public static boolean isPrivate(Constructor<?> constructor)
  
  Checks if constructor is private 检查构造器是否为私有
  
  Parameters:
  
  constructor - the constructor | 构造器
  
  Returns:
  
  true if private | 如果是私有返回true
- hasDefaultConstructor
  
  public static boolean hasDefaultConstructor(Class<?> clazz)
  
  Checks if class has default constructor 检查类是否有默认构造器
  
  Parameters:
  
  clazz - the class | 类
  
  Returns:
  
  true if has default constructor | 如果有默认构造器返回true
- isInstantiable
  
  public static boolean isInstantiable(Class<?> clazz)
  
  Checks if class is instantiable 检查类是否可实例化
  
  Parameters:
  
  clazz - the class | 类
  
  Returns:
  
  true if instantiable | 如果可实例化返回true
- clearCache
  
  public static void clearCache()
  
  Clears constructor cache 清除构造器缓存
- clearCache
  
  public static void clearCache(Class<?> clazz)
  
  Clears cache for specific class 清除特定类的缓存
  
  Parameters:
  
  clazz - the class | 类

Class ConstructorUtil

Method Summary

Methods inherited from class Object

Method Details

getDeclaredConstructors

getConstructor

getConstructorOrThrow

getDefaultConstructor

findMatchingConstructor

getConstructors

getConstructorsWithAnnotation

getPublicConstructors

newInstance

newInstance

newInstance

newInstanceSafe

getParameterTypes

getParameterCount

isPublic

isPrivate

hasDefaultConstructor

isInstantiable

clearCache

clearCache