org.springframework.beans

## 类 BeanUtils

- java.lang.Object
- - org.springframework.beans.BeanUtils

-     public abstract class BeanUtils
      extends Object

  Static convenience methods for JavaBeans: for instantiating beans, checking bean property types, copying bean properties, etc.

  Mainly for use within the framework, but to some degree also useful for application classes.

  作者:
    Rod Johnson, Juergen Hoeller, Rob Harrop, Sam Brannen, Sebastien Deleuze

- - ### 构造器概要

    构造器
    构造器和说明
    `BeanUtils()`

  - ### 方法概要

    所有方法 静态方法 具体方法 已过时的方法
    限定符和类型 | 方法和说明
    --- | ---
    `static void` | `copyProperties(Object source, Object target)` Copy the property values of the given source bean into the target bean.
    `static void` | `copyProperties(Object source, Object target, Class<?> editable)` Copy the property values of the given source bean into the given target bean, only setting properties defined in the given "editable" class (or interface).
    `static void` | `copyProperties(Object source, Object target, String... ignoreProperties)` Copy the property values of the given source bean into the given target bean, ignoring the given "ignoreProperties".
    `static Method` | `findDeclaredMethod(Class<?> clazz, String methodName, Class<?>... paramTypes)` Find a method with the given method name and the given parameter types, declared on the given class or one of its superclasses.
    `static Method` | `findDeclaredMethodWithMinimalParameters(Class<?> clazz, String methodName)` Find a method with the given method name and minimal parameters (best case: none), declared on the given class or one of its superclasses.
    `static PropertyEditor` | `findEditorByConvention(Class<?> targetType)` Find a JavaBeans PropertyEditor following the 'Editor' suffix convention (e.g.
    `static Method` | `findMethod(Class<?> clazz, String methodName, Class<?>... paramTypes)` Find a method with the given method name and the given parameter types, declared on the given class or one of its superclasses.
    `static Method` | `findMethodWithMinimalParameters(Class<?> clazz, String methodName)` Find a method with the given method name and minimal parameters (best case: none), declared on the given class or one of its superclasses.
    `static Method` | `findMethodWithMinimalParameters(Method[] methods, String methodName)` Find a method with the given method name and minimal parameters (best case: none) in the given list of methods.
    `static <T> Constructor<T>` | `findPrimaryConstructor(Class<T> clazz)` Return the primary constructor of the provided class.
    `static PropertyDescriptor` | `findPropertyForMethod(Method method)` Find a JavaBeans `PropertyDescriptor` for the given method, with the method either being the read method or the write method for that bean property.
    `static PropertyDescriptor` | `findPropertyForMethod(Method method, Class<?> clazz)` Find a JavaBeans `PropertyDescriptor` for the given method, with the method either being the read method or the write method for that bean property.
    `static Class<?>` | `findPropertyType(String propertyName, Class<?>... beanClasses)` Determine the bean property type for the given property from the given classes/interfaces, if possible.
    `static PropertyDescriptor` | `getPropertyDescriptor(Class<?> clazz, String propertyName)` Retrieve the JavaBeans `PropertyDescriptors` for the given property.
    `static PropertyDescriptor[]` | `getPropertyDescriptors(Class<?> clazz)` Retrieve the JavaBeans `PropertyDescriptor`s of a given class.
    `static org.springframework.core.MethodParameter` | `getWriteMethodParameter(PropertyDescriptor pd)` Obtain a new MethodParameter object for the write method of the specified property.
    `static <T> T` | `instantiate(Class<T> clazz)` 已过时。 as of Spring 5.0, following the deprecation of `Class.newInstance()` in JDK 9
    `static <T> T` | `instantiateClass(Class<?> clazz, Class<T> assignableTo)` Instantiate a class using its no-arg constructor and return the new instance as the specified assignable type.
    `static <T> T` | `instantiateClass(Class<T> clazz)` Instantiate a class using its 'primary' constructor (for Kotlin classes, potentially having default arguments declared) or its default constructor (for regular Java classes, expecting a standard no-arg setup).
    `static <T> T` | `instantiateClass(Constructor<T> ctor, Object... args)` Convenience method to instantiate a class using the given constructor.
    `static boolean` | `isSimpleProperty(Class<?> clazz)` Check if the given type represents a "simple" property: a primitive, a String or other CharSequence, a Number, a Date, a URI, a URL, a Locale, a Class, or a corresponding array.
    `static boolean` | `isSimpleValueType(Class<?> clazz)` Check if the given type represents a "simple" value type: a primitive, an enum, a String or other CharSequence, a Number, a Date, a URI, a URL, a Locale or a Class.
    `static Method` | `resolveSignature(String signature, Class<?> clazz)` Parse a method signature in the form `methodName[([arg_list])]`, where `arg_list` is an optional, comma-separated list of fully-qualified type names, and attempts to resolve that signature against the supplied `Class`.

    - ### 从类继承的方法 java.lang.Object

      `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

- - ### 构造器详细资料

    - #### BeanUtils

          public BeanUtils()

  - ### 方法详细资料

    - #### instantiate

          @Deprecated
          public static <T> T instantiate(Class<T> clazz)
                                                throws BeanInstantiationException

      已过时。 as of Spring 5.0, following the deprecation of `Class.newInstance()` in JDK 9
      Convenience method to instantiate a class using its no-arg constructor.
      参数:
        `clazz` - class to instantiate
      返回:
        the new instance
      抛出:
        `BeanInstantiationException` - if the bean cannot be instantiated
      另请参阅:
        `Class.newInstance()`

    - #### instantiateClass

          public static <T> T instantiateClass(Class<T> clazz)
                                        throws BeanInstantiationException

      Instantiate a class using its 'primary' constructor (for Kotlin classes, potentially having default arguments declared) or its default constructor (for regular Java classes, expecting a standard no-arg setup).

      Note that this method tries to set the constructor accessible if given a non-accessible (that is, non-public) constructor.

      参数:
        `clazz` - the class to instantiate
      返回:
        the new instance
      抛出:
        `BeanInstantiationException` - if the bean cannot be instantiated. The cause may notably indicate a `NoSuchMethodException` if no primary/default constructor was found, a `NoClassDefFoundError` or other `LinkageError` in case of an unresolvable class definition (e.g. due to a missing dependency at runtime), or an exception thrown from the constructor invocation itself.
      另请参阅:
        `Constructor.newInstance(java.lang.Object...)`

    - #### instantiateClass

          public static <T> T instantiateClass(Class<?> clazz,
                                               Class<T> assignableTo)
                                        throws BeanInstantiationException

      Instantiate a class using its no-arg constructor and return the new instance as the specified assignable type.

      Useful in cases where the type of the class to instantiate (clazz) is not available, but the type desired (assignableTo) is known.

      Note that this method tries to set the constructor accessible if given a non-accessible (that is, non-public) constructor.

      参数:
        `clazz` - class to instantiate
        `assignableTo` - type that clazz must be assignableTo
      返回:
        the new instance
      抛出:
        `BeanInstantiationException` - if the bean cannot be instantiated
      另请参阅:
        `Constructor.newInstance(java.lang.Object...)`

    - #### instantiateClass

          public static <T> T instantiateClass(Constructor<T> ctor,
                                               Object... args)
                                        throws BeanInstantiationException

      Convenience method to instantiate a class using the given constructor.

      Note that this method tries to set the constructor accessible if given a non-accessible (that is, non-public) constructor, and supports Kotlin classes with optional parameters and default values.

      参数:
        `ctor` - the constructor to instantiate
        `args` - the constructor arguments to apply (use `null` for an unspecified parameter if needed for Kotlin classes with optional parameters and default values)
      返回:
        the new instance
      抛出:
        `BeanInstantiationException` - if the bean cannot be instantiated
      另请参阅:
        `Constructor.newInstance(java.lang.Object...)`

    - #### findPrimaryConstructor

          @Nullable
          public static <T> Constructor<T> findPrimaryConstructor(Class<T> clazz)

      Return the primary constructor of the provided class. For Kotlin classes, this returns the Java constructor corresponding to the Kotlin primary constructor (as defined in the Kotlin specification). Otherwise, in particular for non-Kotlin classes, this simply returns `null`.
      参数:
        `clazz` - the class to check
      从以下版本开始:
        5.0
      另请参阅:
        Kotlin docs

    - #### findMethod

          @Nullable
          public static Method findMethod(Class<?> clazz,
                                                     String methodName,
                                                     Class<?>... paramTypes)

      Find a method with the given method name and the given parameter types, declared on the given class or one of its superclasses. Prefers public methods, but will return a protected, package access, or private method too.

      Checks `Class.getMethod` first, falling back to `findDeclaredMethod`. This allows to find public methods without issues even in environments with restricted Java security settings.

      参数:
        `clazz` - the class to check
        `methodName` - the name of the method to find
        `paramTypes` - the parameter types of the method to find
      返回:
        the Method object, or `null` if not found
      另请参阅:
        `Class.getMethod(java.lang.String, java.lang.Class<?>...)`, `findDeclaredMethod(java.lang.Class<?>, java.lang.String, java.lang.Class<?>...)`

    - #### findDeclaredMethod

          @Nullable
          public static Method findDeclaredMethod(Class<?> clazz,
                                                             String methodName,
                                                             Class<?>... paramTypes)

      Find a method with the given method name and the given parameter types, declared on the given class or one of its superclasses. Will return a public, protected, package access, or private method.

      Checks `Class.getDeclaredMethod`, cascading upwards to all superclasses.

      参数:
        `clazz` - the class to check
        `methodName` - the name of the method to find
        `paramTypes` - the parameter types of the method to find
      返回:
        the Method object, or `null` if not found
      另请参阅:
        `Class.getDeclaredMethod(java.lang.String, java.lang.Class<?>...)`

    - #### findMethodWithMinimalParameters

          @Nullable
          public static Method findMethodWithMinimalParameters(Class<?> clazz,
                                                                          String methodName)
                                                                   throws IllegalArgumentException

      Find a method with the given method name and minimal parameters (best case: none), declared on the given class or one of its superclasses. Prefers public methods, but will return a protected, package access, or private method too.

      Checks `Class.getMethods` first, falling back to `findDeclaredMethodWithMinimalParameters`. This allows for finding public methods without issues even in environments with restricted Java security settings.

      参数:
        `clazz` - the class to check
        `methodName` - the name of the method to find
      返回:
        the Method object, or `null` if not found
      抛出:
        `IllegalArgumentException` - if methods of the given name were found but could not be resolved to a unique method with minimal parameters
      另请参阅:
        `Class.getMethods()`, `findDeclaredMethodWithMinimalParameters(java.lang.Class<?>, java.lang.String)`

    - #### findDeclaredMethodWithMinimalParameters

          @Nullable
          public static Method findDeclaredMethodWithMinimalParameters(Class<?> clazz,
                                                                                  String methodName)
                                                                           throws IllegalArgumentException

      Find a method with the given method name and minimal parameters (best case: none), declared on the given class or one of its superclasses. Will return a public, protected, package access, or private method.

      Checks `Class.getDeclaredMethods`, cascading upwards to all superclasses.

      参数:
        `clazz` - the class to check
        `methodName` - the name of the method to find
      返回:
        the Method object, or `null` if not found
      抛出:
        `IllegalArgumentException` - if methods of the given name were found but could not be resolved to a unique method with minimal parameters
      另请参阅:
        `Class.getDeclaredMethods()`

    - #### findMethodWithMinimalParameters

          @Nullable
          public static Method findMethodWithMinimalParameters(Method[] methods,
                                                                          String methodName)
                                                                   throws IllegalArgumentException

      Find a method with the given method name and minimal parameters (best case: none) in the given list of methods.
      参数:
        `methods` - the methods to check
        `methodName` - the name of the method to find
      返回:
        the Method object, or `null` if not found
      抛出:
        `IllegalArgumentException` - if methods of the given name were found but could not be resolved to a unique method with minimal parameters

    - #### resolveSignature

          @Nullable
          public static Method resolveSignature(String signature,
                                                           Class<?> clazz)

      Parse a method signature in the form `methodName[([arg_list])]`, where `arg_list` is an optional, comma-separated list of fully-qualified type names, and attempts to resolve that signature against the supplied `Class`.

      When not supplying an argument list (`methodName`) the method whose name matches and has the least number of parameters will be returned. When supplying an argument type list, only the method whose name and argument types match will be returned.

      Note then that `methodName` and `methodName()` are not resolved in the same way. The signature `methodName` means the method called `methodName` with the least number of arguments, whereas `methodName()` means the method called `methodName` with exactly 0 arguments.

      If no method can be found, then `null` is returned.

      参数:
        `signature` - the method signature as String representation
        `clazz` - the class to resolve the method signature against
      返回:
        the resolved Method
      另请参阅:
        `findMethod(java.lang.Class<?>, java.lang.String, java.lang.Class<?>...)`, `findMethodWithMinimalParameters(java.lang.Class<?>, java.lang.String)`

    - #### getPropertyDescriptors

          public static PropertyDescriptor[] getPropertyDescriptors(Class<?> clazz)
                                                             throws BeansException

      Retrieve the JavaBeans `PropertyDescriptor`s of a given class.
      参数:
        `clazz` - the Class to retrieve the PropertyDescriptors for
      返回:
        an array of `PropertyDescriptors` for the given class
      抛出:
        `BeansException` - if PropertyDescriptor look fails

    - #### getPropertyDescriptor

          @Nullable
          public static PropertyDescriptor getPropertyDescriptor(Class<?> clazz,
                                                                            String propertyName)
                                                                     throws BeansException

      Retrieve the JavaBeans `PropertyDescriptors` for the given property.
      参数:
        `clazz` - the Class to retrieve the PropertyDescriptor for
        `propertyName` - the name of the property
      返回:
        the corresponding PropertyDescriptor, or `null` if none
      抛出:
        `BeansException` - if PropertyDescriptor lookup fails

    - #### findPropertyForMethod

          @Nullable
          public static PropertyDescriptor findPropertyForMethod(Method method)
                                                                     throws BeansException

      Find a JavaBeans `PropertyDescriptor` for the given method, with the method either being the read method or the write method for that bean property.
      参数:
        `method` - the method to find a corresponding PropertyDescriptor for, introspecting its declaring class
      返回:
        the corresponding PropertyDescriptor, or `null` if none
      抛出:
        `BeansException` - if PropertyDescriptor lookup fails

    - #### findPropertyForMethod

          @Nullable
          public static PropertyDescriptor findPropertyForMethod(Method method,
                                                                            Class<?> clazz)
                                                                     throws BeansException

      Find a JavaBeans `PropertyDescriptor` for the given method, with the method either being the read method or the write method for that bean property.
      参数:
        `method` - the method to find a corresponding PropertyDescriptor for
        `clazz` - the (most specific) class to introspect for descriptors
      返回:
        the corresponding PropertyDescriptor, or `null` if none
      抛出:
        `BeansException` - if PropertyDescriptor lookup fails
      从以下版本开始:
        3.2.13

    - #### findEditorByConvention

          @Nullable
          public static PropertyEditor findEditorByConvention(@Nullable
                                                                         Class<?> targetType)

      Find a JavaBeans PropertyEditor following the 'Editor' suffix convention (e.g. "mypackage.MyDomainClass" -> "mypackage.MyDomainClassEditor").

      Compatible to the standard JavaBeans convention as implemented by `PropertyEditorManager` but isolated from the latter's registered default editors for primitive types.

      参数:
        `targetType` - the type to find an editor for
      返回:
        the corresponding editor, or `null` if none found

    - #### findPropertyType

          public static Class<?> findPropertyType(String propertyName,
                                                  @Nullable
                                                  Class<?>... beanClasses)

      Determine the bean property type for the given property from the given classes/interfaces, if possible.
      参数:
        `propertyName` - the name of the bean property
        `beanClasses` - the classes to check against
      返回:
        the property type, or `Object.class` as fallback

    - #### getWriteMethodParameter

          public static org.springframework.core.MethodParameter getWriteMethodParameter(PropertyDescriptor pd)

      Obtain a new MethodParameter object for the write method of the specified property.
      参数:
        `pd` - the PropertyDescriptor for the property
      返回:
        a corresponding MethodParameter object

    - #### isSimpleProperty

          public static boolean isSimpleProperty(Class<?> clazz)

      Check if the given type represents a "simple" property: a primitive, a String or other CharSequence, a Number, a Date, a URI, a URL, a Locale, a Class, or a corresponding array.

      Used to determine properties to check for a "simple" dependency-check.

      参数:
        `clazz` - the type to check
      返回:
        whether the given type represents a "simple" property
      另请参阅:
        `AbstractBeanDefinition.DEPENDENCY_CHECK_SIMPLE`, `AbstractAutowireCapableBeanFactory.checkDependencies(java.lang.String, org.springframework.beans.factory.support.AbstractBeanDefinition, java.beans.PropertyDescriptor[], org.springframework.beans.PropertyValues)`

    - #### isSimpleValueType

          public static boolean isSimpleValueType(Class<?> clazz)

      Check if the given type represents a "simple" value type: a primitive, an enum, a String or other CharSequence, a Number, a Date, a URI, a URL, a Locale or a Class.
      参数:
        `clazz` - the type to check
      返回:
        whether the given type represents a "simple" value type

    - #### copyProperties

          public static void copyProperties(Object source,
                                            Object target)
                                     throws BeansException

      Copy the property values of the given source bean into the target bean.

      Note: The source and target classes do not have to match or even be derived from each other, as long as the properties match. Any bean properties that the source bean exposes but the target bean does not will silently be ignored.

      This is just a convenience method. For more complex transfer needs, consider using a full BeanWrapper.

      参数:
        `source` - the source bean
        `target` - the target bean
      抛出:
        `BeansException` - if the copying failed
      另请参阅:
        `BeanWrapper`

    - #### copyProperties

          public static void copyProperties(Object source,
                                            Object target,
                                            Class<?> editable)
                                     throws BeansException

      Copy the property values of the given source bean into the given target bean, only setting properties defined in the given "editable" class (or interface).

      Note: The source and target classes do not have to match or even be derived from each other, as long as the properties match. Any bean properties that the source bean exposes but the target bean does not will silently be ignored.

      This is just a convenience method. For more complex transfer needs, consider using a full BeanWrapper.

      参数:
        `source` - the source bean
        `target` - the target bean
        `editable` - the class (or interface) to restrict property setting to
      抛出:
        `BeansException` - if the copying failed
      另请参阅:
        `BeanWrapper`

    - #### copyProperties

          public static void copyProperties(Object source,
                                            Object target,
                                            String... ignoreProperties)
                                     throws BeansException

      Copy the property values of the given source bean into the given target bean, ignoring the given "ignoreProperties".

      Note: The source and target classes do not have to match or even be derived from each other, as long as the properties match. Any bean properties that the source bean exposes but the target bean does not will silently be ignored.

      This is just a convenience method. For more complex transfer needs, consider using a full BeanWrapper.

      参数:
        `source` - the source bean
        `target` - the target bean
        `ignoreProperties` - array of property names to ignore
      抛出:
        `BeansException` - if the copying failed
      另请参阅:
        `BeanWrapper`