java.lang.Object
- org.springframework.util.Assert

```
public abstract class Assert
extends Object
```
Assertion utility class that assists in validating arguments.
Useful for identifying programmer errors early and clearly at runtime.
For example, if the contract of a public method states it does not allow null arguments, Assert can be used to validate that contract. Doing this clearly indicates a contract violation when it occurs and protects the class's invariants.
Typically used to validate method arguments rather than configuration properties, to check for cases that are usually programmer errors rather than configuration errors. In contrast to configuration initialization code, there is usually no point in falling back to defaults in such methods.
This class is similar to JUnit's assertion library. If an argument value is deemed invalid, an IllegalArgumentException is thrown (typically). For example:
```
 Assert.notNull(clazz, "The class must not be null");
 Assert.isTrue(i > 0, "The value must be greater than zero");
```
Mainly for internal use within the framework; consider Apache's Commons Lang for a more comprehensive suite of String utilities.
从以下版本开始:
1.1.2
作者:
Keith Donald, Juergen Hoeller, Sam Brannen, Colin Sampaleanu, Rob Harrop

构造器概要
构造器
构造器说明
Assert()

方法概要

所有方法静态方法具体方法已过时的方法
修饰符和类型	方法	说明
`static void`	`doesNotContain(String textToSearch, String substring)`	已过时。 as of 4.3.7, in favor of `doesNotContain(String, String, String)`
`static void`	`doesNotContain(String textToSearch, String substring, String message)`	Assert that the given text does not contain the given substring.
`static void`	`hasLength(String text)`	已过时。 as of 4.3.7, in favor of `hasLength(String, String)`
`static void`	`hasLength(String text, String message)`	Assert that the given String is not empty; that is, it must not be `null` and not the empty String.
`static void`	`hasText(String text)`	已过时。 as of 4.3.7, in favor of `hasText(String, String)`
`static void`	`hasText(String text, String message)`	Assert that the given String contains valid text content; that is, it must not be `null` and must contain at least one non-whitespace character.
`static void`	`isAssignable(Class<?> superType, Class<?> subType)`	Assert that `superType.isAssignableFrom(subType)` is `true`.
`static void`	`isAssignable(Class<?> superType, Class<?> subType, String message)`	Assert that `superType.isAssignableFrom(subType)` is `true`.
`static void`	`isInstanceOf(Class<?> type, Object obj)`	Assert that the provided object is an instance of the provided class.
`static void`	`isInstanceOf(Class<?> type, Object obj, String message)`	Assert that the provided object is an instance of the provided class.
`static void`	`isNull(Object object)`	已过时。 as of 4.3.7, in favor of `isNull(Object, String)`
`static void`	`isNull(Object object, String message)`	Assert that an object is `null`.
`static void`	`isTrue(boolean expression)`	已过时。 as of 4.3.7, in favor of `isTrue(boolean, String)`
`static void`	`isTrue(boolean expression, String message)`	Assert a boolean expression, throwing an `IllegalArgumentException` if the expression evaluates to `false`.
`static void`	`noNullElements(Object[] array)`	已过时。 as of 4.3.7, in favor of `noNullElements(Object[], String)`
`static void`	`noNullElements(Object[] array, String message)`	Assert that an array contains no `null` elements.
`static void`	`notEmpty(Object[] array)`	已过时。 as of 4.3.7, in favor of `notEmpty(Object[], String)`
`static void`	`notEmpty(Object[] array, String message)`	Assert that an array contains elements; that is, it must not be `null` and must contain at least one element.
`static void`	`notEmpty(Collection<?> collection)`	已过时。 as of 4.3.7, in favor of `notEmpty(Collection, String)`
`static void`	`notEmpty(Collection<?> collection, String message)`	Assert that a collection contains elements; that is, it must not be `null` and must contain at least one element.
`static void`	`notEmpty(Map<?,?> map)`	已过时。 as of 4.3.7, in favor of `notEmpty(Map, String)`
`static void`	`notEmpty(Map<?,?> map, String message)`	Assert that a Map contains entries; that is, it must not be `null` and must contain at least one entry.
`static void`	`notNull(Object object)`	已过时。 as of 4.3.7, in favor of `notNull(Object, String)`
`static void`	`notNull(Object object, String message)`	Assert that an object is not `null`.
`static void`	`state(boolean expression)`	已过时。 as of 4.3.7, in favor of `state(boolean, String)`
`static void`	`state(boolean expression, String message)`	Assert a boolean expression, throwing an `IllegalStateException` if the expression evaluates to `false`.

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
  - Assert
```
public Assert()
```
- 方法详细资料
  - state
```
public static void state(boolean expression,
                         String message)
```
    Assert a boolean expression, throwing an IllegalStateException if the expression evaluates to false.
    Call isTrue(boolean, java.lang.String) if you wish to throw an IllegalArgumentException on an assertion failure.
    Assert.state(id == null, "The id property must not already be initialized");
    参数:
    expression - a boolean expression
    message - the exception message to use if the assertion fails
    抛出:
    IllegalStateException - if expression is false
  - state
```
@Deprecated
public static void state(boolean expression)
```
    已过时。
    as of 4.3.7, in favor of state(boolean, String)
  - isTrue
```
public static void isTrue(boolean expression,
                          String message)
```
    Assert a boolean expression, throwing an IllegalArgumentException if the expression evaluates to false.
    Assert.isTrue(i > 0, "The value must be greater than zero");
    参数:
    expression - a boolean expression
    message - the exception message to use if the assertion fails
    抛出:
    IllegalArgumentException - if expression is false
  - isTrue
```
@Deprecated
public static void isTrue(boolean expression)
```
    已过时。
    as of 4.3.7, in favor of isTrue(boolean, String)
  - isNull
```
public static void isNull(Object object,
                          String message)
```
    Assert that an object is null.
    Assert.isNull(value, "The value must be null");
    参数:
    object - the object to check
    message - the exception message to use if the assertion fails
    抛出:
    IllegalArgumentException - if the object is not null
  - isNull
```
@Deprecated
public static void isNull(Object object)
```
    已过时。
    as of 4.3.7, in favor of isNull(Object, String)
  - notNull
```
public static void notNull(Object object,
                           String message)
```
    Assert that an object is not null.
    Assert.notNull(clazz, "The class must not be null");
    参数:
    object - the object to check
    message - the exception message to use if the assertion fails
    抛出:
    IllegalArgumentException - if the object is null
  - notNull
```
@Deprecated
public static void notNull(Object object)
```
    已过时。
    as of 4.3.7, in favor of notNull(Object, String)
  - hasLength
```
public static void hasLength(String text,
                             String message)
```
    Assert that the given String is not empty; that is, it must not be null and not the empty String.
    Assert.hasLength(name, "Name must not be empty");
    参数:
    text - the String to check
    message - the exception message to use if the assertion fails
    抛出:
    IllegalArgumentException - if the text is empty
    另请参阅:
    StringUtils.hasLength(java.lang.CharSequence)
  - hasLength
```
@Deprecated
public static void hasLength(String text)
```
    已过时。
    as of 4.3.7, in favor of hasLength(String, String)
  - hasText
```
public static void hasText(String text,
                           String message)
```
    Assert that the given String contains valid text content; that is, it must not be null and must contain at least one non-whitespace character.
    Assert.hasText(name, "'name' must not be empty");
    参数:
    text - the String to check
    message - the exception message to use if the assertion fails
    抛出:
    IllegalArgumentException - if the text does not contain valid text content
    另请参阅:
    StringUtils.hasText(java.lang.CharSequence)
  - hasText
```
@Deprecated
public static void hasText(String text)
```
    已过时。
    as of 4.3.7, in favor of hasText(String, String)
  - doesNotContain
```
public static void doesNotContain(String textToSearch,
                                  String substring,
                                  String message)
```
    Assert that the given text does not contain the given substring.
    Assert.doesNotContain(name, "rod", "Name must not contain 'rod'");
    参数:
    textToSearch - the text to search
    substring - the substring to find within the text
    message - the exception message to use if the assertion fails
    抛出:
    IllegalArgumentException - if the text contains the substring
  - doesNotContain
```
@Deprecated
public static void doesNotContain(String textToSearch,
                                  String substring)
```
    已过时。
    as of 4.3.7, in favor of doesNotContain(String, String, String)
  - notEmpty
```
public static void notEmpty(Object[] array,
                            String message)
```
    Assert that an array contains elements; that is, it must not be null and must contain at least one element.
    Assert.notEmpty(array, "The array must contain elements");
    参数:
    array - the array to check
    message - the exception message to use if the assertion fails
    抛出:
    IllegalArgumentException - if the object array is null or contains no elements
  - notEmpty
```
@Deprecated
public static void notEmpty(Object[] array)
```
    已过时。
    as of 4.3.7, in favor of notEmpty(Object[], String)
  - noNullElements
```
public static void noNullElements(Object[] array,
                                  String message)
```
    Assert that an array contains no null elements.
    Note: Does not complain if the array is empty!
    Assert.noNullElements(array, "The array must contain non-null elements");
    参数:
    array - the array to check
    message - the exception message to use if the assertion fails
    抛出:
    IllegalArgumentException - if the object array contains a null element
  - noNullElements
```
@Deprecated
public static void noNullElements(Object[] array)
```
    已过时。
    as of 4.3.7, in favor of noNullElements(Object[], String)
  - notEmpty
```
public static void notEmpty(Collection<?> collection,
                            String message)
```
    Assert that a collection contains elements; that is, it must not be null and must contain at least one element.
    Assert.notEmpty(collection, "Collection must contain elements");
    参数:
    collection - the collection to check
    message - the exception message to use if the assertion fails
    抛出:
    IllegalArgumentException - if the collection is null or contains no elements
  - notEmpty
```
@Deprecated
public static void notEmpty(Collection<?> collection)
```
    已过时。
    as of 4.3.7, in favor of notEmpty(Collection, String)
  - notEmpty
```
public static void notEmpty(Map<?,?> map,
                            String message)
```
    Assert that a Map contains entries; that is, it must not be null and must contain at least one entry.
    Assert.notEmpty(map, "Map must contain entries");
    参数:
    map - the map to check
    message - the exception message to use if the assertion fails
    抛出:
    IllegalArgumentException - if the map is null or contains no entries
  - notEmpty
```
@Deprecated
public static void notEmpty(Map<?,?> map)
```
    已过时。
    as of 4.3.7, in favor of notEmpty(Map, String)
  - isInstanceOf
```
public static void isInstanceOf(Class<?> type,
                                Object obj,
                                String message)
```
    Assert that the provided object is an instance of the provided class.
    Assert.instanceOf(Foo.class, foo, "Foo expected");
    参数:
    type - the type to check against
    obj - the object to check
    message - a message which will be prepended to provide further context. If it is empty or ends in ":" or ";" or "," or ".", a full exception message will be appended. If it ends in a space, the name of the offending object's type will be appended. In any other case, a ":" with a space and the name of the offending object's type will be appended.
    抛出:
    IllegalArgumentException - if the object is not an instance of type
  - isInstanceOf
```
public static void isInstanceOf(Class<?> type,
                                Object obj)
```
    Assert that the provided object is an instance of the provided class.
    Assert.instanceOf(Foo.class, foo);
    参数:
    type - the type to check against
    obj - the object to check
    抛出:
    IllegalArgumentException - if the object is not an instance of type
  - isAssignable
```
public static void isAssignable(Class<?> superType,
                                Class<?> subType,
                                String message)
```
    Assert that superType.isAssignableFrom(subType) is true.
    Assert.isAssignable(Number.class, myClass, "Number expected");
    参数:
    superType - the super type to check against
    subType - the sub type to check
    message - a message which will be prepended to provide further context. If it is empty or ends in ":" or ";" or "," or ".", a full exception message will be appended. If it ends in a space, the name of the offending sub type will be appended. In any other case, a ":" with a space and the name of the offending sub type will be appended.
    抛出:
    IllegalArgumentException - if the classes are not assignable
  - isAssignable
```
public static void isAssignable(Class<?> superType,
                                Class<?> subType)
```
    Assert that superType.isAssignableFrom(subType) is true.
    Assert.isAssignable(Number.class, myClass);
    参数:
    superType - the super type to check
    subType - the sub type to check
    抛出:
    IllegalArgumentException - if the classes are not assignable

类 Assert

构造器概要

方法概要

从类继承的方法 java.lang.Object

构造器详细资料

Assert

方法详细资料

state

state

isTrue

isTrue

isNull

isNull

notNull

notNull

hasLength

hasLength

hasText

hasText

doesNotContain

doesNotContain

notEmpty

notEmpty

noNullElements

noNullElements

notEmpty

notEmpty

notEmpty

notEmpty

isInstanceOf

isInstanceOf

isAssignable

isAssignable