java - CharSequence接口(interface)的toString()方法与Object类之间的区别

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Exact difference between CharSequence and String in java [duplicate]
                                
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toString()界面中的CharSequence方法和toString()类中的Object方法之间的真正区别是什么？

我知道String类默认情况下会实现CharSequence并扩展Object类。

但是String类是否将toString()的实现赋予CharSequence？如果是这样，那么当我们打印toString()时会调用哪个String版本？

最佳答案

toString()方法是在CharSequence接口中定义的，未实现。这样做是为了添加有关CharSequence实现需要遵循的要求的相关文档。

具体而言（Java 8 Update 141），CharSequence中的定义为：

/**
 * Returns a string containing the characters in this sequence in the same
 * order as this sequence.  The length of the string will be the length of
 * this sequence.
 *
 * @return  a string consisting of exactly this sequence of characters
 */
public String toString();

这描述了toString()对于CharSequence实现必须如何表现。

将此与Object中的javadoc进行对比：

/**
 * Returns a string representation of the object. In general, the
 * {@code toString} method returns a string that
 * "textually represents" this object. The result should
 * be a concise but informative representation that is easy for a
 * person to read.
 * It is recommended that all subclasses override this method.
 * <p>
 * The {@code toString} method for class {@code Object}
 * returns a string consisting of the name of the class of which the
 * object is an instance, the at-sign character `{@code @}', and
 * the unsigned hexadecimal representation of the hash code of the
 * object. In other words, this method returns a string equal to the
 * value of:
 * <blockquote>
 * <pre>
 * getClass().getName() + '@' + Integer.toHexString(hashCode())
 * </pre></blockquote>
 *
 * @return  a string representation of the object.
 */
public String toString()

关于java - CharSequence接口(interface)的toString()方法与Object类之间的区别，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/45940644/