JDK源码阅读--AbstractStringBuilder

 

abstract class AbstractStringBuilder implements Appendable, CharSequence 

1  　　/**
2      * The value is used for character storage.
3      */
4     char[] value;
5 
6     /**
7      * The count is the number of characters used.
8      */
9     int count;

扩容：翻倍，不够取所需最小