谢谢了,书上的看不懂.
------解决方案--------------------
完整的是不是这样的？
The String class provides methods for dealing with Unicode code points (i.e., characters), in addition to those for dealing with Unicode code units (i.e., char values)
如果是，那描述得也已经挺清楚了，Unicode code points 就是字符，Unicode code units 就是char变量的值。