比较两个字符串空,两种方法性能比较
测试 str.isEmpty()和 "".equals(str)两种判断的效率
比较次数999999999
str.isEmpty()用时2735(2.7秒)
"".equals(str)用时10516(10秒)
差别如此之大
public boolean equals(Object anObject) {if (this == anObject) { return true;}if (anObject instanceof String) { String anotherString = (String)anObject; int n = count; if (n == anotherString.count) {char v1[] = value;char v2[] = anotherString.value;int i = offset;int j = anotherString.offset;while (n-- != 0) { if (v1[i++] != v2[j++])return false;}return true; }}return false; }