Java 比较两个字符串的大小

static int compareTo(String s1, String s2) {
int len1 = s1.length();
int len2 = s2.length();
int lim = Math.min(len1, len2);
char[] charS1 = s1.toCharArray();
char[] charS2 = s2.toCharArray();
int k = 0;
while (k < lim) {
char c1 = charS1[k];
char c2 = charS2[k];
if (c1 != c2)
return c1 - c2;
k++;
}
return len1 - len2;
}