----------------------------------------------------------------------------- String类的compareTo方法的源码如下:
class String {
......
private final char value[]; // 数组常量表示数组大小(长度)不能变。
// 在底层会有一个转换,直接将字符串自动转换为一个字符数组。
public int compareTo(String anotherString) {
// this --> s1 --> "hello"
// anotherString --> s2 --> "hel"
int len1 = value.length; // this.value.length --> s1.toCharArray().length --> 5
int len2 = anotherString.value.length; // s2.value.length --> s2.toCharArray().length --> 3
int lim = Math.min(len1, len2); // Math.min(5,3); --> lim = 3;
char v1[] = value; // value --> s1.toCharArray()
char v2[] = anotherString.value;
// char v1[] = {'h','e','l','l','o'};
// char v2[] = {'h','e','l'};
int k = 0;
while (k < lim) {
char c1 = v1[k]; // c1 = 'h','e','l'
char c2 = v2[k]; // c2 = 'h','e','l'
if (c1 != c2) {
return c1 - c2;
}
k++;
}
return len1 - len2; // 5 - 3 = 2;
}
......
}
----------------------------------------------------------------------------- 示例代码:
String s1 = "hello"; String s2 = "hel"; System.out.println(s1.compareTo(s2)); // 2 -----------------------------------------------------------------------------