谁能解释下面的代码String.java
,特别是为什么有三个if
语句(我已经标记//1
了//2
和//3
)?
private static class CaseInsensitiveComparator
implements Comparator<String>, java.io.Serializable {
// use serialVersionUID from JDK 1.2.2 for interoperability
private static final long serialVersionUID = 8575799808933029326L;
public int compare(String s1, String s2) {
int n1=s1.length(), n2=s2.length();
for (int i1=0, i2=0; i1<n1 && i2<n2; i1++, i2++) {
char c1 = s1.charAt(i1);
char c2 = s2.charAt(i2);
if (c1 != c2) {/////////////////////////1
c1 = Character.toUpperCase(c1);
c2 = Character.toUpperCase(c2);
if (c1 != c2) {/////////////////////////2
c1 = Character.toLowerCase(c1);
c2 = Character.toLowerCase(c2);
if (c1 != c2) {/////////////////////////3
return c1 - c2;
}
}
}
}
return n1 - n2;
}
}