java 版本比较

 1 public class version {
 2 
 3     public static int compareVersion(String version1, String version2) throws Exception {
 4         if (version1 == null || version2 == null) {
 5             throw new Exception("compareVersion error:illegal params.");
 6         }
 7         String[] versionArray1 = version1.split("\\.");//注意此处为正则匹配，不能用"."；
 8         String[] versionArray2 = version2.split("\\.");
 9         int idx = 0;
10         int minLength = Math.min(versionArray1.length, versionArray2.length);//取最小长度值
11         int diff = 0;
12         while (idx < minLength
13                 && (diff = versionArray1[idx].length() - versionArray2[idx].length()) == 0//先比较长度
14                 && (diff = versionArray1[idx].compareTo(versionArray2[idx])) == 0) {//再比较字符
15             ++idx;
16         }
17         //如果已经分出大小，则直接返回，如果未分出大小，则再比较位数，有子版本的为大；
18         diff = (diff != 0) ? diff : versionArray1.length - versionArray2.length;
19         return diff;
20     }
21 
22     public static void main(String [] args) throws Exception{
23         System.out.println(compareVersion("1.2.3", "1.2.3"));
24     }
25 }