java app版本号对比

/**
 * 比较版本号的大小
 *  前者大则返回一个正数
 *  后者大返回一个负数
 *  相等则返回0
 * @param version1
 * @param version2
 * @return
 */
private static int compareVersion(String version1, String version2){
    if (version1 == null || version2 == null) {
        throw new RuntimeException("版本号不能为空");
    }
    String[] versionArray1 = version1.split("\\.");//注意此处为正则匹配,不能用.;
    String[] versionArray2 = version2.split("\\.");
    int idx = 0;
    int minLength = Math.min(versionArray1.length, versionArray2.length);//取最小长度值
    int diff = 0;
    while (idx < minLength
            && (diff = versionArray1[idx].length() - versionArray2[idx].length()) == 0//先比较长度
            && (diff = versionArray1[idx].compareTo(versionArray2[idx])) == 0) {//再比较字符
        ++idx;
    }
    //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;
    diff = (diff != 0) ? diff : versionArray1.length - versionArray2.length;
    return diff;
}

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