是否有比较版本号的标准习语?我不能直接使用String compareTo，因为我还不知道点释放的最大数量是多少。我需要比较版本，并有以下保持正确:
1.0 < 1.1
1.0.1 < 1.1
1.9 < 1.10
当前回答
对于要显示基于版本号的强制更新警报的人，我有以下想法。这可能用于比较Android当前应用版本和firebase远程配置版本之间的版本。这并不是问题的确切答案，但这肯定会对某人有所帮助。
import java.util.List;
import java.util.ArrayList;
import java.util.Arrays;
public class Main
{
static String firebaseVersion = "2.1.3"; // or 2.1
static String appVersion = "2.1.4";
static List<String> firebaseVersionArray;
static List<String> appVersionArray;
static boolean isNeedToShowAlert = false;
public static void main (String[]args)
{
System.out.println ("Hello World");
firebaseVersionArray = new ArrayList<String>(Arrays.asList(firebaseVersion.split ("\\.")));
appVersionArray = new ArrayList<String>(Arrays.asList(appVersion.split ("\\.")));
if(appVersionArray.size() < firebaseVersionArray.size()) {
appVersionArray.add("0");
}
if(firebaseVersionArray.size() < appVersionArray.size()) {
firebaseVersionArray.add("0");
}
isNeedToShowAlert = needToShowAlert(); //Returns false
System.out.println (isNeedToShowAlert);
}
static boolean needToShowAlert() {
boolean result = false;
for(int i = 0 ; i < appVersionArray.size() ; i++) {
if (Integer.parseInt(appVersionArray.get(i)) == Integer.parseInt(firebaseVersionArray.get(i))) {
continue;
} else if (Integer.parseInt(appVersionArray.get(i)) > Integer.parseInt(firebaseVersionArray.get(i))){
result = false;
break;
} else if (Integer.parseInt(appVersionArray.get(i)) < Integer.parseInt(firebaseVersionArray.get(i))) {
result = true;
break;
}
}
return result;
}
}
您可以通过复制粘贴来运行此代码 https://www.onlinegdb.com/online_java_compiler
其他回答
这篇旧文章的另一个解决方案(对那些可能有帮助的人来说):
public class Version implements Comparable<Version> {
private String version;
public final String get() {
return this.version;
}
public Version(String version) {
if(version == null)
throw new IllegalArgumentException("Version can not be null");
if(!version.matches("[0-9]+(\\.[0-9]+)*"))
throw new IllegalArgumentException("Invalid version format");
this.version = version;
}
@Override public int compareTo(Version that) {
if(that == null)
return 1;
String[] thisParts = this.get().split("\\.");
String[] thatParts = that.get().split("\\.");
int length = Math.max(thisParts.length, thatParts.length);
for(int i = 0; i < length; i++) {
int thisPart = i < thisParts.length ?
Integer.parseInt(thisParts[i]) : 0;
int thatPart = i < thatParts.length ?
Integer.parseInt(thatParts[i]) : 0;
if(thisPart < thatPart)
return -1;
if(thisPart > thatPart)
return 1;
}
return 0;
}
@Override public boolean equals(Object that) {
if(this == that)
return true;
if(that == null)
return false;
if(this.getClass() != that.getClass())
return false;
return this.compareTo((Version) that) == 0;
}
}
Version a = new Version("1.1");
Version b = new Version("1.1.1");
a.compareTo(b) // return -1 (a<b)
a.equals(b) // return false
Version a = new Version("2.0");
Version b = new Version("1.9.9");
a.compareTo(b) // return 1 (a>b)
a.equals(b) // return false
Version a = new Version("1.0");
Version b = new Version("1");
a.compareTo(b) // return 0 (a=b)
a.equals(b) // return true
Version a = new Version("1");
Version b = null;
a.compareTo(b) // return 1 (a>b)
a.equals(b) // return false
List<Version> versions = new ArrayList<Version>();
versions.add(new Version("2"));
versions.add(new Version("1.0.5"));
versions.add(new Version("1.01.0"));
versions.add(new Version("1.00.1"));
Collections.min(versions).get() // return min version
Collections.max(versions).get() // return max version
// WARNING
Version a = new Version("2.06");
Version b = new Version("2.060");
a.equals(b) // return false
编辑:
@daiscog:谢谢你的评论，这段代码是为Android平台开发的，由谷歌推荐，方法“匹配”检查整个字符串，不像Java使用监管模式。(Android文档- JAVA文档)
最好的方法是重用现有代码， 使用Maven的ComparableVersion类
优点:
Apache许可证，版本2.0， 测试, 在多个项目中使用(复制)，如spring-security-core, jboss等 多个特性 它已经是java.lang。可比的了 只是复制粘贴一个类，没有第三方依赖
不要包含对maven-artifact的依赖项，因为那会拉动各种传递依赖项
也许有人会对我的解决方案感兴趣:
class Version private constructor(private val versionString: String) : Comparable<Version> {
private val major: Int by lazy { versionString.split(".")[0].toInt() }
private val minor: Int by lazy { versionString.split(".")[1].toInt() }
private val patch: Int by lazy {
val splitArray = versionString.split(".")
if (splitArray.size == 3)
splitArray[2].toInt()
else
0
}
override fun compareTo(other: Version): Int {
return when {
major > other.major -> 1
major < other.major -> -1
minor > other.minor -> 1
minor < other.minor -> -1
patch > other.patch -> 1
patch < other.patch -> -1
else -> 0
}
}
override fun equals(other: Any?): Boolean {
if (other == null || other !is Version) return false
return compareTo(other) == 0
}
override fun hashCode(): Int {
return major * minor * patch
}
companion object {
private fun doesContainsVersion(string: String): Boolean {
val versionArray = string.split(".")
return versionArray.size in 2..3
&& versionArray[0].toIntOrNull() != null
&& versionArray[1].toIntOrNull() != null
&& (versionArray.size == 2 || versionArray[2].toIntOrNull() != null)
}
fun from(string: String): Version? {
return if (doesContainsVersion(string)) {
Version(string)
} else {
null
}
}
}
}
用法:
val version1 = Version.from("3.2")
val version2 = Version.from("3.2.1")
version1 <= version2
此代码尝试解决这种类型的比较版本。
大多数版本说明符，如>= 1.0，都是不言自明的。的 说明符~>具有特殊含义，最好通过示例来说明。~> 2.0.3是 与>= 2.0.3和< 2.1相同。~> 2.1与>= 2.1相同，且< 3.0.
public static boolean apply(String cmpDeviceVersion, String reqDeviceVersion)
{
Boolean equal = !cmpDeviceVersion.contains(">") && !cmpDeviceVersion.contains(">=") &&
!cmpDeviceVersion.contains("<") && !cmpDeviceVersion.contains("<=") &&
!cmpDeviceVersion.contains("~>");
Boolean between = cmpDeviceVersion.contains("~>");
Boolean higher = cmpDeviceVersion.contains(">") && !cmpDeviceVersion.contains(">=") && !cmpDeviceVersion.contains("~>");
Boolean higherOrEqual = cmpDeviceVersion.contains(">=");
Boolean less = cmpDeviceVersion.contains("<") && !cmpDeviceVersion.contains("<=");
Boolean lessOrEqual = cmpDeviceVersion.contains("<=");
cmpDeviceVersion = cmpDeviceVersion.replaceAll("[<>=~]", "");
cmpDeviceVersion = cmpDeviceVersion.trim();
String[] version = cmpDeviceVersion.split("\\.");
String[] reqVersion = reqDeviceVersion.split("\\.");
if(equal)
{
return isEqual(version, reqVersion);
}
else if(between)
{
return isBetween(version, reqVersion);
}
else if(higher)
{
return isHigher(version, reqVersion);
}
else if(higherOrEqual)
{
return isEqual(version, reqVersion) || isHigher(version, reqVersion);
}
else if(less)
{
return isLess(version, reqVersion);
}
else if(lessOrEqual)
{
return isEqual(version, reqVersion) || isLess(version, reqVersion);
}
return false;
}
private static boolean isEqual(String[] version, String[] reqVersion)
{
String strVersion = StringUtils.join(version);
String strReqVersion = StringUtils.join(reqVersion);
if(version.length > reqVersion.length)
{
Integer diff = version.length - reqVersion.length;
strReqVersion += StringUtils.repeat(".0", diff);
}
else if(reqVersion.length > version.length)
{
Integer diff = reqVersion.length - version.length;
strVersion += StringUtils.repeat(".0", diff);
}
return strVersion.equals(strReqVersion);
}
private static boolean isHigher(String[] version, String[] reqVersion)
{
String strVersion = StringUtils.join(version);
String strReqVersion = StringUtils.join(reqVersion);
if(version.length > reqVersion.length)
{
Integer diff = version.length - reqVersion.length;
strReqVersion += StringUtils.repeat(".0", diff);
}
else if(reqVersion.length > version.length)
{
Integer diff = reqVersion.length - version.length;
strVersion += StringUtils.repeat(".0", diff);
}
return strReqVersion.compareTo(strVersion) > 0;
}
private static boolean isLess(String[] version, String[] reqVersion)
{
String strVersion = StringUtils.join(version);
String strReqVersion = StringUtils.join(reqVersion);
if(version.length > reqVersion.length)
{
Integer diff = version.length - reqVersion.length;
strReqVersion += StringUtils.repeat(".0", diff);
}
else if(reqVersion.length > version.length)
{
Integer diff = reqVersion.length - version.length;
strVersion += StringUtils.repeat(".0", diff);
}
return strReqVersion.compareTo(strVersion) < 0;
}
private static boolean isBetween(String[] version, String[] reqVersion)
{
return (isEqual(version, reqVersion) || isHigher(version, reqVersion)) &&
isLess(getNextVersion(version), reqVersion);
}
private static String[] getNextVersion(String[] version)
{
String[] nextVersion = new String[version.length];
for(int i = version.length - 1; i >= 0 ; i--)
{
if(i == version.length - 1)
{
nextVersion[i] = "0";
}
else if((i == version.length - 2) && NumberUtils.isNumber(version[i]))
{
nextVersion[i] = String.valueOf(NumberUtils.toInt(version[i]) + 1);
}
else
{
nextVersion[i] = version[i];
}
}
return nextVersion;
}
想知道为什么每个人都假设版本只由整数组成-在我的情况下，它不是。
为什么要重新发明轮子(假设版本遵循Semver标准)
首先通过Maven安装https://github.com/vdurmont/semver4j
然后使用这个库
Semver sem = new Semver("1.2.3");
sem.isGreaterThan("1.2.2"); // true
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