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

您需要规范化版本字符串,以便对它们进行比较。类似的

import java.util.regex.Pattern;

public class Main {
    public static void main(String... args) {
        compare("1.0", "1.1");
        compare("1.0.1", "1.1");
        compare("1.9", "1.10");
        compare("1.a", "1.9");
    }

    private static void compare(String v1, String v2) {
        String s1 = normalisedVersion(v1);
        String s2 = normalisedVersion(v2);
        int cmp = s1.compareTo(s2);
        String cmpStr = cmp < 0 ? "<" : cmp > 0 ? ">" : "==";
        System.out.printf("'%s' %s '%s'%n", v1, cmpStr, v2);
    }

    public static String normalisedVersion(String version) {
        return normalisedVersion(version, ".", 4);
    }

    public static String normalisedVersion(String version, String sep, int maxWidth) {
        String[] split = Pattern.compile(sep, Pattern.LITERAL).split(version);
        StringBuilder sb = new StringBuilder();
        for (String s : split) {
            sb.append(String.format("%" + maxWidth + 's', s));
        }
        return sb.toString();
    }
}

打印

'1.0' < '1.1' '1.0.1' < '1.1' '1.9' < '1.10' “1。A ' > '1.9'

其他回答

// VersionComparator.java
import java.util.Comparator;

public class VersionComparator implements Comparator {

    public boolean equals(Object o1, Object o2) {
        return compare(o1, o2) == 0;
    }

    public int compare(Object o1, Object o2) {
        String version1 = (String) o1;
        String version2 = (String) o2;

        VersionTokenizer tokenizer1 = new VersionTokenizer(version1);
        VersionTokenizer tokenizer2 = new VersionTokenizer(version2);

        int number1 = 0, number2 = 0;
        String suffix1 = "", suffix2 = "";

        while (tokenizer1.MoveNext()) {
            if (!tokenizer2.MoveNext()) {
                do {
                    number1 = tokenizer1.getNumber();
                    suffix1 = tokenizer1.getSuffix();
                    if (number1 != 0 || suffix1.length() != 0) {
                        // Version one is longer than number two, and non-zero
                        return 1;
                    }
                }
                while (tokenizer1.MoveNext());

                // Version one is longer than version two, but zero
                return 0;
            }

            number1 = tokenizer1.getNumber();
            suffix1 = tokenizer1.getSuffix();
            number2 = tokenizer2.getNumber();
            suffix2 = tokenizer2.getSuffix();

            if (number1 < number2) {
                // Number one is less than number two
                return -1;
            }
            if (number1 > number2) {
                // Number one is greater than number two
                return 1;
            }

            boolean empty1 = suffix1.length() == 0;
            boolean empty2 = suffix2.length() == 0;

            if (empty1 && empty2) continue; // No suffixes
            if (empty1) return 1; // First suffix is empty (1.2 > 1.2b)
            if (empty2) return -1; // Second suffix is empty (1.2a < 1.2)

            // Lexical comparison of suffixes
            int result = suffix1.compareTo(suffix2);
            if (result != 0) return result;

        }
        if (tokenizer2.MoveNext()) {
            do {
                number2 = tokenizer2.getNumber();
                suffix2 = tokenizer2.getSuffix();
                if (number2 != 0 || suffix2.length() != 0) {
                    // Version one is longer than version two, and non-zero
                    return -1;
                }
            }
            while (tokenizer2.MoveNext());

            // Version two is longer than version one, but zero
            return 0;
        }
        return 0;
    }
}

// VersionTokenizer.java
public class VersionTokenizer {
    private final String _versionString;
    private final int _length;

    private int _position;
    private int _number;
    private String _suffix;
    private boolean _hasValue;

    public int getNumber() {
        return _number;
    }

    public String getSuffix() {
        return _suffix;
    }

    public boolean hasValue() {
        return _hasValue;
    }

    public VersionTokenizer(String versionString) {
        if (versionString == null)
            throw new IllegalArgumentException("versionString is null");

        _versionString = versionString;
        _length = versionString.length();
    }

    public boolean MoveNext() {
        _number = 0;
        _suffix = "";
        _hasValue = false;

        // No more characters
        if (_position >= _length)
            return false;

        _hasValue = true;

        while (_position < _length) {
            char c = _versionString.charAt(_position);
            if (c < '0' || c > '9') break;
            _number = _number * 10 + (c - '0');
            _position++;
        }

        int suffixStart = _position;

        while (_position < _length) {
            char c = _versionString.charAt(_position);
            if (c == '.') break;
            _position++;
        }

        _suffix = _versionString.substring(suffixStart, _position);

        if (_position < _length) _position++;

        return true;
    }
}

例子:

public class Main
{
    private static VersionComparator cmp;

    public static void main (String[] args)
    {
        cmp = new VersionComparator();
        Test(new String[]{"1.1.2", "1.2", "1.2.0", "1.2.1", "1.12"});
        Test(new String[]{"1.3", "1.3a", "1.3b", "1.3-SNAPSHOT"});
    }

    private static void Test(String[] versions) {
        for (int i = 0; i < versions.length; i++) {
            for (int j = i; j < versions.length; j++) {
                Test(versions[i], versions[j]);
            }
        }
    }

    private static void Test(String v1, String v2) {
        int result = cmp.compare(v1, v2);
        String op = "==";
        if (result < 0) op = "<";
        if (result > 0) op = ">";
        System.out.printf("%s %s %s\n", v1, op, v2);
    }
}

输出:

1.1.2 == 1.1.2                --->  same length and value
1.1.2 < 1.2                   --->  first number (1) less than second number (2) => -1
1.1.2 < 1.2.0                 --->  first number (1) less than second number (2) => -1
1.1.2 < 1.2.1                 --->  first number (1) less than second number (2) => -1
1.1.2 < 1.12                  --->  first number (1) less than second number (12) => -1
1.2 == 1.2                    --->  same length and value
1.2 == 1.2.0                  --->  first shorter than second, but zero
1.2 < 1.2.1                   --->  first shorter than second, and non-zero
1.2 < 1.12                    --->  first number (2) less than second number (12) => -1
1.2.0 == 1.2.0                --->  same length and value
1.2.0 < 1.2.1                 --->  first number (0) less than second number (1) => -1
1.2.0 < 1.12                  --->  first number (2) less than second number (12) => -1
1.2.1 == 1.2.1                --->  same length and value
1.2.1 < 1.12                  --->  first number (2) less than second number (12) => -1
1.12 == 1.12                  --->  same length and value

1.3 == 1.3                    --->  same length and value
1.3 > 1.3a                    --->  first suffix ('') is empty, but not second ('a') => 1
1.3 > 1.3b                    --->  first suffix ('') is empty, but not second ('b') => 1
1.3 > 1.3-SNAPSHOT            --->  first suffix ('') is empty, but not second ('-SNAPSHOT') => 1
1.3a == 1.3a                  --->  same length and value
1.3a < 1.3b                   --->  first suffix ('a') compared to second suffix ('b') => -1
1.3a < 1.3-SNAPSHOT           --->  first suffix ('a') compared to second suffix ('-SNAPSHOT') => -1
1.3b == 1.3b                  --->  same length and value
1.3b < 1.3-SNAPSHOT           --->  first suffix ('b') compared to second suffix ('-SNAPSHOT') => -1
1.3-SNAPSHOT == 1.3-SNAPSHOT  --->  same length and value

我写了一个名为MgntUtils的开源库,它有一个用于字符串版本的实用程序。它正确地比较它们,适用于版本范围等等。下面是这个库javadoc参见方法TextUtils.comapreVersions(…)它已经被大量使用并经过了良好的测试。下面这篇文章描述了这个库以及如何获取它。它可以作为Maven工件和在github上获得(包括源代码和JavaDoc)

public static void main(String[] args) {

    String version1 = "1.0";
    String version2 = "1.0.0";
    String[] version1_splits = version1.split("\\.");
    String[] version2_splits = version2.split("\\.");
    int length = version1_splits.length >= version2_splits.length ? version1_splits.length : version2_splits.length;
    int i=0;
    for(;i<length;i++){
        int version1_int = getValue(version1_splits,i);
        int version2_int = getValue(version2_splits,i);
        if(version1_int > version2_int){
            System.out.println("version1 > version2");
            break;
        }
        else if(version1_int < version2_int){
            System.out.println("version2 > version1");
            break;
        }
        else{
            if(i == length-1)
            System.out.println("version1 = version2");
        }
    }
}

private static int getValue(String[] version1_splits, int i) {
    int temp;
    try{
        temp = Integer.valueOf(version1_splits[i]);
    }
    catch(IndexOutOfBoundsException e){
        temp=0;
    }

    return temp;
}

由于本页上没有答案能很好地处理混合文本,我做了自己的版本:

import java.util.regex.Matcher;
import java.util.regex.Pattern;

class Main {
    static double parseVersion(String v) {
        if (v.isEmpty()) {
            return 0;
        }
        Pattern p = Pattern.compile("^(\\D*)(\\d*)(\\D*)$");
        Matcher m = p.matcher(v);
        m.find();
        if (m.group(2).isEmpty()) {
            // v1.0.0.[preview]
            return -1;
        }
        double i = Integer.parseInt(m.group(2));
        if (!m.group(3).isEmpty()) {
            // v1.0.[0b]
            i -= 0.1;
        }
        return i;
    }

    public static int versionCompare(String str1, String str2) {
        String[] v1 = str1.split("\\.");
        String[] v2 = str2.split("\\.");
        int i = 0;
        for (; i < v1.length && i < v2.length; i++) {
            double iv1 = parseVersion(v1[i]);
            double iv2 = parseVersion(v2[i]);

            if (iv1 != iv2) {
                return iv1 - iv2 < 0 ? -1 : 1;
            }
        }
        if (i < v1.length) {
            // "1.0.1", "1.0"
            double iv1 = parseVersion(v1[i]);
            return iv1 < 0 ? -1 : (int) Math.ceil(iv1);
        }
        if (i < v2.length) {
            double iv2 = parseVersion(v2[i]);
            return -iv2 < 0 ? -1 : (int) Math.ceil(iv2);
        }
        return 0;
    }


    public static void main(String[] args) {
        System.out.println("versionCompare(v1.0.0, 1.0.0)");
        System.out.println(versionCompare("v1.0.0", "1.0.0")); // 0

        System.out.println("versionCompare(v1.0.0b, 1.0.0)");
        System.out.println(versionCompare("v1.0.0b", "1.0.0")); // -1

        System.out.println("versionCompare(v1.0.0.preview, 1.0.0)");
        System.out.println(versionCompare("v1.0.0.preview", "1.0.0")); // -1

        System.out.println("versionCompare(v1.0, 1.0.0)");
        System.out.println(versionCompare("v1.0", "1.0.0")); // 0

        System.out.println("versionCompare(ver1.0, 1.0.1)");
        System.out.println(versionCompare("ver1.0", "1.0.1")); // -1
    }
}

不过,在需要比较“alpha”和“beta”的情况下,它仍然不够。

基于https://stackoverflow.com/a/27891752/2642478

class Version(private val value: String) : Comparable<Version> {
    private val splitted by lazy { value.split("-").first().split(".").map { it.toIntOrNull() ?: 0 } }

    override fun compareTo(other: Version): Int {
        for (i in 0 until maxOf(splitted.size, other.splitted.size)) {
            val compare = splitted.getOrElse(i) { 0 }.compareTo(other.splitted.getOrElse(i) { 0 })
            if (compare != 0)
                return compare
        }
        return 0
    }
}

你可以用like:

    System.err.println(Version("1.0").compareTo( Version("1.0")))
    System.err.println(Version("1.0") < Version("1.1"))
    System.err.println(Version("1.10") > Version("1.9"))
    System.err.println(Version("1.10.1") > Version("1.10"))
    System.err.println(Version("0.0.1") < Version("1"))