/**
 *  实现版本号比较
 * 支持任意数字字母版本号比较，这里实现的是用点号（.）作为分隔符
 * 支持任意长度的小版本号比较
 */
public static int compareVersion(String ver1, String ver2){
        if(ver1 == null && ver2 == null){
            throw new RuntimeException("版本号不能都为空");
        }
        
        if(ver1 == null){
            return -1;
        }
        
        if(ver2 == null){
            return 1;
        }
        
        if(ver1.equals(ver2)) {
            return 0;
        }

        String [] version1 = ver1.split("\\.");
        String [] version2 = ver2.split("\\.");
        
            
        String defValue = "0000000000";
        String format = "%" + defValue.length() + "s";
        StringBuilder ver1Builder = new StringBuilder(version1.length * 10);
        StringBuilder ver2Builder = new StringBuilder(version2.length * 10);
        
        if(version1.length > version2.length) {
            for (int i=0; i<version1.length ;i++ ) {
                ver1Builder.append(String.format(format, version1[i]).replace(' ', '0'));
                ver2Builder.append(version2.length > i? String.format(format, version2[i]).replace(' ', '0') : defValue);
            }
        
        } else if(version1.length < version2.length){
            for (int i=0; i<version2.length ;i++ ) {
                ver2Builder.append(String.format(format, version2[i]).replace(' ', '0'));
                ver1Builder.append(version1.length > i? String.format(format, version1[i]).replace(' ', '0') : defValue);
            }

        } else {
            for (int i=0; i<version2.length ;i++ ) {
                ver1Builder.append(String.format(format, version1[i]).replace(' ', '0'));
                ver2Builder.append(String.format(format, version2[i]).replace(' ', '0'));
            }
        }

        return ver1Builder.toString().compareTo(ver2Builder.toString());
    }

测试代码

compareVersion("1.2", "1.2.312.3") //返回<0的数字    

compareVersion("12", "1.2.M1") //返回>0的数字

compareVersion("1.2.3M", "1.2.3M") //返回0