java - 请教前辈们关于枚举值如何一对多关联额？

Answer 1

Use enumeration? ? If the business is simple, it is recommended to use map to construct the index yourself. If the business is complex, you can use a graph database such as neo4j

Answer 2

Java’s enumeration is not only a simple function, but also very scalable. According to your requirements, write an example for you to see:

enum Country {
    CN ("北京", "上海", "广州", "深圳"),
    US ("华盛顿", "洛杉矶")
    ;
    public final String[] cities;
    
    public Country(String... cities) {
        this.cities = cities;
    }
}

Answer 3

In C language, for example, use 16-bit unsigned int to represent
0xabcd. The first two digits represent the country and the last two digits are the city. Do bit operations
0x0100 ~ 0x01ff China
0x0200 ~ 0x02ff United States