The difference between static constants and enumeration classes in Java

In projects we sometimes use constants, static constants and enumerations, so what are the differences between them? Let’s look at a few examples first:

According to the constants used in the framework:

    /** 正常状态 */
    public static final String NORMAL = "0";

    /** 异常状态 */
    public static final String EXCEPTION = "1";

    /** 用户封禁状态 */
    public static final String USER_DISABLE = "1";

    /** 角色封禁状态 */
    public static final String ROLE_DISABLE = "1";

    /** 部门正常状态 */
    public static final String DEPT_NORMAL = "0";

    /** 部门停用状态 */
    public static final String DEPT_DISABLE = "1";

    /** 字典正常状态 */
    public static final String DICT_NORMAL = "0";

If based on the enumeration used in the framework:

public enum UserStatus
{
    OK("0", "正常"), DISABLE("1", "停用"), DELETED("2", "删除");

    private final String code;
    private final String info;

    UserStatus(String code, String info)
    {
        this.code = code;
        this.info = info;
    }

    public String getCode()
    {
        return code;
    }

    public String getInfo()
    {
        return info;
    }
}

Constants: In Java, constants are declared using the keyword final. final means that this variable can only be assigned once. Once assigned a value, it cannot be changed.

Static constant: If you use static modification when defining a constant, then this constant is called a static constant. If you add public, then this constant can also be used in other classes.

Enumeration class: All enumeration types are subclasses of the Enum class. Enumerations are usually a group of instances that describe the same characteristics.

From the above definitions and examples it can be concluded that:

A single fixed value is usually represented by a constant; static constants can use public to modify the scope;

A set of values ​​describing the same field is usually represented using an enumeration; an enumeration can initialize an instance.