用Jackson序列化枚举

public enum Color {
    RED, GREEN, BLUE
}

ObjectMapper objectMapper = new ObjectMapper();
Color color = Color.RED;
String jsonString = objectMapper.writeValueAsString(color);
System.out.println(jsonString); // 输出 "RED"

public enum Color {
    RED(0), GREEN(1), BLUE(2);

    private int value;

    Color(int value) {
        this.value = value;
    }

    @JsonValue
    public int getValue() {
        return value;
    }
}

ObjectMapper objectMapper = new ObjectMapper();
Color color = Color.RED;
String jsonString = objectMapper.writeValueAsString(color);
System.out.println(jsonString); // 输出 "0"