Lar*_*rry 365 java string enums
使用存储在Enum中的值作为字符串文字的最佳方法是什么？例如:
public enum Modes {
some-really-long-string,
mode1,
mode2,
mode3
}
然后我可以用它Mode.mode1来返回它的字符串表示mode1.无需继续通话Mode.mode1.toString().
Mic*_*Lee 618
你不能.我想你在这里有四个选择.这四种方案都提供了解决方案,但方法略有不同......
选项一: 在name()枚举上使用内置.如果您不需要任何特殊的命名格式,这非常好.
String name = Modes.mode1.name(); // Returns the name of this enum constant, exactly as declared in its enum declaration.
选项二: 如果您想要更多控制,请为您的枚举添加覆盖属性
public enum Modes {
mode1 ("Fancy Mode 1"),
mode2 ("Fancy Mode 2"),
mode3 ("Fancy Mode 3");
private final String name;
private Modes(String s) {
name = s;
}
public boolean equalsName(String otherName) {
// (otherName == null) check is not needed because name.equals(null) returns false
return name.equals(otherName);
}
public String toString() {
return this.name;
}
}
选项三: 使用静态决赛而不是枚举:
public final class Modes {
public static final String MODE_1 = "Fancy Mode 1";
public static final String MODE_2 = "Fancy Mode 2";
public static final String MODE_3 = "Fancy Mode 3";
private Modes() { }
}
选项四: 接口包含public,static和final的每个字段:
public interface Modes {
String MODE_1 = "Fancy Mode 1";
String MODE_2 = "Fancy Mode 2";
String MODE_3 = "Fancy Mode 3";
}
Rya*_*art 469
每个枚举都有name()和valueOf(String)方法.前者返回枚举的字符串名称,后者给出名称为字符串的枚举值.这就像你在寻找什么？
String name = Modes.mode1.name();
Modes mode = Modes.valueOf(name);
Enum本身也有一个静态valueOf(Class,String),所以你也可以使用
Modes mode = Enum.valueOf(Modes.class, name);
Ben*_*uer 75
您可以toString()为每个枚举值覆盖该方法.
例:
public enum Country {
DE {
@Override
public String toString() {
return "Germany";
}
},
IT {
@Override
public String toString() {
return "Italy";
}
},
US {
@Override
public String toString() {
return "United States";
}
}
}
用法:
public static void main(String[] args) {
System.out.println(Country.DE); // Germany
System.out.println(Country.IT); // Italy
System.out.println(Country.US); // United States
}
ibe*_*dev 32
正如Benny Neugebauer所提到的,你可以覆盖toString().但是,相反,为每个枚举字段覆盖toString,我更喜欢这样的东西:
public enum Country{
SPAIN("España"),
ITALY("Italia"),
PORTUGAL("Portugal");
private String value;
Country(final String value) {
this.value = value;
}
public String getValue() {
return value;
}
@Override
public String toString() {
return this.getValue();
}
}
您还可以添加静态方法来检索所有字段,打印所有字段等.只需调用getValue以获取与每个枚举项关联的字符串
小智 20
public enum Modes {
MODE1("Mode1"),
MODE2("Mode2"),
MODE3("Mode3");
private String value;
public String getValue() {
return value;
}
private Modes(String value) {
this.value = value;
}
}
您可以在下面的任何地方拨打电话,以便从枚举中获取值作为字符串.
Modes.MODE1.getvalue();
这将返回"Mode1"作为字符串.
您可以使用,Mode.mode1.name()但通常不需要这样做.
Mode mode =
System.out.println("The mode is "+mode);
据我所知,获得这个名字的唯一方法就是
Mode.mode1.name();
但是,如果你真的需要这种方式,你可以这样做:
public enum Modes {
mode1 ("Mode1"),
mode2 ("Mode2"),
mode3 ("Mode3");
private String name;
private Modes(String s) {
name = s;
}
}
对于我的枚举,我真的不想将它们分配给每个1个字符串.这是我在枚举上实现toString()方法的方法.
enum Animal
{
DOG, CAT, BIRD;
public String toString(){
switch (this) {
case DOG: return "Dog";
case CAT: return "Cat";
case BIRD: return "Bird";
}
return null;
}
}
我对你的问题的解决方案！
import java.util.HashMap;
import java.util.Map;
public enum MapEnumSample {
Mustang("One of the fastest cars in the world!"),
Mercedes("One of the most beautiful cars in the world!"),
Ferrari("Ferrari or Mercedes, which one is the best?");
private final String description;
private static Map<String, String> enumMap;
private MapEnumSample(String description) {
this.description = description;
}
public String getEnumValue() {
return description;
}
public static String getEnumKey(String name) {
if (enumMap == null) {
initializeMap();
}
return enumMap.get(name);
}
private static Map<String, String> initializeMap() {
enumMap = new HashMap<String, String>();
for (MapEnumSample access : MapEnumSample.values()) {
enumMap.put(access.getEnumValue(), access.toString());
}
return enumMap;
}
public static void main(String[] args) {
// getting value from Description
System.out.println(MapEnumSample.getEnumKey("One of the fastest cars in the world!"));
// getting value from Constant
System.out.println(MapEnumSample.Mustang.getEnumValue());
System.out.println(MapEnumSample.getEnumKey("One of the most beautiful cars in the world!"));
System.out.println(MapEnumSample.Mercedes.getEnumValue());
// doesnt exist in Enum
System.out.println("Mustang or Mercedes, which one is the best?");
System.out.println(MapEnumSample.getEnumKey("Mustang or Mercedes, which one is the best?") == null ? "I don't know!" : "I believe that "
+ MapEnumSample.getEnumKey("Ferrari or Mustang, which one is the best?") + " is the best!.");
// exists in Enum
System.out.println("Ferrari or Mercedes, wich one is the best?");
System.out.println(MapEnumSample.getEnumKey("Ferrari or Mercedes, which one is the best?") == null ? "I don't know!" : "I believe that "
+ MapEnumSample.getEnumKey("Ferrari or Mercedes, which one is the best?") + " is the best!");
}
}
小智 5
public enum Environment
{
PROD("https://prod.domain.com:1088/"),
SIT("https://sit.domain.com:2019/"),
CIT("https://cit.domain.com:8080/"),
DEV("https://dev.domain.com:21323/");
private String url;
Environment(String envUrl) {
this.url = envUrl;
}
public String getUrl() {
return url;
}
}
String prodUrl = Environment.PROD.getUrl();
它将打印：
https://prod.domain.com:1088/
这种枚举字符串常量的设计适用于大多数情况。