javaconstant类_创建java常量类⾸先看⽰例：
/**
* Method One
*/
interface ConstantInterface {
String SUNDAY = "SUNDAY";
String MONDAY = "MONDAY";
String TUESDAY = "TUESDAY";
String WEDNESDAY = "WEDNESDAY";
String THURSDAY = "THURSDAY";
String FRIDAY = "FRIDAY";
String SATURDAY = "SATURDAY";
}
/**
* Method Two
*/
enum ConstantEnum {
SUNDAY, MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY, SATURDAY
}
/**
* Method Three
*/
class ConstantClassField {
public static final String SUNDAY = "SUNDAY";
public static final String MONDAY = "MONDAY";
public static final String TUESDAY = "TUESDAY";
初代吸血鬼第二季15public static final String WEDNESDAY = "WEDNESDAY";
public static final String THURSDAY = "THURSDAY";
引文翻译public static final String FRIDAY = "FRIDAY";
public static final String SATURDAY = "SATURDAY";
}
/**
* Method Four
* /developerworks/cn/java/l-java-interface/index.html */
class ConstantClassFunction {
private static final String SUNDAY = "SUNDAY";
private static final String MONDAY = "MONDAY";
private static final String TUESDAY = "TUESDAY";
private static final String WEDNESDAY = "WEDNESDAY";
society是什么意思private static final String THURSDAY = "THURSDAY";
private static final String FRIDAY = "FRIDAY";
private static final String SATURDAY = "SATURDAY";lovett
public static String getSunday() {
return SUNDAY;
csharp
}
public static String getMonday() {
return MONDAY;
}
public static String getTuesday() {
return TUESDAY;
}
public static String getWednesday() {
return WEDNESDAY;
}
public static String getThursday() {
return THURSDAY;
}
public static String getFirday() {
return FRIDAY;
}
public static String getSaturday() {
return SATURDAY;
}
}
public class TestConstant {
美国留学一年费用static final String day = "saturday";
public static void main(String[] args) {
System.out.println("Is today Saturday?");
System.out.println(day.equalsIgnoreCa(ConstantInterface.SATURDAY)); System.out.println(day.equalsIgnoreCa(ConstantEnum.SATURDAY.name())); System.out.println(day.equalsIgnoreCa(ConstantClassField.SATURDAY)); System.out.println(day.equalsIgnoreCa(ConstantClassFunction
.getSaturday()));
}
}
/**
* Method One
*/
interface ConstantInterface {
String SUNDAY = "SUNDAY";
String MONDAY = "MONDAY";
String TUESDAY = "TUESDAY";
String WEDNESDAY = "WEDNESDAY";
String THURSDAY = "THURSDAY";
String FRIDAY = "FRIDAY";
String SATURDAY = "SATURDAY";
}
/**
* Method Two
*/
enum ConstantEnum {
SUNDAY, MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY, SATURDAY }
/**
* Method Three
*/
class ConstantClassField {
public static final String SUNDAY = "SUNDAY";
public static final String MONDAY = "MONDAY";
public static final String TUESDAY = "TUESDAY";
public static final String WEDNESDAY = "WEDNESDAY";
public static final String THURSDAY = "THURSDAY";
public static final String FRIDAY = "FRIDAY";
public static final String SATURDAY = "SATURDAY";
esm是什么}
/**
* Method Four
* /developerworks/cn/java/l-java-interface/index.html */c语言学习班
class ConstantClassFunction {
private static final String SUNDAY = "SUNDAY";
private static final String MONDAY = "MONDAY";
private static final String TUESDAY = "TUESDAY";
private static final String WEDNESDAY = "WEDNESDAY";
private static final String THURSDAY = "THURSDAY";
private static final String FRIDAY = "FRIDAY";
private static final String SATURDAY = "SATURDAY";
public static String getSunday() {
return SUNDAY;
}
public static String getMonday() {
return MONDAY;
}
public static String getTuesday() {
return TUESDAY;
}
public static String getWednesday() {
return WEDNESDAY;
}
public static String getThursday() {
return THURSDAY;
}
public static String getFirday() {
return FRIDAY;
}
public static String getSaturday() {
return SATURDAY;
}
}
public class TestConstant {
static final String day = "saturday";
public static void main(String[] args) {
System.out.println("Is today Saturday?");
System.out.println(day.equalsIgnoreCa(ConstantInterface.SATURDAY));
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System.out.println(day.equalsIgnoreCa(ConstantEnum.SATURDAY.name()));
System.out.println(day.equalsIgnoreCa(ConstantClassField.SATURDAY));
System.out.println(day.equalsIgnoreCa(ConstantClassFunction
.getSaturday()));
}
}
⽅法⼀采⽤接⼝(Interface)的中变量默认为static final的特性。
⽅法⼆采⽤了Java 5.0中引⼊的Enum类型。
⽅法三采⽤了在普通类中使⽤static final修饰变量的⽅法。
⽅法四类似⽅法三，但是通过函数来获取常量。frogen
⾸先定义全局变量似乎有违Java的⾯向对象的封装特性，增加的耦合。所以最佳的⽅法是避免定义全局变量。如果是参数等，可以写⼊配置⽂件。如果实在是必须的，⽅法⼆是最为推荐的。⽅法三是⼤家都能想到的，⾮常的直观。⽅法⼀和⽅法三本质上⼀样。⽅法四提供了灵活性，具体参考引⽤【1】。
