1.枚舉類入門
Java枚舉類是從Java5開始支持的。
枚舉類的構造方法是用private修飾的。枚舉類的所有實例必須在類的第一行列出，否則這個枚舉類不會產生對象。
而且這些實例都是public static void.
每個枚舉類都有一個values方法，該方法可以遍歷枚舉類的所有實例
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public class Test {
public static void tell(Season s)
{
switch(s)
{
case Spring:
System.out.println(s+"春天");
break;
case Summer:System.out.println(s+"夏天");
break;
case Fall:System.out.println(s+"秋天");
break;
case Winter:System.out.println(s+"冬天");
break;
}
}
public static void main(String[] args) {
for(Season s:Season.values())
{
System.out.println(s);
}
tell(Season.Fall);
}
}
enum Season
{
Spring,Summer,Fall,Winter;
}
public class Test {
public static void tell(Season s)
{
switch(s)
{
case Spring:
System.out.println(s+"春天");
break;
case Summer:System.out.println(s+"夏天");
break;
case Fall:System.out.println(s+"秋天");
break;
case Winter:System.out.println(s+"冬天");
break;
}
}
public static void main(String[] args) {
for(Season s:Season.values())
{
System.out.println(s);
}
tell(Season.Fall);
}
}
enum Season
{
Spring,Summer,Fall,Winter;
}
2.枚舉類的構造方法和對象
枚舉類的構造方法是private，所以不能使用new創建對象
可以使用Enum.valueOf(Class c,String s);創建對象
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public class Test {
public static void main(String[] args) {
Season s=Enum.valueOf(Season.class, "Summer");
System.out.println(s);
}
}
enum Season
{
Spring,Summer,Fall,Winter;
}
public class Test {
public static void main(String[] args) {
Season s=Enum.valueOf(Season.class, "Summer");
System.out.println(s);
}
}
enum Season
{
Spring,Summer,Fall,Winter;
}一旦爲枚舉類定義了帶參數的構造方法後，列舉枚舉類就必須對應的傳入參數
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public class Test {
public static void main(String[] args) {
Season s=Enum.valueOf(Season.class, "Summer");
System.out.println(s.name);
}
}
enum Season
{
Spring("春天"),Summer("夏天"),Fall("秋天"),Winter("冬天");
public String name;
private Season(String name)
{
this.name=name;
}
}
public class Test {
public static void main(String[] args) {
Season s=Enum.valueOf(Season.class, "Summer");
System.out.println(s.name);
}
}
enum Season
{
Spring("春天"),Summer("夏天"),Fall("秋天"),Winter("冬天");
public String name;
private Season(String name)
{
this.name=name;
}
}3.枚舉類實現接口
與普通類一樣，枚舉類實現接口，則必須實現接口中所有的方法
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public class Test {
public static void main(String[] args) {
Season s=Enum.valueOf(Season.class, "Summer");
System.out.println(s.name);
s.printInfo();
}
}
enum Season implements Infomation
{
Spring("春天"),Summer("夏天"),Fall("秋天"),Winter("冬天");
public String name;
private Season(String name)
{
this.name=name;
}
@Override
public void printInfo() {
System.out.println(name);
}
}
interface Infomation
{
void printInfo();
}
public class Test {
public static void main(String[] args) {
Season s=Enum.valueOf(Season.class, "Summer");
System.out.println(s.name);
s.printInfo();
}
}
enum Season implements Infomation
{
Spring("春天"),Summer("夏天"),Fall("秋天"),Winter("冬天");
public String name;
private Season(String name)
{
this.name=name;
}
@Override
public void printInfo() {
System.out.println(name);
}
}
interface Infomation
{
void printInfo();
}
也可以使用匿名內部類的方法爲每一個枚舉類對象實現接口
[java] view plaincopyprint?
public class Test {
public static void main(String[] args) {
Season s=Enum.valueOf(Season.class, "Summer");
System.out.println(s.name);
s.printInfo();
}
}
enum Season implements Infomation
{
Spring("春天"){
@Override
public void printInfo() {
// TODO Auto-generated method stub
System.out.println("春天溫暖");
}
},Summer("夏天")
{
@Override
public void printInfo() {
// TODO Auto-generated method stub
System.out.println("夏天炎熱");
}
},Fall("秋天")
{
@Override
public void printInfo() {
// TODO Auto-generated method stub
System.out.println("秋天涼爽");
}
},Winter("冬天"){
@Override
public void printInfo() {
// TODO Auto-generated method stub
System.out.println("冬天寒冷");
}
};
public String name;
private Season(String name)
{
this.name=name;
}
}
interface Infomation
{
void printInfo();
}
public class Test {
public static void main(String[] args) {
Season s=Enum.valueOf(Season.class, "Summer");
System.out.println(s.name);
s.printInfo();
}
}
enum Season implements Infomation
{
Spring("春天"){
@Override
public void printInfo() {
// TODO Auto-generated method stub
System.out.println("春天溫暖");
}
},Summer("夏天")
{
@Override
public void printInfo() {
// TODO Auto-generated method stub
System.out.println("夏天炎熱");
}
},Fall("秋天")
{
@Override
public void printInfo() {
// TODO Auto-generated method stub
System.out.println("秋天涼爽");
}
},Winter("冬天"){
@Override
public void printInfo() {
// TODO Auto-generated method stub
System.out.println("冬天寒冷");
}
};
public String name;
private Season(String name)
{
this.name=name;
}
}
interface Infomation
{
void printInfo();
}
4.包含抽象方法的枚舉類
包含抽象方法枚舉類，要實例化對象的話，就得讓每個對象實現抽象方法
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public class Test {
public static void main(String[] args) {
Season s=Enum.valueOf(Season.class, "Summer");
System.out.println(s.name);
s.printInfo();
s.whatToDo();
}
}
enum Season implements Infomation
{
Spring("春天"){
@Override
public void printInfo() {
// TODO Auto-generated method stub
System.out.println("春天溫暖");
}
@Override
public void whatToDo() {
// TODO Auto-generated method stub
System.out.println("我去春遊");
}
},Summer("夏天")
{
@Override
public void printInfo() {
// TODO Auto-generated method stub
System.out.println("夏天炎熱");
}
@Override
public void whatToDo() {
// TODO Auto-generated method stub
System.out.println("我去游泳");
}
},Fall("秋天")
{
@Override
public void printInfo() {
// TODO Auto-generated method stub
System.out.println("秋天涼爽");
}
@Override
public void whatToDo() {
// TODO Auto-generated method stub
System.out.println("我去玩乒乓球");
}
},Winter("冬天"){
@Override
public void printInfo() {
// TODO Auto-generated method stub
System.out.println("冬天寒冷");
}
@Override
public void whatToDo() {
// TODO Auto-generated method stub
System.out.println("我去賞雪觀梅");
}
};
public String name;
private Season(String name)
{
this.name=name;
}
public abstract void whatToDo();
}
interface Infomation
{
void printInfo();
}