枚举类型的总结

package EnumExercise;
 
public class Student {
private String name;
private Grade grade;
public Student(String name, Grade grade) {
super();
this.name = name;
this.grade = grade;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Grade getGrade() {
return grade;
}
public void setGrade(Grade grade) {
this.grade = grade;
}
public static void main(String[] args) {
Student s=new Student("hu",Grade.A);
String grade="A";
//将一个字符串转换为对应的枚举 对象
Grade  g=Grade.valueOf(Grade.class, grade);
System.out.println(g.toString());
//获取 枚举的类型的所有枚举 对象
Grade  gs[]=Grade.values();
for(Grade tempG:gs){
System.out.println(tempG.toString());
}
}
}
/*JDK5之后开始使用枚举类型，其实现原理与之前相同，但是实现方便*/
enum Grade{//这是简单的枚举
A,B,C,D,E//枚举对象
}
enum Grade2{
A("100-90"),B("89-60"),C("59-40"),D("39-20"),E("20-0");//枚举对象
//枚举对象可以有属性
private String value;
private Grade2(String value){//枚举类型的构造函数必须是私有的
this.value=value;
}
 
public String getValue() {
return value;
}
}
//为枚举类型添加方法
enum Grade3{
A("100-90"){
public String toLocalString() {
// TODO Auto-generated method stub
return "优";
}
}
,B("89-60"){
public String toLocalString() {
// TODO Auto-generated method stub
return "良";
}
}
,C("59-40"){
public String toLocalString() {
// TODO Auto-generated method stub
return "差";
}
}
,D("39-20"){
public String toLocalString() {
// TODO Auto-generated method stub
return "很差";
}
}
,E("20-0"){
public String toLocalString() {
// TODO Auto-generated method stub
return "极其差";
}
};//枚举对象
//枚举对象可以有属性
private String value;
private Grade3(String value){//枚举类型的构造函数必须是私有的
this.value=value;
}
 
public String getValue() {
return value;
}
//定义一个抽象方法，然后在各自的实例对象中实现各自需要的方法
public abstract String toLocalString();
}
/*JDK5以前实现控制字段只能在固定范围之间取值的方法
class Grade {
private Grade(){
 
}
Grade A=new Grade();
Grade B=new Grade();
Grade C=new Grade();
Grade D=new Grade();
}
*/