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();

}

*/