[Java知识库]枚举类型与泛型的学习

interface Constants {
    public static final int Constants_A = 1;
    public static final int Constants_B = 12;

}

public class ConstantsTest {
    enum Constants2{
        Constants_A,Constants_B
    }
    public static void doit(int c){
        switch (c){
            case Constants.Constants_A:
                System.out.println("doit() Constants_A");
                break;
            case Constants.Constants_B:
                System.out.println("doit() COnstants_B");
                break;
        }
    }

    public static void doit2(Constants2 c){
        switch (c){
            case Constants_A:
                System.out.println("doit() Constants_A");
                break;
            case Constants_B:
                System.out.println("doit() COnstants_B");
                break;
        }
    }

    public static void compare(Constants2 c){
        for (int i = 0; i <Constants2.values().length ; i++) {
            System.out.println(c+"与"+Constants2.values()[i]+"的比较结果为："+c.compareTo(Constants2.values()[i]));
        }
    }

    public static void main(String[] args) {
        ConstantsTest.doit(Constants.Constants_A);
        ConstantsTest.doit2(Constants2.Constants_A);
        ConstantsTest.doit2(Constants2.Constants_B);
        ConstantsTest.doit(3);

        for (int i = 0; i <Constants2.values().length ; i++) {
            System.out.println("枚举类型成员变量:"+Constants2.values()[i]);
        }
        compare(Constants2.valueOf("Constants_B"));
    }

}

public class EnumIndexTest {
    enum Constants2{
        Constants_A("I am enum A"),
        Constants_B("I am enum B"),
        Constants_C("I am enum C"),
        Constants_D(3);
        private String description;
        private int i = 4;
        private Constants2(){}
        private Constants2(String description){
            this.description = description;
        }
        private Constants2(int i){
            this.i = this.i+i;
        }
        public String getDescription(){
            return description;
        }
        public int getI(){
            return i;
        }
    }

    public static void main(String[] args) {
        for (int i = 0; i <Constants2.values().length ; i++) {
            System.out.println(Constants2.values()[i]+"调用getDescription方法为"+Constants2.values()[i].getDescription());
        }
        System.out.println(Constants2.valueOf("Constants_D")+"调用getI方法为："+Constants2.valueOf("Constants_D").getI());
    }
}

import java.awt.*;

public class OverClass<T> {
    private T over;
    public T getOver(){
        return over;
    }
    public void setOver(T over){
        this.over = over;
    }

    public static void main(String[] args) {
        OverClass<Boolean> over1 = new OverClass<Boolean>();
        OverClass<Float> over2 = new OverClass<Float>();
        over1.setOver(true);
        over2.setOver(12.3F);
        Boolean b = over1.getOver();
        Float f = over2.getOver();
        System.out.println(b);
        System.out.println(f);
    }
}

import java.util.HashMap;
import java.util.Map;

public class MutiOverClass<K,V> {
    public Map<K,V> m = new HashMap<K,V>();
    public void put(K k,V v){
        m.put(k,v);
    }
    public V get(K k){
        return m.get(k);
    }

    public static void main(String[] args) {
        MutiOverClass<Integer,String> mu = new MutiOverClass<Integer, String>();
        for (int i = 0; i < 5; i++) {
            mu.put(i,"I am set "+i);
        }
        for (int i = 0; i < mu.m.size(); i++) {
            System.out.println(mu.get(i));
        }
    }
}

public class ArrayClass<T> {
    private T[] array;

    public void setArray(T[] array) {
        this.array = array;
    }

    public T[] getArray() {
        return array;
    }

    public static void main(String[] args) {
        ArrayClass<String> a = new ArrayClass<String>();
        String[] array = {"A","b","C"};
        a.setArray(array);
        for (int i = 0; i <a.getArray().length ; i++) {
            System.out.println(a.getArray()[i]);
        }
    }
}