JavaSE 基础 第39节 接口的应用

package com.java1995;
/**
* 1.定义接口:打印
* @author Administrator
*
*/
public interface Modifier {
/**
* 均等价于public abstract void 方法名
*/
void print();
public void print1();
abstract void print2();
public abstract void print3();
abstract public String print4();

}

package com.java1995;
/**
* 2.实现接口:打印
* @author Administrator
*
*/
public class Modifier2 implements Modifier{

@Override
public void print() {
// TODO Auto-generated method stub
System.out.println("void");

}

@Override
public void print1() {
// TODO Auto-generated method stub
System.out.println("public void");

}

@Override
public void print2() {
// TODO Auto-generated method stub
System.out.println("abstract void");

}

@Override
public void print3() {
// TODO Auto-generated method stub
System.out.println("public abstract void");

}

@Override
public String print4() {
// TODO Auto-generated method stub
System.out.println("abstract public String");
return null;

}

}

package com.java1995;
/**
* 3.调用接口:打印
* @author Administrator
*
*/
public class ModifierTest {

public static void main(String[] args) {
//多态
Modifier m=new Modifier2();
m.print();
m.print1();
m.print2();
m.print3();
m.print4();
}

}

package com.java1995;
/**
* 2.实现接口:加减乘除
* @author Administrator
*
*/
public class MTest implements Jia,Jian,Cheng,Chu {

@Override
public int chu(int a, int b) {
// TODO Auto-generated method stub
return a/b;
}

@Override
public int cheng(int a, int b) {
// TODO Auto-generated method stub
return a*b;
}

@Override
public int jian(int a, int b) {
// TODO Auto-generated method stub
return a-b;
}

@Override
public int jia(int a, int b) {
// TODO Auto-generated method stub
return a+b;
}

}

package com.java1995;
/**
* 3.调用接口:加减乘除
* @author Administrator
*
*/
public class MathTest {

public static void main(String[] args) {
MTest mt=new MTest();
System.out.println("使用引用对象调用方法");
System.out.println("a+b="+mt.jia(15, 3));
System.out.println("a-b="+mt.jian(15, 3));
System.out.println("a*b="+mt.cheng(15, 3));
System.out.println("a/b="+mt.chu(15, 3));

/**
* 接口类型引用变量，重点！
*/
Jia mJia=mt;
Jian mJian=mt;
Cheng mCheng=mt;
Chu mChu=mt;
System.out.println("使用接口类型引用调用");
System.out.println("a+b="+mJia.jia(15,3));
System.out.println("a-b="+mJian.jian(15, 3));
System.out.println("a*b="+mCheng.cheng(15,3));
System.out.println("a/b="+mChu.chu(15, 3));
}

}

/**
* 1.定义接口:加减乘除
*/

//加法接口
interface Jia{
int jia(int a,int b);
}
//减法接口
interface Jian{
int jian(int a,int b);
}
//乘法接口
interface Cheng{
int cheng(int a,int b);
}
//除法接口
interface Chu{
int chu(int a,int b);
}