第一种：
publicstaticvoidmain(Stringargs[]){
Scannerscn=newScanner(System.in);
System.out.print("第一个数：");
inta=scn.nextInt();
System.out.print("操作(+,-,*,/)：");
Stringoption=scn.next();
System.out.print("第二个数：");
intb=scn.nextInt();
intresult=0;
if("+".equals(option)){
result=a+b;
}
if("-".equals(option)){
result=a-b;
}
if("*".equals(option)){
result=a*b;
}
if("/".equals(option)){
result=a/b;
}
System.out.println("结果："+result);
}第二种：
publicstaticvoidmain(Stringargs[]){
Scannerscn=newScanner(System.in);
System.out.print("请输入第一个数:");
intoNumFirst=scn.nextInt();
System.out.print("请输入操作方式(+,-,*,/):");
Stringoption=scn.next();
System.out.print("请输入第二个数:");
intoNumSecond=scn.nextInt();
intresult=0;
switch(option){
case"+":
result=oNumFirst+oNumSecond;
break;
case"-":
result=oNumFirst-oNumSecond;
break;
case"*":
result=oNumFirst*oNumSecond;
break;
case"/":
try{
result=oNumFirst/oNumSecond;
}catch(ArithmeticExceptione){
e.printStackTrace();
System.out.println("除数不能为0");
}
break;
}
System.out.println("结果为："+result);
}第三种：
/**
*计算器类
*CreatedbyHDLon2016/11/30.
*/
publicclassOptioner{
privateintoNumFirst;//第一个数
privateintoNumSecond;//第二个数
publicintgetoNumFirst(){
returnoNumFirst;
}
publicvoidsetoNumFirst(intoNumFirst){
this.oNumFirst=oNumFirst;
}
publicintgetoNumSecond(){
returnoNumSecond;
}
publicvoidsetoNumSecond(intoNumSecond){
this.oNumSecond=oNumSecond;
}
publicOptioner(){
}
publicOptioner(intoNumFirst,intoNumSecond){
this.oNumFirst=oNumFirst;
this.oNumSecond=oNumSecond;
}
publicintgetReuslt(){
return0;
}
}1617181920212223242526272829
/**
*加法运算
*CreatedbyHDLon2016/11/30.
*/
{
@Override
publicintgetReuslt(){
returngetoNumFirst()+getoNumSecond();
}
}
/**
*减法运算
*CreatedbyHDLon2016/11/30.
*/
{
@Override
publicintgetReuslt(){
returngetoNumFirst()-getoNumSecond();
}
}
/**
*乘法运算
*CreatedbyHDLon2016/11/30.
*/
{
@Override
publicintgetReuslt(){
returngetoNumFirst()*getoNumSecond();
}
}
/**
*除法运算
*CreatedbyHDLon2016/11/30.
*/
{
@Override
publicintgetReuslt(){
if(getoNumSecond()==0){
System.out.println("除数不能为0");
return-1;
}else{
returngetoNumFirst()/getoNumSecond();
}
}
}
测试
publicstaticvoidmain(Stringargs[]){
Scannerscn=newScanner(System.in);
System.out.print("请输入第一个数:");
intoNumFirst=scn.nextInt();
System.out.print("请输入操作方式(+,-,*,/):");
Stringopt=scn.next();
System.out.print("请输入第二个数:");
intoNumSecond=scn.nextInt();
Optioneroptioner=null;
switch(opt){
case"+":
optioner=newAddOptioner();
break;
case"-":
optioner=newSubOptioner();
break;
case"*":
optioner=newMulOptioner();
break;
case"/":
optioner=newDivOptioner();
break;
}
optioner.setoNumFirst(oNumFirst);
optioner.setoNumSecond(oNumSecond);
System.out.println("结果为："+optioner.getReuslt());
}
‘贰’ java是什么java能干什么工作
Java作为面向对象的程序设计语言，由Sun Microsystems公司在1995年推出，包括JavaSE, JavaEE, JavaME等平台总称。那么，Java能做哪些工作呢？以下总结了四点：
第一，企业级应用开发。Java的安全性使其成为大型应用开发的首选，如第三方交易系统、银行前后台交易系统、医疗管理系统等。企业级应用开发领域的Java工程师需求量大，具有相关项目经验者可考虑该类工作。
第二，网页开发。Java开发的网页运行流畅，不易卡顿，因此越来越多企业采用Java构建网站。在Java培训中，常涉及HTML5、CSS、JavaScript、jQuery等前端技术以及AJAX等交互技术，培训后可从事Java网页开发工作。
第三，游戏开发。中国游戏行业蓬勃发展，Java的脚本语言与游戏语言无缝对接，且Java自身支持开发小游戏。因此，精通Java的人才在游戏开发领域有良好的就业前景。
第四，物联网。物联网作为新兴领域，人才需求量大。Java的跨平台特性使其在嵌入式程序开发中表现出色。学习Java，未来可以涉足物联网相关行业。
综上所述，Java的就业前景广阔，涉及多个方向。感兴趣的小伙伴们不妨来IT修真院官网免费体验任务，或者亲临线下分院感受学习氛围。修真院提供7天免费试学，试学期间可深入了解Java技术。
‘叁’ java面向对象编程题目
public class Rectangle
{
private double width;
private double height;
//无参构造器
public Rectangle()
{}
//有参构造器
public Rectangle(double width, double height)
{
this.width = width;
this.height = height;
}
//属性的get和set方法定义
public void setWidth(double width)
{
this.width = width;
}
public double getWidth()
{
return this.width;
}
public void setHeight(double height)
{
this.height = height;
}
public double getHeight()
{
return this.height;
}
//计算周长的方法
private double getPerimeter()
{
return (width+height)*2;
}
//计算面积的方法
private double getArea()
{
return width*height;
}
public static void main(String[] args)
{
Rectangle rec = new Rectangle(3.6,5.8);
System.out.println("The perimeter of Rectangle is:"+rec.getPerimeter());
System.out.println("The area of Rectangle is:"+rec.getArea());
}
}
‘肆’ java面向对象编程题目。要求用抽象类和接口
//abstract Shape形状类
publicabstractclassShape{
abstractdouble area();
abstractdouble perimeter();
}
//Rectangle继承Shape类
{
private double width;
publicdoublegetWidth(){
returnwidth;
}
publicvoidsetWidth(doublewidth){
this.width=width;
}
publicdoublegetHeight(){
returnheight;
}
publicvoidsetHeight(doubleheight){
this.height=height;
}
private double height;
Rectangle(){
}
Rectangle(double width,double height){
this.width=width;
this.height=height;
}
public double area(){
return width*height;
}
public double perimeter(){
return (width+height)*2;
}
}
//Circle类继承抽象类Shape
publicclassCircleextendsShape{
private final double PI=3.14;
private double radius;
Circle(){
}
Circle(double radius){
this.radius=radius;
}
publicdoublegetRadius(){
returnradius;
}
publicvoidsetRadius(doubleradius){
this.radius=radius;
}
public doublearea(){
returnradius*radius*PI;
}
public doubleperimeter(){
returnradius*2*PI;
}
}
/Triangle类继承抽象类Shape
{
private double di;
private double high;
Triangle(){
}
Triangle(double di,double high){
this.di=di;
this.high=high;
}
publicdoublegetDi(){
returndi;
}
publicvoidsetDi(doubledi){
this.di=di;
}
publicdoublegetHigh(){
returnhigh;
}
publicvoidsetHigh(doublehigh){
this.high=high;
}
public doublearea(){
return di*high*1/2;
}
public doubleperimeter(){
return di*3;//限等边三角形
}
}
//定义接口Shape
public interfaceShape{
publicdouble area();
publicdouble perimeter();
}
//Rectangle类实现接口Shape
{
private double width;
publicdoublegetWidth(){
returnwidth;
}
publicvoidsetWidth(doublewidth){
this.width=width;
}
publicdoublegetHeight(){
returnheight;
}
publicvoidsetHeight(doubleheight){
this.height=height;
}
private double height;
Rectangle(){
}
Rectangle(double width,double height){
this.width=width;
this.height=height;
}
public double area(){
return width*height;
}
public double perimeter(){
return (width+height)*2;
}
}
//Circle类实现接口Shape
{
private final double PI=3.14;
private double radius;
Circle(){
}
Circle(double radius){
this.radius=radius;
}
publicdoublegetRadius(){
returnradius;
}
publicvoidsetRadius(doubleradius){
this.radius=radius;
}
public doublearea(){
returnradius*radius*PI;
}
public doubleperimeter(){
returnradius*2*PI;
}
}
//Triangle类实现接口Shape
{
private double di;
private double high;
Triangle(){
}
Triangle(double di,double high){
this.di=di;
this.high=high;
}
publicdoublegetDi(){
returndi;
}
publicvoidsetDi(doubledi){
this.di=di;
}
publicdoublegetHigh(){
returnhigh;
}
publicvoidsetHigh(doublehigh){
this.high=high;
}
public doublearea(){
return di*high*1/2;
}
public doubleperimeter(){
return di*3;//限等边三角形
}
}
//测试类ShapeTest
publicclassShapeTest{
publicstaticvoidmain(String[]args){
Circlec1=newCircle(3);//圆类有参初始化
Circlec2=newCircle();//圆类无参初始化
c2.setRadius(3);//初始化c2的半径
Squares1=newSquare(3);//方形类有参初始化
Squares2=newSquare();//方形类无参初始化
s2.setSide(5);//初始化s2的边长
Trianglet1=newTriangle(5,6);//三角类有参初始化
Trianglet2=newTriangle();//三角类无参初始化
t2.setDi(2);//初始化t2的底
t2.setHigh(6);//初始化t2的高
print("c1的面积:"+c1.area()+" c2的面积"+c2.area());
print("c1的周长:"+c1.perimeter()+" c2的周长"+c2.perimeter());
print("s1的面积:"+s1.area()+" s2的面积"+s2.area());
print("s1的周长:"+s1.perimeter()+" s2的周长"+s2.perimeter());
print("t1的面积:"+t1.area()+" t2的面积"+t2.area());
print("t1的周长:"+t1.perimeter()+" t2的周长"+t2.perimeter());
}
//定义静态打印方法
public static void print(Object object){
System.out.println(object);
}
}
//打印结果
c1的面积:28.26 c2的面积28.26
c1的周长:18.84 c2的周长18.84
s1的面积:9.0 s2的面积25.0
s1的周长:12.0 s2的周长20.0
t1的面积:15.0 t2的面积6.0
t1的周长:15.0 t2的周长6.0