今天第六天学习了java的类的知识，知识点有，类的构造，类的结构，this关键字，set和get方法。 private私有化的作用和形式，无参构造和有参构造，匿名对象，形式参数，成员变量和局部变量的区别。
学习的东西有点多，做了比较多的练习，对类已经比较熟练的使用了。
1。private封装
package java1;
public class jiujiuchengfa {
public static void main (String[]args) {
person p1=new person();
p1.name=”张三”;
p1.setAge(101);
System.out.println(p1.getAge());
}
}
class person{
String name;
private int age;
public void setAge(int a) {
if(a>0&&a<100) {
age=a;
}else {System.out.println(“请输入正确年龄”);}
}
public int getAge() {
return age;
}
public void speak() {
System.out.println(name+”….”+age);
}
}
2.封装的练习
package java1;
import java.util.*;
public class jiujiuchengfa {
public static void main (String[]args) {
person p1=new person();
Scanner in=new Scanner(System.in);
System.out.println(“请输入年龄：”);
p1.setage(in.nextInt());
System.out.println(p1.getage());
p1.speak();
}
}
class person{
String name;
private int age;
public void setage(int a) {
if(a>0&&a<100) {
age=a;
}else {
System.out.println(“错”);
}
}
public int getage() {
return age;
}
public void speak() {
System.out.println(name+”….”+age);
}
}
3.private和this的使用练习
package java1;
import java.util.*;
public class jiujiuchengfa{
public static void main(String[]args) {
Scanner in=new Scanner(System.in);
car c1=new car();
System.out.println(“请输入车牌号和颜色：”);
c1.setnum(in.nextInt());
c1.color=in.next();
c1.run();
}
}
class car{
private int num;
String color;
public void setnum(int num) {
if(num>0&&num<100) {
this.num=num;
}else {System.out.println(“请输入正确数字”);}
}
public int getnum() {
return num;
}
public void run() {
System.out.println(num+color);
}
}
4类的构造
package java1;
import java.util.*;
public class student {
public static void main(String[]args) {
Scanner in=new Scanner(System.in);
stu p1=new stu();
System.out.println(“请输入名字：”);
p1.setName(in.next());
System.out.println(“请输入年龄：”);
p1.setAge(in.nextInt());
p1.run();
}
}
class stu{
private String name;
public void setName(String name) {
this.name=name;
}
public String getName() {
return this.name;
}
private int age;
public void setAge(int age) {
if(age>0&&age<100) {
this.age=age;
System.out.println(“输入正确！”);
}else {System.out.println(“输入错误！”);}
}
public int getAge() {
return this.age;
}
public void run() {
System.out.println(“年龄是：”+age+”名字是：”+name);
}
}
5构造函数的练习
package java1;
class youcan{
public static void main(String[]args) {
Gouzao p1=new Gouzao();//空参构造
p1.setPrice(10);
p1.setBrand(“苹果”);
p1.show();
Gouzao p2=new Gouzao(“小米”,98);//有参构造
p2.show();
}
}
class Gouzao{//构造类
private String brand;//品牌成员参数
private int price;//价格成员参数
public Gouzao() {}//空参构造
public Gouzao(String brand,int price)
{
this.brand=brand;
this.price=price;
}//有参构造
public void setBrand(String brand){
this.brand=brand;
}
public String getBrand() {
return this.brand;
}
public void setPrice(int price) {
this.price=price;
}
public int getPrice() {
return this.price;
}
public void show() {
System.out.println(brand+price);
}
}
6.构造函数（有参构造，无参构造），private，this的练习
package java1;
public class demo {
public static void main(String[]args) {
student p1=new student();
p1.setAge(10);
p1.setScore(20);
p1.show();
student p2=new student(10,10);
p2.show();
}
}
class student{
private int age;
private int score;
public student(){};
public student(int age,int score) {
this.age=age;
this.score=score;
}
public void setAge(int age) {
this.age=age;
}
public int getAge() {
return this.age;
}
public void setScore(int score) {
this.score=score;
}
public int getScore() {
return this.score;
}
public void show() {
System.out.println(age+”/t”+score);
}
}
7.构造函数
package javahome;
import java.util.*;
public class demo {
public static void main(String[]args) {
System.out.println(“请输入长宽”);
Scanner in=new Scanner(System.in);
Stu p1=new Stu();
p1.setWide(in.nextInt());
p1.setHigh(in.nextInt());
p1.area();
Stu p2=new Stu(in.nextInt(),in.nextInt());
p2.area();
}
}
class Stu{
private int wide;
private int high;
public Stu() {};
public Stu(int wide,int high) {
this.wide=wide;
this.high=high;
}
public void setWide(int wide){
this.wide=wide;
}
public int getWide() {
return this.wide;
}
public void setHigh(int high) {
this.high=high;
}
public int getHigh() {
return this.high;
}
public void area() {
int area=high*wide;
int perimeter=(high+wide)*2;
System.out.println(“面积是”+area+”周长是”+perimeter);
}
}
8,类的构造练习
package javahome;
public class com {
public static void main(String[]args) {
System.out.println(“未运行”);
}
}
class One{
private int One1;
private int One2;
public One() {}
public One(int One1,int One2) {
this.One1=One1;
this.One2=One2;}
public void setOne1(int one1) {
this.One1=One1;
}
public int getOne1() {
return this.One1;
}
public void setOne2(int One2) {
this.One2=One2;
}
public int getOne2() {
return this.One2;
}
public void run() {}
}