java接口调用讲解

1、1 简单ATM实现思路Test里面是多态，父类是abstract抽象类，不让他创建对象Public void test（Atm bb） bbDeposit（100）； bbDraw（100）；Test t = new Test（）；If（num=1）t.test（new Credit（）；/信用卡取款操作，多态 Else if（num=2）t.test（new Icard（）；/存储卡取款2 ObjectObject所有类，超类存放任意类型，只能存放对象数组，不能是int类型Object 和 object 之间的区别方法中形参是object类型时，任何类型的参数都可以传递去执行方法中形参是ob

2、ject ,只有对象数组可以传入执行ObjectDemo.javapackage com.wwww.eec.test;public class ObjectDemo public void objTest(Object object)System.out.println("objTest()");public void objArray(Test t) / TODO Auto-generated method stubTest.javapackage com.wwww.eec.test;public class Test public static void main(St

3、ring args) ObjectDemo od = new ObjectDemo();int str = new int10; Test t = new Test10; /在同一个类中不用导包od.objTest(str);od.objArray(t);3 标准封装类toString（）方法Object中的toString方法返回的是getClass（）.getName（）+Integer.toHexString（hasCode（）自定义对象重写toString（）方法可以根据用户意愿输出对象信息package com.wwww.eec.test;public class Student p

4、rivate String name;private char sex;private int age;public Student() /无参构造方法super();/ TODO Auto-generated constructor stubpublic Student(String name, char sex, int age) /有参构造方法super(); = name;this.sex = sex;this.age = age;public String getName() /get，set方法return name;public void setName(St

5、ring name) = name;public char getSex() return sex;public void setSex(char sex) this.sex = sex;public int getAge() return age;public void setAge(int age) this.age = age;Overridepublic int hashCode() /哈希构造final int prime = 31;int result = 1;result = prime * result + age;result = prime * resu

6、lt + (name = null) ? 0 : name.hashCode();result = prime * result + sex;return result;Overridepublic boolean equals(Object obj) /重写equals方法if (this = obj)return true;if (obj = null)return false;if (getClass() != obj.getClass()return false;Student other = (Student) obj;if (age != other.age)return fals

7、e;if (name = null) if ( != null)return false; else if (!name.equals()return false;if (sex != other.sex)return false;return true;Overridepublic String toString() /最后toStringreturn "Student name=" + name + ", sex=" + sex + ", age=" + age + ""

8、return super.toString（）；/String内容重写了否则是1524568StuTest.javapackage com.wwww.eec.test;public class stuTest public static void main(String args) Student stu = new Student();stu.setAge(18);stu.setName("图图");stu.setSex('男');System.out.println(stu.toString();Student stu1 = new Student(&q

9、uot;图图",'男', 6);Student stu2 = new Student("图图",'男', 6);System.out.println(stu1=stu2); /返回的是false 传递的是虚地址System.out.println(stu1.equals(stu2);/equals()方法在Object中比较的是虚地址，重写了equals可以比较内容4 接口1) 接口是一些抽象方法的集合（在接口中存放的是抽象方法，不能存放普通方法只做方法 的声明）2) 接口中没有变量，只能有public static final 修

10、饰的静态常量，三个修饰符可以省略使用接口的方法1 com.wwww.eec.vo 实体类中 先定义User.java2 再写接口UserInterface.java，抽象方法的调用3 实现包imp 写 执行的类4 Dao包 用户名密码5 最后测试类 模拟客户端1 User.javapackage com.wwww.eec.vo;public class User private String name;private String pwd;public User() super();/ TODO Auto-generated constructor stubpublic User(String

11、 name, String pwd) super(); = name;this.pwd = pwd;public String getName() return name;public void setName(String name) = name;public String getPwd() return pwd;public void setPwd(String pwd) this.pwd = pwd;Overridepublic int hashCode() final int prime = 31;int result = 1;result =

12、prime * result + (name = null) ? 0 : name.hashCode();result = prime * result + (pwd = null) ? 0 : pwd.hashCode();return result;Overridepublic boolean equals(Object obj) if (this = obj)return true;if (obj = null)return false;if (getClass() != obj.getClass()return false;User other = (User) obj;if (nam

13、e = null) if ( != null)return false; else if (!name.equals()return false;if (pwd = null) if (other.pwd != null)return false; else if (!pwd.equals(other.pwd)return false;return true;Overridepublic String toString() return "User name=" + name + ", pwd=" + pwd +

14、""2 UserInterface.javapackage er;import com.wwww.eec.vo.User;public /*class*/interface UserInterface /接口要调用的方法boolean /*int*/ login(User user);int register(User user);3 UserImp1package er.imp1;import com.wwww.eec.dao.UserDao;import er.UserInt

15、erface;import com.wwww.eec.vo.User;public class UserImp1 implements UserInterface /UserImp1执行类public boolean login(User user)UserDao ud = new UserDao();boolean falg = ud.userLoin(user);return falg;Overridepublic int register(User user) / TODO Auto-generated method stubreturn 0;4 UserDao.javapackage

16、com.wwww.eec.dao;import java.util.Scanner;import com.wwww.eec.vo.User;public class UserDao boolean flag = false;/*String user = "admin","admin"*/public boolean /*getUser()*/userLoin(User user)/*User user = new User();user.setName("admin");user.setPwd("888888")

17、;*/String client = user.getName(),user.getPwd();System.out.println("请输入用户名");Scanner scan = new Scanner(System.in);String userName = scan.next(); System.out.println("请输入密码");String UserPwd =scan.next();for (int i= 0;i<client.length;i+)if(userName.equals(clienti)&&UserP

18、wd.equals(clienti+1)System.out.println("登录成功");flag = true;break;elseSystem.out.println("登录失败");flag = false;return flag;/*public boolean getUser() /没有写void的方法必须写返回值System.out.println("请输入用户名");Scanner scan = new Scanner(System.in);String userName = scan.next(); System.out.println("请输入密码");String UserPwd =scan.next();for (int i= 0;i&