day11-final关键字用于修饰局部变量
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42
day11/src/com/inmind/final01/Demo02.java
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42
day11/src/com/inmind/final01/Demo02.java
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package com.inmind.final01;
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import java.util.Arrays;
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/*
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final关键字用于修饰局部变量
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局部变量:在方法中定义的变量
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1.基本数据类型:保存的值真正的值,表示该值赋值之后不能被修改的
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2.引用数据类型: 保存的值是地址值。引用数据类型地址不变,所指向的内容可以改变
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*/
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public class Demo02 {
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public static void main(String[] args) {
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//基本数据类型被final修饰
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final int i = 10;//常量
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System.out.println(i);
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final int j;//先定义后赋值
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j = 20;
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System.out.println(j);
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System.out.println("---------------------------");
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//引用数据类型被final修饰(数组、类、接口)
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final int[] arr = {1, 2, 3};//arr中保存的是地址,如果添加了final,那就表示arr不能改变,也就是地址不能改变
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//arr = new int[]{4, 5, 6};//这里改变了arr中的地址,不允许的
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System.out.println(Arrays.toString(arr));
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//只要地址不变,地址对应的堆中空间的值是可以改变的
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arr[0] = 4;
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arr[1] = 5;
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arr[2] = 6;
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System.out.println(Arrays.toString(arr));
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//创建一个类的对象
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final Student s = new Student("张三", 20);//s是一个对象名,s是一个引用数据类型,保存的是地址
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System.out.println(s);
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System.out.println(s.getName());
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//s = new Student("李四", 22);//这里改变了s中的地址,不允许的
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s.setName("李四");//只要地址不变,地址对应的堆中空间的值是可以改变的
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System.out.println(s);
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System.out.println(s.getName());
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}
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}
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27
day11/src/com/inmind/final01/Student.java
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27
day11/src/com/inmind/final01/Student.java
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package com.inmind.final01;
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public class Student {
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String name;
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int age;
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public Student(String name, int age) {
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this.name = name;
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this.age = age;
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}
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public String getName() {
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return name;
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}
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public void setName(String name) {
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this.name = name;
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}
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public int getAge() {
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return age;
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}
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public void setAge(int age) {
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this.age = age;
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}
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}
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