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Java基本数据类型

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Java基本数据类型

八种基本类型

  • 六种数字类型(四个整数型,两个浮点型):
    • 字节型byte 8位
    • 短整型short 16位
    • 整型int 32位
    • 长整型long 64位
    • 单精度float 32位
    • 双精度double 64位
  • 一种字符类型:
    • 字符型char 8位
  • 一种布尔型:
    • 布尔型:boolean 8位,可存储»True»和»false»

Integer是int的封装,跟int的表示范围一样

引用数据类型

包括:类、接口、数组

Java中各种数据的默认值

8种基本类型的初始值:

  • byte:0
  • short:0
  • int:0
  • long:0
  • float:0.0
  • double:0.0
  • char: (一个空格)
  • boolean:false
  • 引用数据类型:
  • String:null
  • a[0]:0
  • cha[0]: (一个空格)

附代码

//////TestMain.java::::
package com.main;
import com.bean.Test;
public class TestMain {
    public static void main(String[] args) {
       Test stu1=new Test();
       System.out.println("8种基本类型的初始值:");
       System.out.println("byte:"+stu1.getBytes());
       System.out.println("short:"+stu1.getShorts());
       System.out.println("int:"+stu1.getInts());
       System.out.println("long:"+stu1.getLongs());
       System.out.println("float:"+stu1.getFloats());
       System.out.println("double:"+stu1.getDoubles());
       System.out.println("char:"+stu1.getChars());
       System.out.println("boolean:"+stu1.isBooleans());
       System.out.println("引用数据类型:");
       System.out.println("String:"+stu1.getStr());
       int[] aa=stu1.getA();
       System.out.println("a[0]:"+aa[0]);
       char[] cha=stu1.getCha();
       System.out.println("cha[0]:"+cha[0]);
    }
}
//////Test.java:::::
package com.bean;
public class Test {
    //8种基本数据类型
    private byte bytes;
    private short shorts;
    private int ints;
    private long longs;
    private float floats;
    private double doubles;
    private char chars;
    private boolean booleans;
    public byte getBytes() {
       return bytes;
    }
    public void setBytes(byte bytes) {
       this.bytes = bytes;
    }
    public short getShorts() {
       return shorts;
    }
    public void setShorts(short shorts) {
       this.shorts = shorts;
    }
    public int getInts() {
       return ints;
    }
    public void setInts(int ints) {
       this.ints = ints;
    }
    public long getLongs() {
       return longs;
    }
    public void setLongs(long longs) {
       this.longs = longs;
    }
    public float getFloats() {
       return floats;
    }
    public void setFloats(float floats) {
       this.floats = floats;
    }
    public double getDoubles() {
       return doubles;
    }
    public void setDoubles(double doubles) {
       this.doubles = doubles;
    }
    public char getChars() {
       return chars;
    }
    public void setChars(char chars) {
       this.chars = chars;
    }
    public boolean isBooleans() {
       return booleans;
    }
    public void setBooleans(boolean booleans) {
       this.booleans = booleans;
    }
    //引用数据类型
    private String str;
    private int[] a=new int[4];
    private char[] cha=new char[4];
    public char[] getCha() {
       return cha;
    }
    public void setCha(char[] cha) {
       this.cha = cha;
    }
    public int[] getA() {
       return a;
    }
    public void setA(int[] a) {
       this.a = a;
    }
    public String getStr() {
       return str;
    }
    public void setStr(String str) {
       this.str = str;
    }
}

参考

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