发表于 2012-07-28 15:24:28 by 月小升
Java的基本的数据类型一共有8种
String 不是一个基础数据类型，String是一个char数组 char[]
| 类型 |
说明 |
范围 |
默认值 |
| byte |
8比特类型 |
(-128 to 127)-2^7 to 2^7-1 |
0 |
| short |
16比特类型 |
(–32,768 to 32,767)-2^15 to 2^15-1 |
0 |
| int |
32比特类型 |
(–2,147,483,648 to 2,147,483,647)-2^31 to 2^31-1 |
0 |
| long |
64比特类型 |
(–9,223,372,036,854,775,808 to 9 ,223,372,036,854,775,807)-2^63 to 2^63-1 |
0L |
| float |
32比特类型,符合IEEE 754标准的浮点数 |
(±1.4E-45 to ±3.4028235E38) |
0.0f |
| double |
64比特类型,符合IEEE 754标准的浮点数 |
(±4.9E-324 to ±1.7976931348623157E308) |
0.0d |
| boolean |
1 比特 |
只有两种值true,false |
false |
| char |
16比特类型 unsigned integer |
(0 -- 65535) |
'u0000'
|
计算机单位换算
1 byte = 8 bits.
1 kilobyte (K / Kb) = 2^10 bytes = 1,024 bytes.
1 megabyte (M / MB) = 2^20 bytes = 1,048,576 bytes.
1 gigabyte (G / GB) = 2^30 bytes = 1,073,741,824 bytes. |
1 byte = 8 bits.
1 kilobyte (K / Kb) = 2^10 bytes = 1,024 bytes.
1 megabyte (M / MB) = 2^20 bytes = 1,048,576 bytes.
1 gigabyte (G / GB) = 2^30 bytes = 1,073,741,824 bytes.
写个例子来感觉下数据类型
BasicType.java
/**
java-er.com
learn java is so easy
Basic Type
*/
public class BasicType {
public static void main(String[] args){
byte b = 10; // b < 127 and b >-128
System.out.println(b);
short s = 10;
System.out.println(s);
int i = 3;
System.out.println(i);
long l = 199999999L;
System.out.println(l);
float f = 2.34f;
System.out.println(f);
double d = 3.1415926;
System.out.println(d);
boolean bx = true;
System.out.println(bx);
char c = 97; //97 equals 'a'
char c1 = 'a';
System.out.println(c);
System.out.println(c1);
}
} |
/**
java-er.com
learn java is so easy
Basic Type
*/
public class BasicType {
public static void main(String[] args){
byte b = 10; // b < 127 and b >-128
System.out.println(b);
short s = 10;
System.out.println(s);
int i = 3;
System.out.println(i);
long l = 199999999L;
System.out.println(l);
float f = 2.34f;
System.out.println(f);
double d = 3.1415926;
System.out.println(d);
boolean bx = true;
System.out.println(bx);
char c = 97; //97 equals 'a'
char c1 = 'a';
System.out.println(c);
System.out.println(c1);
}
}
命令行：
10
10
3
199999999
2.34
3.1415926
true
a
a |
10
10
3
199999999
2.34
3.1415926
true
a
a
String(字符串) 是一个常用的类型, String 类型用双引号括起来。
String s1 = "My name is ";
String s2 = new String("Jack");
String s3 = s1 + s2;
System.out.println(s3); |
String s1 = "My name is ";
String s2 = new String("Jack");
String s3 = s1 + s2;
System.out.println(s3);
输出
This entry was posted in
JAVA and tagged
java,
java基础教程. Bookmark the
permalink.
月小升QQ 2651044202, 技术交流QQ群 178491360
首发地址：
月小升博客 –
https://java-er.com/blog/java-basic/
无特殊说明，文章均为月小升原创，欢迎转载，转载请注明本文地址，谢谢
您的评论是我写作的动力.