Home > Java > JavaBase > body text

How to assign value in java

angryTom
Release: 2019-11-15 10:25:16
Original
18232 people have browsed it

How to assign value in java

java怎么赋值

java的赋值语句是“=”号,比如把1赋值给a可以写:int a = 1;,如果是String类型可以写:String a = "1";对象可以写成User u1 = new User();

了解了基本的赋值语句,下面我们来学学基本类型数据的赋值、String类型数据的赋值和自定义数据类型赋值的区别。(推荐教程:java教程

一、基本类型数据赋值

实验1 :定义一个int 类型变量a = 3,并将a 赋值给int b,然后将a ,赋值为5,那么b 的值是3 还是5 呢?

int a = 3;
int b = a ;
a = 5 ;
System.out.println(" a = " + a+" b = "+b );
Copy after login

运行程序 ,打印结果为 :

a = 5 b =3
Copy after login

我们看到,b并没有随a的改变而改变。基本数据类型是值赋值。

二、String类型数据赋值

实验2:定义一个String类型变量s1 赋值为“a”,并将s1赋值给String s2 ;然后将s1赋值为“b”,那么s2的值是 “a”还是 “b”?

String s1 = "a" ;
String s2 = s1;
s1 = "b" ;
System.out.println("s1 = "+s1+" s2 = "+ s2);
Copy after login

运行程序 ,打印结果为 :

s1 = b s2 =a
Copy after login

我们看到,s2并没有随s1的改变而改变。

三、自定义数据类型赋值

实验3: 创建一个TUser u1 ,并将u1赋值给TUser u2 ,将 u1重新赋值 ,u2会随着u1改变而改变吗 ?

TUser u1 = new TUser();
u1.setId(1);
TUser u2 = u1 ;
u1 = new TUser();
u1.setId(2);
System.out.println("ui :"+u1 + "\t\n" +"u2 : "+ u2);
Copy after login


运行程序,打印结果为:

u1 :TUser(id=2)
u2 : TUser(id=1)
Copy after login

我们看到u2并没有随着u1的改变而改变。如果我们不改变u1指向的地址,而是改变u1指向地址所对应的数据(即将 u1 = new TUser(); 注释掉)。那么u1,u2 打印的记过将都会是 TUser(id=2)

通过以上三个实验我们发现:

● 变量之间的赋值,可以说没有所谓的值赋值和地址赋值。

● 简而言之,将一个变量a赋值给另一个变量b,是将这个变量a的值,拷贝一份给变量b(如果a是引用类型,就拷贝引用,如果是基本类型,就拷贝原始值)

The above is the detailed content of How to assign value in java. For more information, please follow other related articles on the PHP Chinese website!

Related labels:
source:php.cn
Statement of this Website
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn
Popular Tutorials
More>
Latest Downloads
More>
Web Effects
Website Source Code
Website Materials
Front End Template
About us Disclaimer Sitemap
php.cn:Public welfare online PHP training,Help PHP learners grow quickly!