心情日记 II

今天星期四
总觉得时间过得好快
转眼间已到了四月的最后一天了
五月的天即将来临

时间过得快 真是快
弹指一挥一周又一周的时间就这样过了
真希望人生有许多奇迹发生

Accessing non-static member variables from static methods

Many programmers, particularly when first introduced to Java, have problems with accessing member variables from their main method. The method signature for main is marked static - meaning that we don't need to create an instance of the class to invoke the main method. For example, a Java Virtual Machine (JVM) could call the class MyApplication like this :-
MyApplication.main ( command_line_args );

This means, however, that there isn't an instance of MyApplication - it doesn't have any member variables to access! Take for example the following application, which will generate a compiler error message.

public class StaticDemo
{
public String my_member_variable = "somedata"; public static void main (String args[])
{
// Access a non-static member from static method
System.out.println ("This generates a compiler error" +
my_member_variable );
}
}
If you want to access its member variables from a non-static method (like main), you must create an instance of the object. Here's a simple example of how to correctly write code to access non-static member variables, by first creating an instance of the object.public class NonStaticDemo
{
public String my_member_variable = "somedata";
public static void main (String args[])
{
NonStaticDemo demo = new NonStaticDemo();
// Access member variable of demo
System.out.println ("This WON'T generate an error" +
demo.my_member_variable );
}
}

心情日记

今天是四月八日
不知不觉 在新公司做了则整十一个月了
感觉时间过得好快
一切都已经好像好远了

今夜 躺在床上 却一点睡意也没有
薛之谦的认真的雪 - 反复听了好几次 觉得好好听
大家不妨去下载听听吧