JAVA布置环境

1.安装JDK

下载安装包地址:Java Downloads | Oraclehttp://www.oracle.com/technetwork/java/javase/downloads/index.html

 将jdk的bin目录添加到系统环境中

cmd执行javac,出现结果说明安装成功

2.写个小demo

shushu.java

/**
 * 输出99到0
 */
public class shushu {
	public static void main(String[] args) {
		int number = 99;
		while(number >= 0){
			System.out.println(number);
			number = number - 1;
		}
	}
}

编译为shushu.class

javac shushu.java

 执行shushu.class(注意,不要加.class)

java shushu