import java.util.Scanner;

public class IfElseTest{
    public static void main(String args[]){
        IfElseTest ieT = new IfElseTest();
        args = new String[5];  //注意要，预先给args分配空间，
        Scanner in = new Scanner(System.in); 
        args[0]= in.next();
        ieT.go(args);
        in.close();
    }
    public void go(String sa[]){
        System.out.println(sa.length);
        if(sa.length == 0){
            System.out.println("无参数");
        }
        else {
            String s = sa[0];
            if(s.equals("true")||s.equals("TRUE")){
                System.out.println("OK");
            }
            else if(s.equals("false")||s.equals("FALSE")){
                System.out.println("NOT OK");
            }
            else {
                System.out.println("无效的命令");
            }
        }
    }
}

ps:函数里面的参数（String [ ] args）和（String args [ ]）两种写法都是表示字符串数组args[ ].