如何在Java中查找运行时提供的参数数量?
Java命令行参数是在程序运行时传递的参数。即为了使程序动态化,可能存在我们在运行时传递参数的情况。通常,通过命令行参数,它们会被传递,并且有多种方法可以找到提供的参数数量并获取每个参数的值。
每个Java程序都通过 main 方法启动,该方法是静态的,这意味着 main 方法不需要实例化。我们可以直接打电话。因此,调用了一个Java文件名,第一个开始的方法是 main() 方法,它有一个输入参数,它是 String[](字符串数组数据类型)
句法 :
Java
// Java code with main method.
// It has an input argument
// with String[] datatype
import java.io.*;
class GFG {
public static void main (String[] args) {
}
}
Java
// Java program to count the number of
// command line arguments at runtime
public class GFG {
public static void main(String[] arguments) {
String wordToFind = "GFG.";
System.out.println("Arguments passed at runtime. " +
"We can get that by using args.length and it is " +
arguments.length + " here ");
for(int i = 0; i < arguments.length; i++) {
if (arguments[i].equalsIgnoreCase(wordToFind)) {
System.out.println("Provided word "+
wordToFind + " is present " +
"and it is at location " + (i+1));
}
}
}
}
Java
// Java program to count
// the number of arguments
// using args.length
// main() method is a static method which
// gets called first when java program runs
public class GFG {
public static void main(String[] arguments) {
System.out.println("Arguments passed at runtime. "+
"We can get that by using args.length and it is = " +
arguments.length + " here ");
for(int i = 0; i < arguments.length; i++) {
System.out.println("Argument " + i + " = "
+ arguments[i]);
}
}
}
当Java代码运行时,我们可以在运行时传递参数作为
command prompt > java
或在任何喜欢的IDE(如 Eclipse )中,我们也可以在运行时传递参数,如截图所示
示例 1:
Java
// Java program to count the number of
// command line arguments at runtime
public class GFG {
public static void main(String[] arguments) {
String wordToFind = "GFG.";
System.out.println("Arguments passed at runtime. " +
"We can get that by using args.length and it is " +
arguments.length + " here ");
for(int i = 0; i < arguments.length; i++) {
if (arguments[i].equalsIgnoreCase(wordToFind)) {
System.out.println("Provided word "+
wordToFind + " is present " +
"and it is at location " + (i+1));
}
}
}
}
在Eclipse中,我们可以以上述方式提供参数:
屏幕 1
屏幕 2
在Java应用程序下 –> 单击参数。在程序参数下,提供以下屏幕中指定的所需参数
在运行代码时,我们可以看到下面的输出
示例 2:查看命令行参数中是否提供了“GFG”
Java
// Java program to count
// the number of arguments
// using args.length
// main() method is a static method which
// gets called first when java program runs
public class GFG {
public static void main(String[] arguments) {
System.out.println("Arguments passed at runtime. "+
"We can get that by using args.length and it is = " +
arguments.length + " here ");
for(int i = 0; i < arguments.length; i++) {
System.out.println("Argument " + i + " = "
+ arguments[i]);
}
}
}
使用命令提示符,我们可以找到如下图所示的参数:
我们可以使用 cmd 提示符和命令行运行Java程序来查找参数的数量是:
java Class_Name “Statement “
It will give us the number of arguments in the double quotes.