字符串:重复

". ".repeat(7)  // Seven period-with-space pairs: . . . . . . . 

Java 11中的新方法是String::repeat，它完全符合你的要求:

String str = "abc";
String repeated = str.repeat(3);
repeated.equals("abcabcabc");

它的Javadoc说:

/**
 * Returns a string whose value is the concatenation of this
 * string repeated {@code count} times.
 * <p>
 * If this string is empty or count is zero then the empty
 * string is returned.
 *
 * @param count number of times to repeat
 *
 * @return A string composed of this string repeated
 * {@code count} times or the empty string if this
 * string is empty or count is zero
 *
 * @throws IllegalArgumentException if the {@code count} is
 * negative.
 *
 * @since 11
 */ 

Java 8的字符串。join结合Collections.nCopies提供了一种简洁的方法:

// say hello 100 times
System.out.println(String.join("", Collections.nCopies(100, "hello")));

Commons only StringUtils.repeat（）

用法:

String str = "abc";
String repeated = StringUtils.repeat(str, 3);

repeated.equals("abcabcabc");

试试这个吧:

public static char[] myABCs = {'a', 'b', 'c'};
public static int numInput;
static Scanner in = new Scanner(System.in);

public static void main(String[] args) {
    System.out.print("Enter Number of Times to repeat: ");
    numInput = in.nextInt();
    repeatArray(numInput);
}

public static int repeatArray(int y) {
    for (int a = 0; a < y; a++) {
        for (int b = 0; b < myABCs.length; b++) {
            System.out.print(myABCs[b]);                
        }
        System.out.print(" ");
    }
    return y;
}

这里有一种只使用标准String函数而没有显式循环的方法:

// create a string made up of  n  copies of  s
repeated = String.format(String.format("%%%ds", n), " ").replace(" ",s);

如果担心性能问题，只需在循环中使用StringBuilder，并在循环退出时执行. tostring()。见鬼，编写自己的Util类并重用它。最多5行代码。