1五行五列的*

*****

*****

*****

*****

*****

public static void main(String[] args) {        for (int i = 1; i <= 5; i++) {            for (int j = 1; j <= 5; j++) {                System.out.print("*");            }            System.out.println("*");        }    }

2.

*

**

***

****

*****

public static void main(String[] args) {        for (int i = 0; i < 5; i++) {            for (int j = 0; j <= i; j++) {                System.out.print("*");            }            System.out.println();        }    }

 3.

    *

   **

  ***

 ****

*****

public static void main(String[] args) {        for (int i = 0; i < 5; i++) {            for (int j = 0; j < (5-i-1); j++) {                System.out.print(" ");            }            for (int j = 0; j <= i ; j++) {                System.out.print("*");            }            System.out.println();        }    }

 4.

    *

   ***

  *****

 *******

*********

public static void main(String[] args) {        for (int i = 1; i <= 5; i++)//正序输出上半部分        {            for (int j = 1; j <= 5 - i; j++)            {                System.out.print(" ");            }            for (int k = 1; k <= i * 2 - 1; k++) {                System.out.print("*");            }            System.out.println();        }    }

 6.

   *

  ***

 *****

*******

 *****

  ***

   *

public static void main(String[] args) {        int lay;        lay = 7;//菱形的总长度        for(int i = 1; i <= (lay+1)/2; i++)//正序输出上半部分        {            for(int j = 1; j <=(lay+1)/2-i ; j++)//输出空格            {                System.out.print(" ");            }            for(int k = 1; k <= i*2-1; k++)            {                System.out.print("*");            }            System.out.println();//换行        }        for(int i =(lay+1)/2-1;i >= 1; i --)//倒序输出下半部分        {            for(int j = 1; j <= (lay+1)/2-i; j++)//输出空格            {                System.out.print(" ");            }            for(int k = (lay+1)/2-i; k <=(lay+1)/2-2+i; k ++)//(lay+1)/2-1即为下半个三角形            {                System.out.print("*");            }            System.out.println();        }    }