用java程序打印出菱形

如图所示,打印出如下图形:
*
***
*****
***
*

代码示例:
public static void draw()//第19题,打出图形.菱形
{
int n=3; //自定义
//前三行的输出
for (int i = 1; i <= n; i++) { //控制行数
for (int j = 1; j <= n - i; j++) { //打印空格
System.out.print(" ");
}
for (int k = 0; k < i*2 -1; k++) { //打印*
System.out.print("*");
}
System.out.println();
}
//后两行的输出
for (int i = n-1; i >= 1;i--) {  //行数
for(int k = 1;k <= n-i;k++) {  //打印空格
System.out.print(" ");
}
for (int j = 1; j <= i*2 -1; j++) { //打印*
System.out.print("*");
}
System.out.println();
}
}