package baseDemo1;

/**
 * printf的一些常用的打印格式总结
 * @author chen 2014年11月27日16:26:07
 * */
public class PrintfDemo {
	public static void main(String[] args) {
		String str = "I like data mining";
		int i = 1234;
		double d = 3.14159265358979;
		float f1 = -0.123456f;
		float f2 = 0.123456f;
		
		System.out.printf("1，str = %20s\n", str); //String类型
		
		System.out.printf("2，i = %d\n", i); //int类型
		
		System.out.printf("3，d = %f\n", d); //double类型，默认小数是6位
		
		/*10表示输出的长度，从右至左所有数字和字符的长度，
		如果字符没有10个，则左边补上空格；若大于10个，字符全部打印出来*/
		System.out.printf("4，d = %10f\n", d); 
		System.out.printf("5，d = %.2f\n", d); //.2表示小数点的位数
		System.out.printf("6，f1 = %f\n", f1); //flaot类型
		System.out.printf("7，f2 = %f\n", f2); //float类型，正数的时候，无符号
		System.out.printf("8，f2 = %+f\n", f2); //float类型，正数的时候，显示数字的符号
		
		System.out.printf("9，%%"); //打印“%”，只写一个%会报错
		
		System.out.println();
		System.out.println("");
		PrintfDemo.nineNine();
	}
	
	/**
	 * Description:打印九九乘法表
	 * */
	static void nineNine(){
		
		for (int i = 1; i < 10; i++){
			for (int j = 1; j <= i; j++){
				System.out.printf("%d*%d =%2d ", i, j, i*j); 
			}
			
			System.out.println();
		}
	}
}

打印结果：

1，str =   I like data mining
2，i = 1234
3，d = 3.141593
4，d =   3.141593
5，d = 3.14
6，f1 = -0.123456
7，f2 = 0.123456
8，f2 = +0.123456
9，%
1*1 = 1 
2*1 = 2 2*2 = 4 
3*1 = 3 3*2 = 6 3*3 = 9 
4*1 = 4 4*2 = 8 4*3 =12 4*4 =16 
5*1 = 5 5*2 =10 5*3 =15 5*4 =20 5*5 =25 
6*1 = 6 6*2 =12 6*3 =18 6*4 =24 6*5 =30 6*6 =36 
7*1 = 7 7*2 =14 7*3 =21 7*4 =28 7*5 =35 7*6 =42 7*7 =49 
8*1 = 8 8*2 =16 8*3 =24 8*4 =32 8*5 =40 8*6 =48 8*7 =56 8*8 =64 
9*1 = 9 9*2 =18 9*3 =27 9*4 =36 9*5 =45 9*6 =54 9*7 =63 9*8 =72 9*9 =81 

java printf的一些常用的打印格式总结