【ThinkingInJava】26、java字符串格式化说明符

/**
* 书本:《Thinking In Java》
* 功能:对于java字符串格式化说明符
* 		format字符串的格式化参数语法如下：
* 		%[argument_index$][flags][width][.precision]conversion
* 文件:Receipt.java
* 时间:2015年4月11日19:40:53
* 作者:cutter_point
*/
package Lesson13_strings;

import java.util.Formatter;

public class Receipt 
{
	private double total = 0;
	private Formatter f = new Formatter(System.out);	//指定输出的目的地
	
	public void printTitle()		//输出标题
	{
		//这个格式第一个%-15s 是说宽度为15的字符串，后面类同，只是-还是不太清楚是个什么
		f.format("%-15s %5s %10s\n", "Item", "Qty", "Price");
		f.format("%-15s %5s %10s\n", "----", "---", "-----");
	}
	
	public void print(String name, int qty, double price)
	{
		f.format("%-15.15s %5d %10.2f\n", name, qty, price);
		total += price;
	}
	
	public void printTotal()
	{
		f.format("%-15.15s %5s %10.2f\n", "Tax", "", total*0.06);
		f.format("%-15s %5s %10s\n", "", "", "------");
		f.format("%-15.15s %5s %10.2f\n", "Total", "", total*1.06);
	}
	
	public static void main(String [] args)
	{
		Receipt receipt = new Receipt();
		receipt.printTitle();
		receipt.print("Jack's Magic Beans", 4, 4.25);
	    receipt.print("Princess Peas", 3, 5.1);
	    receipt.print("Three Bears Porridge", 1, 14.29);
	    receipt.printTotal();
	    Formatter ff = new Formatter(System.out);
	    ff.format("%5d", 998);
	}

}

输出：

Item              Qty      Price
----              ---      -----
Jack's Magic Be     4       4.25
Princess Peas       3       5.10
Three Bears Por     1      14.29
Tax                         1.42
                          ------
Total                      25.06
  998