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2 .排版格式的控制能力
package string;
import java.util.Formatter;
public class Receipt {
private double total = 0;
private Formatter f = new Formatter(System.out);
public void printTitle() {
//-表示左对齐
f.format(“%-15s %5s %10s\n”, “Item”, “Qty”, “Price”);
f.format(“%-15s %5s %10s\n”, “—“, “—“, “—“);
}
public void print(String item, int qty, double price) {
f.format(“%-15.15s %5d %10.2f\n”, item, qty, price);
total += price;
}
public void printTotal() {
f.format(“%-15s %5s %10.2f\n”, “Tax”, “”, total*0.06);
f.format(“%-15s %5s %10s\n”, “”, “”, “—“);
f.format(“%-15s %5s %10.2f\n”, “Total”, “”, total*1.06);
}
public static void main(String[] args) {
Receipt r = new Receipt();
r.printTitle();
r.print(“big ice”, 2, 9);
r.print(“little ice”, 1, 1.25);
r.print(“old ice”, 5, 5.5);
r.printTotal();
}
}
//output
Item Qty Price
— — —
big ice 2 9.00
little ice 1 1.25
old ice 5 5.50
Tax 0.95
—
Total 16.70
3.类型转换
package string;
import java.math.BigInteger;
import java.util.Formatter;
public class Conversion {
public static void main(String[] args) {
Formatter f = new Formatter(System.out);
char u = ‘a’;
System.out.println(“——–u = ‘a'”);
f.format(“s: %s\n”, u); //字符串
f.format(“c: %c\n”, u); //Unicode 字符
f.format(“b: %b\n”, u); //boolean值
f.format(“h: %h\n”, u); //16进制哈希值
int v = 21;
System.out.println(“\n———-v = 21”);
f.format(“d: %d\n”, v); //十进制整数
f.format(“c: %c\n”, v); //Unicode 字符
f.format(“b: %b\n”, v); //boolean值
f.format(“s: %s\n”, v); //字符串
f.format(“x: %x\n”, v); //16进制整数
f.format(“h: %h\n”, v); //16进制哈希值 hasCode–>toHex
BigInteger w = new BigInteger(“5000000000000”);
System.out.println(“\n——-w = new BigInteger(\”5000000000000\”)”);
f.format(“d: %d\n”, w); //十进制整数
f.format(“b: %b\n”, w); //boolean值
f.format(“s: %s\n”, w); //字符串
f.format(“x: %x\n”, w); //16进制整数
f.format(“h: %h\n”, w); //16进制哈希值 hasCode–>toHex
double x = 1234.567;
System.out.println(“\n——-x = 1234.567”);
f.format(“b: %b\n”, x); //boolean
f.format(“s: %s\n”, x); //字符串
f.format(“f: %f\n”, x); //float
f.format(“e: %e\n”, x); //计算机科学记数法表示的十进制数
f.format(“h: %h\n”, x); //16进制哈希值 hasCode–>toHex
Conversion c = new Conversion();
System.out.println(“\n——-c = new Conversion()”);
f.format(“b: %b\n”, c); //boolean
f.format(“s: %s\n”, c); //字符串
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而在于当时的那份心情。可是旅行的彼时那刻我的心情一直是好的吗？
