Java中不同转换符实现不同数据类型到字符串的转换

忘是亡心i 2022-06-16 06:45 188阅读 0赞

String类的format()方法用于创建格式化的字符串以及连接多个字符串对象。熟悉C语言的同学应该记得C语言的sprintf()方法，两者有类似之处。format()方法有两种重载形式。

format(String format, Object... args) 新字符串使用本地语言环境，制定字符串格式和参数生成格式化的新字符串。

format(Locale locale, String format, Object... args) 使用指定的语言环境，制定字符串格式和参数生成格式化的字符串。

显示不同转换符实现不同数据类型到字符串的转换，如图所示。

<table style="margin:0px; padding:0px; border-collapse:collapse; border-spacing:0px; border:1px solid silver; word-break:break-word; color:rgb(85,85,85); font-family:verdana,'ms song',宋体,Arial,微软雅黑,Helvetica,sans-serif; font-size:12px; line-height:24px; background-color:rgb(245,248,250)"> 
 <tbody style="margin:0px; padding:0px"> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> 转&nbsp; 换&nbsp; 符 </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> 说&nbsp;&nbsp;&nbsp; 明&nbsp; </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> 示&nbsp;&nbsp;&nbsp; 例 </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> %s </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> 字符串类型 </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> "mingrisoft" </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> %c </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> 字符类型 </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> 'm' </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> %b </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> 布尔类型 </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> true </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> %d </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> 整数类型（十进制） </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> 99 </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> %x </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> 整数类型（十六进制） </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> FF </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> %o </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> 整数类型（八进制） </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> 77 </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> %f </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> 浮点类型 </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> 99.99 </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> %a </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> 十六进制浮点类型 </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> FF.35AE </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> %e </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> 指数类型 </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> 9.38e+5 </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> %g </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> 通用浮点类型（f和e类型中较短的） </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> &nbsp;</td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> %h </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> 散列码 </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> &nbsp;</td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> %% </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> 百分比类型 </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> ％ </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> %n </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> 换行符 </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> &nbsp;</td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> %tx </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> 日期与时间类型（x代表不同的日期与时间转换符 </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> &nbsp;　　　　</td> 
 </tr> 
 </tbody> 
</table>

测试用例

![复制代码][copycode.gif]

public static void main(String[] args) { String str=null; str=String.format("Hi,%s", "王力"); System.out.println(str); str=String.format("Hi,%s:%s.%s", "王南","王力","王张"); System.out.println(str); System.out.printf("字母a的大写是：%c %n", 'A'); System.out.printf("3>7的结果是：%b %n", 3>7); System.out.printf("100的一半是：%d %n", 100/2); System.out.printf("100的16进制数是：%x %n", 100); System.out.printf("100的8进制数是：%o %n", 100); System.out.printf("50元的书打8.5折扣是：%f 元%n", 50*0.85); System.out.printf("上面价格的16进制数是：%a %n", 50*0.85); System.out.printf("上面价格的指数表示：%e %n", 50*0.85); System.out.printf("上面价格的指数和浮点数结果的长度较短的是：%g %n", 50*0.85); System.out.printf("上面的折扣是%d%% %n", 85); System.out.printf("字母A的散列码是：%h %n", 'A'); }

![复制代码][copycode.gif]

[copycode.gif]: /images/20220616/6fcd033c404f40509f3627c7b197c0fc.png