格式化和解析

1 数字格式

NumberFormat 类接受 Locale 参数，静态工厂方法 getNumberInstance、getCurrencyInstance、getPercentInstance 分别返回对数字、货币量、百分比的格式化和解析。

NumberFormat currFmt = NumberFormat.getCurrencyInstance(Locale.CHINA);
double amt = 123456.78;
String result = currFmt.format(amt);//￥123,456.78

2 货币

Currency 类控制被格式器所处理的货币

NumberFormat cnyFmt = NumberFormat.getCurrencyInstance(Locale.US);
cnyFmt.setCurrency(Currency.getInstance("CNY"));
double amt = 123456.78;
String result = currFmt.format(amt);//CNY123,456.78

3 日期和时间

java.time 包 DateTimeFormatter 类

3.1 格式化

format() 方法：Date -> String

FormatStyle style = FormatStyle.SHORT;
//当前Locale
DateTimeFormatter dateFormatter = DateTimeFormatter.ofLocalizedDate(style);
//切换Locale
DateTimeFormatter timeFormatter = DateTimeFormatter.ofLocalizedTime(style).withLocale(locale);
DateTimeFormatter dateTimeFormatter = DateTimeFormatter.ofLocalizedDateTime(style);

ZonedDateTime appointment = ...;
String formatted = formatter.format(appointment);

3.2 解析

parse() 方法：String -> Date

LocalTime time = LocalTime.parse("9:32 AM",formatter);