spring笔记-Formatter

1.内置Format

可以参考此篇文章
https://www.jianshu.com/p/c8f16cab35e1

2. Formatter

Parser负责输入，Printer负责输出

具体实现如下图:

可以跟以上一一对应

1. DateFormatter对应DateFormat
2. PercentStyleFormatter对应DecimalFormat，用于百分比格式化
3. NumberStyleFormatter对应数字格式化
4. CurrencyStyleFormatter对应货币类型数字格式化

2.1 demo示例

使用接口非常一致,都是parse方法和print方法

public class CurrencyStyleFormatterTests {

    private final CurrencyStyleFormatter formatter = new CurrencyStyleFormatter();
    @Test
    public void formatValue() {
        assertEquals("$23.00", formatter.print(new BigDecimal("23"), Locale.US));
    }

    @Test
    public void parseValue() throws ParseException {
        assertEquals(new BigDecimal("23.56"), formatter.parse("$23.56", Locale.US));
    }
}

public class NumberStyleFormatterTests {

    private final NumberStyleFormatter formatter = new NumberStyleFormatter();

    @Test
    public void formatValue() {
        assertEquals("23.56", formatter.print(new BigDecimal("23.56"), Locale.US));
    }

    @Test
    public void parseValue() throws ParseException {
        assertEquals(new BigDecimal("23.56"), formatter.parse("23.56", Locale.US));
    }
}

public class PercentStyleFormatterTests {

    private final PercentStyleFormatter formatter = new PercentStyleFormatter();

    @Test
    public void formatValue() {
        assertEquals("23%", formatter.print(new BigDecimal(".23"), Locale.US));
    }

    @Test
    public void parseValue() throws ParseException {
        assertEquals(new BigDecimal(".2356"), formatter.parse("23.56%", Locale.US));
    }
}

public class DateFormatterTests {

    private static final TimeZone UTC = TimeZone.getTimeZone("UTC");

    @Test
    public void shouldPrintAndParseDefault() throws Exception {
        DateFormatter formatter = new DateFormatter();
        formatter.setTimeZone(UTC);
        Date date = getDate(2009, Calendar.JUNE, 1);
        assertThat(formatter.print(date, Locale.US), is("Jun 1, 2009"));
        assertThat(formatter.parse("Jun 1, 2009", Locale.US), is(date));
    }
}

3.FormattingConversionService

FormattingConversionService继承自GenericConversionService,扩展自Conveter体系,t

3.1 FormatterRegistry

提供添加Foramtter接口, FormattingConversionService其内部实现还是转换为GenericConverter

3.2 示例

public class FormattingConversionServiceTests {

    private FormattingConversionService formattingService;

    @Before
    public void setUp() {
        formattingService = new FormattingConversionService();
        DefaultConversionService.addDefaultConverters(formattingService);
        LocaleContextHolder.setLocale(Locale.US);
    }

    @After
    public void tearDown() {
        LocaleContextHolder.setLocale(null);
    }

    @Test
    public void formatFieldForTypeWithFormatter() throws ParseException {
        formattingService.addFormatterForFieldType(Number.class, new NumberStyleFormatter());
        String formatted = formattingService.convert(3, String.class);
        assertEquals("3", formatted);
        Integer i = formattingService.convert("3", Integer.class);
        assertEquals(new Integer(3), i);
    }
}

4.FormattingConversionServiceFactoryBean

同样FormattingConversionService也有一个FactoryBean，也可以通过此方式来初始化FormattingConversionService并添加formatters

    @Test
    public void testCustomFormatter() throws Exception {
        FormattingConversionServiceFactoryBean factory = new FormattingConversionServiceFactoryBean();
        Set