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1 Converter接口

@FunctionalInterfacepublic interface Converter
   
     {
   	/**	提供类型转换的逻辑	 */	@Nullable	T convert(S source);}
   

2 案例

之前通过InitBinder和DateTimeFormat注解实现过字符串转date，现在也可以通过Converter实现该功能

package study.wyy.spring.anno.web.convert;import org.springframework.core.convert.converter.Converter;import org.springframework.stereotype.Component;import org.springframework.util.StringUtils;import java.text.DateFormat;import java.text.SimpleDateFormat;import java.util.Date;/** * @author by wyaoyao * @Description * @Date 2021/2/15 7:49 下午 */@Componentpublic class String2DateConverter implements Converter
   
     {
          @Override    public Date convert(String source) {
           //1.判断来源是否有值        if (StringUtils.isEmpty(source)) {
               throw new NullPointerException("Source can not be null!");        }        try{
               //2.定义转换器            DateFormat format = new SimpleDateFormat("yyyy-MM-dd");            //3.转换并返回            return format.parse(source);        }catch (Exception e){
               e.printStackTrace();        }        return null;    }}
   

注册

package study.wyy.spring.anno.web.advice;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.core.convert.ConversionService;import org.springframework.core.convert.converter.Converter;import org.springframework.core.convert.support.GenericConversionService;import org.springframework.format.datetime.DateFormatter;import org.springframework.web.bind.WebDataBinder;import org.springframework.web.bind.annotation.ControllerAdvice;import org.springframework.web.bind.annotation.InitBinder;@ControllerAdvicepublic class DataFormatAdvice {
       @Autowired    private Converter stringToDateConverter;    @InitBinder    public void dateBinder(WebDataBinder dataBinder){
           //1.获取转换服务对象        ConversionService conversionService = dataBinder.getConversionService();        //2.判断conversionService是否为GenericConversionService类型        if(conversionService instanceof GenericConversionService){
               //3.强转            GenericConversionService genericConversionService = (GenericConversionService)conversionService;            //4.添加类型转换器            genericConversionService.addConverter(stringToDateConverter);        }    }}

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