28-springMvc注解开发-类型转换器-白红宇

28-springMvc注解开发-类型转换器

阅读量：243 次

发布时间：2019-03-01

本文共 2213 字，大约阅读时间需要 7 分钟。


   
   
   
   
   
    
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实现数据类型转换
   
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.springboot.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) {        if (StringUtils.isEmpty(source)) {            throw new NullPointerException("Source can not be null!");        }        try {            DateFormat format = new SimpleDateFormat("yyyy-MM-dd");            return format.parse(source);        } catch (Exception e) {            e.printStackTrace();        }        return null;    }}
    
   
注册
   
package study.wyy.springboot.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) {        ConversionService conversionService = dataBinder.getConversionService();        if (conversionService instanceof GenericConversionService) {            GenericConversionService genericConversionService = (GenericConversionService) conversionService;            genericConversionService.addConverter(stringToDateConverter);        }    }}