引言
当我们通过@configurationproperties注解实现配置 bean的时候,如果默认的配置属性转换无法满足我们的需求的时候,我们可以根据自己的需求通过以下扩展方式对配置属性进行转换
propertyeditorsupport实现
下面的例子是把属性中定义的字符串转换成movie,并且把name的值大写
继承propertyeditorsupport并且实现propertyeditorregistrar接口
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package com.paderlol.spring.practice.properties.editor;import com.paderlol.spring.practice.properties.pojo.movie;import java.beans.propertyeditorsupport;import lombok.extern.slf4j.slf4j;import org.springframework.beans.propertyeditorregistrar;import org.springframework.beans.propertyeditorregistry;/** * @author pader propertyeditor 在不同的包下面 */@slf4jpublic class custommovieeditor extends propertyeditorsupportimplements propertyeditorregistrar { @override public string getastext() { movie movie = (movie) getvalue(); return movie == null ? "" : movie.getname(); } @override public void setastext(string text) throws illegalargumentexception { log.info("继承[propertyeditorsupport]类,转换数据={}", text); string[] data = text.split("-"); movie movie = movie.builder().name(data[0] .touppercase()).seat(integer.parseint(data[1])) .build(); setvalue(movie); } @override public void registercustomeditors(propertyeditorregistry registry) { registry.registercustomeditor(movie.class,this); }} |
注册自定义的propertyeditor
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@beanpublic customeditorconfigurer customeditorconfigurer() { customeditorconfigurer customeditorconfigurer = new customeditorconfigurer(); // 有两种注册方式 这是第一种 customeditorconfigurer.setpropertyeditorregistrars( new propertyeditorregistrar[]{ new custommovieeditor() }); // 第二 种 map<class<?>,class<? extends propertyeditor>> maps = new hashmap<>(); maps.put(movie.class,custommovieeditor.class); return customeditorconfigurer;} |
converter接口+@configurationpropertiesbinding注解
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//注意@component@configurationpropertiesbindingpublic class stringtopersonconverter implements converter<string, person> { @override public person convert(string from) { log.info("使用[converter]接口,转换数据={}", from); string[] data = from.split(","); return person.builder().name(data[0]).age(integer.parseint(data[1])).build(); }} |
总结
- 以上两种实现方式结果,但是converter接口相比propertyeditor接口更加灵活一些,propertyeditor接口仅限于string转换,converter可以自定义别的,并且propertyeditor接口通常用于controller中的接收参数的转换。
- @configurationpropertiesbinding是限定符注解@qualifier的派生类而已,参考org.springframework.boot.context.properties.conversionservicededucer，以下是源代码片段
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@autowired(required = false)@configurationpropertiesbindingpublic void setconverters(list<converter<?, ?>> converters) { this.converters = converters;}/*** a list of custom converters (in addition to the defaults) to use when* converting properties for binding.* @param converters the converters to set*/@autowired(required = false)@configurationpropertiesbindingpublic void setgenericconverters(list<genericconverter> converters) {this.genericconverters = converters; } |
- formatter接口是不能对属性完成转换的,因为conversionservicededucer初始化的时候只获取genericconverter和converter接口
- 官方文档上还介绍了可以使用实现org.springframework.core.convert.conversionservice并且bean名称也必须叫conversionservice，不过大部分情况不推荐自己通过这种方式去实现这个接口,因为自己实现的conversionservice会替代默认的。具体参考conversionservicededucer源码：
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public conversionservice getconversionservice() { try { //默认首先寻找bean名称叫conversionservice的conversionservice的bean类 return this.applicationcontext.getbean( configurableapplicationcontext.conversion_service_bean_name, conversionservice.class); } catch (nosuchbeandefinitionexception ex) { //找不到就默认生成applicationconversionservice类 return this.applicationcontext.getautowirecapablebeanfactory() .createbean(factory.class).create(); }} |
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持服务器之家。
原文链接：https://segmentfault.com/a/1190000016941868
