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我們有一個需要轉換爲java bean的自定義數據結構。 該數據結構通常將所有內容都包含爲字符串，但該bean將具有輸入的屬性。使用Spring將自定義數據結構轉換爲bean
這些屬性在數據結構和bean中都被命名爲相同。
該bean的實際目標類型是在運行時確定的，爲了將它調好一點，我們還需要從自定義格式化的日期字符串轉換爲Joda DateTime對象。
因此，爲每種可能的類型編寫一個方法都很簡單，對此有什麼好的解決方案？
- ： -
因爲我的代碼是在Spring容器中運行，目前我正在去爲泉的BeanWrapper所以我沒有去關心標準轉換（字符串>的BigDecimal等），並配置它ConversionService +自定義轉換器
- 自定義屬性編輯
然而，BeanWrapperImpl中已經有一個紙條，上面寫着，它基本上是一個內部類，所以我有點困惑，應該如何使用，或者，如果有一個重新選擇。
下面是代碼：
import org.joda.time.DateTime;
import org.junit.Test;
import org.springframework.beans.BeanWrapper;
import org.springframework.beans.BeanWrapperImpl;
import org.springframework.core.convert.converter.Converter;
import org.springframework.core.convert.support.DefaultConversionService;
import java.beans.PropertyEditorSupport;
import java.math.BigDecimal;
import java.util.*;
import java.util.stream.Collectors;
public class BeanWrapperTest
{
private static InputDataStructure createInputDataStructure()
{
return new InputDataStructure(Arrays.asList(
map(mapEntry("name", "some name"),
mapEntry("bigDecimal", "12.34")),
map(mapEntry("dateTime", "2017-03-02T09:30:00.0Z"))
));
}
private Map<String, String> toMap(InputDataStructure inputDataStructure)
{
return inputDataStructure.data.stream()
.flatMap(innerMap -> innerMap.entrySet().stream())
.collect(Collectors.toMap(
Map.Entry::getKey,
Map.Entry::getValue
));
}
@Test
public void copy_alternative_using_conversion_service()
{
// set up a conversion service and add the special date converter
// and configure BeanWrapper with that conversion service
DefaultConversionService defaultConversionService = new DefaultConversionService();
defaultConversionService.addConverter(new CustomDateConverter());
BeanWrapper beanWrapper = new BeanWrapperImpl(DestinationClass.class);
beanWrapper.setConversionService(defaultConversionService);
// copy all values into a Map
// and loop over that map and use BeanWrapper to copy the properties
Map<String, String> values = toMap(createInputDataStructure());
values.forEach(beanWrapper::setPropertyValue);
// bam!
System.out.println(beanWrapper.getWrappedInstance());
}
@Test
public void copy_alternative_using_formatters()
{
// configure BeanWrapper with a custom property editor
BeanWrapper beanWrapper = new BeanWrapperImpl(DestinationClass.class);
beanWrapper.registerCustomEditor(DateTime.class, new CustomDateEditor());
// copy all values into a Map
// and loop over that map and use BeanWrapper to copy the properties
Map<String, String> values = toMap(createInputDataStructure());
values.forEach(beanWrapper::setPropertyValue);
// bam!
System.out.println(beanWrapper.getWrappedInstance());
}
@SafeVarargs
private static <K, V> Map<K, V> map(Map.Entry<K, V>... entries)
{
Map<K, V> map = new HashMap<>();
for (Map.Entry<K, V> e : entries) {
map.put(e.getKey(), e.getValue());
}
return map;
}
private static <K, V> Map.Entry<K, V> mapEntry(K key, V value)
{
return new AbstractMap.SimpleImmutableEntry<>(key, value);
}
private static class InputDataStructure
{
private final List<Map<String, String>> data;
InputDataStructure(List<Map<String, String>> data)
{
this.data = data;
}
}
private static class DestinationClass
{
private String name;
private BigDecimal bigDecimal;
private DateTime dateTime;
public String getName()
{
return name;
}
public DestinationClass setName(String name)
{
this.name = name;
return this;
}
public BigDecimal getBigDecimal()
{
return bigDecimal;
}
public DestinationClass setBigDecimal(BigDecimal bigDecimal)
{
this.bigDecimal = bigDecimal;
return this;
}
public DateTime getDateTime()
{
return dateTime;
}
public DestinationClass setDateTime(DateTime dateTime)
{
this.dateTime = dateTime;
return this;
}
@Override public String toString()
{
return "DestinationClass{" + "name='" + name + '\'' +
", bigDecimal=" + bigDecimal +
", dateTime=" + dateTime +
'}';
}
}
private static class CustomDateConverter implements Converter<String, DateTime>
{
@Override public DateTime convert(String source)
{
// try whatever date format would be expected
return DateTime.parse(source);
}
}
private class CustomDateEditor extends PropertyEditorSupport
{
@Override
public void setAsText(String text)
{
// try whatever date format would be expected
setValue(DateTime.parse(text));
}
}
}